Journal articles: 'Cu based ZrO2'

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Volochko, A. T., V. A. Zelenin, E. O. Narushko, A. V. Skilandz, and G. V. Markov. "MODEL OF TRANSMISSION OF MULTILAYER COATINGS BASED ON THE Cu-ZrO2 SYSTEM IN THE OPTICAL WAVELENGTH RANGE." Doklady BGUIR, no. 6 (October 3, 2019): 87–94. http://dx.doi.org/10.35596/1729-7648-2019-124-6-87-94.

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The transmission model for optical diapason was developed for multilayer coatings consisting of alternating layers of copper and zirconium dioxide deposited on K8 glass substrates. The model is based on the laws of light interference. It was shown that the transmission in the optical range of a 60 nm thick Cu layer with a surface resistance ρ = 1 Ohm/sq is 4–5 %, and the transmission of the ZrO2/Cu/ZrO2/Cu/К8 coating obtained by dividing a 60 nm thick copper layer into two sublayers at 30 nm with the application of antireflection layers of ZrO2 on them, at ρ = 1.2 Ohm/sq it reaches 25 %. The thicknesses and the number of layers of the Cu-ZrO2 system were calculated, which ensure a transmission in the wavelength range of 400–700 nm of at least 45 %. The permissible thickness of Cu layers (≥ 20 nm) was determined, below which, due to their insular structure and partial oxidation with the formation of Cu2O, the electrical conductivity of the multilayer coating sharply decreases (ρ ≥ 100 Ohm/sq).

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Yotkeaw, Thanyaporn, Nattaya Tosangthum, Rungtip Krataitong, Monnapas Morakotjinda, Jirapat Prapai, and Ruangdaj Tongsri. "Sintered Frictional Materials Based on Cu Powders." Advanced Materials Research 747 (August 2013): 55–58. http://dx.doi.org/10.4028/www.scientific.net/amr.747.55.

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Sintered frictional materials (SFMs) were fabricated by using powder metallurgical process. Powder formulations were experimented to investigate effects of Sn, C and ZrO2 additions on mechanical and tribological properties of the sintered composites made for dry frictional materials applications. The developed SFMs consisted of non-lead friction material. Natural sand (SiO2) and ZrO2 were employed instead of lead oxide to provide frictional components. Interrelationships between chemical composition, sintering temperature, friction coefficient, wear behavior and mechanical property of the SFMs have been studied. It was found that sintering temperature affected hardness property of the SFMs. The hardness was also affected by SFM compositions. Friction coefficient increased with increasing ZrO2 content. Addition of natural sand resulted in decrease of the hardness of the SFMs. Graphite also affected hardness and friction coefficient of SFMs containing no sand. Employing prealloyed Cu-Sn powders provided SFMs with better mechanical properties compared to the SFMs made of admixed Cu and Sn powders.

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Szummer, A., M. Janik-Czachor, P. Mack, and M. Pisarek. "Electron Probe and Auger Electron Microprobe Characterization of Modified Cu-Based Amorphous Alloys." Microscopy and Microanalysis 9, no. 4 (2003): 359–67. http://dx.doi.org/10.1017/s1431927603030290.

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Changes in morphology and local chemical composition due to various methods of modification of surfaces of Cu-Zr, Cu-Hf, and Cu-Ti amorphous alloys (caused by aging in air/dry corrosion or hydrogen charging) were investigated. These modification/activation procedures transform the original amorphous ribbons of low surface area into efficient and stable catalysts, due to the segregation of a distinct amount of Cu and the development of a large specific surface area of Cu on a ZrOx or HfOx support. It was found that aging in air resulted in the formation of a bilayer of rough copper (containing small Cu particles indispensable for catalysis) on top of a rather smooth oxide underlayer (ZrOx, HfOx). Careful examination of the cross sections of the modified Cu-based ribbons revealed that, even after prolonged aging in air, only the first few microns of the surface layer was modified. Cu-Ti alloy was stable in air and did not undergo the expected modification. Hydrogenation followed by air exposure resulted in a disintegration of the ribbons into small pieces. Each piece was covered with many small Cu clusters 0.1–0.5 μm in diameter formed on an oxide underlayer. High-energy resolution Auger spectroscopy allowed identification of the underlayers (ZrO2, HfO2, or TiOx), identification of small Cu clusters, determination of the degree of surface oxidation of them, and mapping of the surface to identify the Cu-covered and “naked” heavy metal.

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Mithun, Kumar Ghosh, Kumar Sahu Sanjay, Sahoo Debasis, and Kumar Ghorai Tanmay. "Green synthesis, characterization and photocatalytic study of Cu based ZrO2 nanoparticles." Journal of Indian Chemical Society Vol. 97, No. 9b, Sept 2020 (2020): 1507–13. https://doi.org/10.5281/zenodo.5657009.

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Nanomaterials and Crystal Design Laboratory, Department of Chemistry, Indira Gandhi National Tribal University, Amarkantak-484 887, Madhya Pradesh, India E-mail: tanmay.ghorai@igntu.ac.in/tanmayghorai66@gmail.com Manuscript received online 02 July 2020, accepted 29 August 2020 Green synthesis has been adopted for the synthesis of Cu based ZrO2 nanoparticles via the co-precipitation method. Different mole percentage of copper was incorporated in zirconia and prepare various Cu2xZr1-xO2 (x = 0.05, 0.1, 0.2, 0.3, 0.4) nanoparticles. Among all the compositions Cu2xZr1-xO2 (x = 0.05) (CZ) exhibits higher photocatalytic activity compare to pure ZrO2 and other compositions for degradation of naphthyl orange (NO) under visible light in the aqueous medium. Most interesting that the mol% of Cu2+ ion in the mother composition is increased, the degradation rate of NO is decreased but CZ takes only 45 min to decolourize NO completely. The comparative study was also investigated in various model dyes like methyl orange (MO), methyl red (MR), rhodamine B (RhB) including NO in presence of catalysts and oxidation of NO spectra was recorded at constant time interval. CZ nanoparticles were characterized by a host of different techniques such as X-ray diffraction, FTIR, SEM and UV-Visible spectroscopy. The phase structure of Cu2xZr1-xO2 was cubic and crystallite sizes was found to be 17±1 nm, which was also compatibility from grain sizes of nanoparticles 20±1 nm (SEM analysis). The band gap of Cu2xZr1-xO2 is 5.03 eV calculated from the optical measurement.

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Liu, Y., J. Hu, Y. Zhang, and Z. Guo. "Interface microstructure of the brazed zirconia and Ti-6Al-4V using Ti-based amorphous filler." Science of Sintering 45, no. 3 (2013): 313–21. http://dx.doi.org/10.2298/sos1303313l.

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The polycrystalline ZrO2?3mol.%Y2O3 was brazed to Ti-6Al-4V using a Ti47Zr28Cu14Ni11 (at.%) amorphous ribbon at 1123 K in a high vacuum. The microstructure of the interface and evolution mechanism of the joint was investigated. The experimental result showed that the typical interfacial microstructures of the joints consisted of ZrO2/TiO+TiO2+Cu2Ti4O+Ni2Ti4O/?-Ti+(Ti,Zr)2(Cu,Ni) eutectic/(Ti,Zr)2(Cu,Ni)/acicular Widmanst?ten structure/Ti-6Al-4V alloy. The microstructure of the brazed joint was related to the solution and chemical reaction among atoms during brazing. According to the mechanical property tests the joint brazed at 1123 K for 30 min obtained the maximum shear strength 63 MPa. Both the white block intermetallic compound (Ti,Zr)2(Cu,Ni) and the coarse ?-Ti+(Ti,Zr)2(Cu,Ni) eutectic structure should be avoided forming in the brazed joint.

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Din, Israf Ud, Maizatul Shima Shaharun, Duvvuri Subbarao, and A. Naeem. "Synthesis, Characterization and Activity Pattern of Carbon Nanofibres Based Cu-ZrO₂ Catalyst in the Hydrogenation of Carbon Dioxide to Methanol." Advanced Materials Research 925 (April 2014): 349–53. http://dx.doi.org/10.4028/www.scientific.net/amr.925.349.

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Carbon nanofibers based Cu-ZrO2 catalysts (Cu-ZrO2/CNF) were synthesized by deposition precipitation method. Carbon nanofibers of herringbone type were used as a catalyst support. Before using as catalyst support, carbon nanofibers were oxidized to (CNF-O) with 10 % (v/v) nitric acid solution. A series of catalyst with various copper loadings of 10, 15 and 20 wt% were synthesized. X-ray diffraction (XRD) study revealed that degree of crystallization of catalyst increase with increasing the concentration of copper content in the catalyst. BET studies showed higher surface area for low loading of copper. Temperature-Programmed Reduction (TPR) analyses concluded good interaction of catalyst particles with higher loading of copper. The performance of Cu-ZrO2/CNF catalysts in hydrogenation of CO2 reaction was studied in slurry-typed reactor at 443 K, 30 bar and H2: CO2 ratio of 3:1. The highest yield of methanol was achieved using the 20 wt% copper loading.

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Hussain, Sajid, Eleonora Aneggi, Daniele Goi, and Alessandro Trovarelli. "Bimetallic Cu/Fe Catalysts for Ibuprofen Mineralization." Catalysts 11, no. 11 (2021): 1383. http://dx.doi.org/10.3390/catal11111383.

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At present, the use of conventional wastewater processes is becoming increasingly challenging, mainly due to the presence of biorecalcitrant organic matter. Advanced oxidation processes such as Fenton, Fenton-like and hybrid processes have been successfully employed for the treatment of highly concentrated and toxic non-biodegradable pollutants. Here, a series of bimetallic catalysts, based on Cu/Fe supported over ZrO2, were investigated for the mineralization of ibuprofen with a heterogeneous Fenton-like reaction. The materials were prepared by incipient wetness impregnation and characterized by standard techniques. Temperature-programmed experiments highlighted the promotion of the reduction in CuO due to the synergistic effects of the coupled redox cycles of copper (Cu2+/Cu+) and iron (Fe+3/Fe+2). 5%Cu-5%Fe/ZrO2 not only displays the highest ibuprofen mineralization (83%) under optimum conditions but also exploits its activity in a wider range of pH (3–5) with extremely low metal leaching. The recycling of bimetallic catalysts reveals that only the 5%Cu-5%Fe/ZrO2 system is able to provide sustainable activity in heterogeneous Fenton process.

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Wu, Yingquan, Li Tan, Tao Zhang, et al. "Effect of Preparation Method on ZrO2-Based Catalysts Performance for Isobutanol Synthesis from Syngas." Catalysts 9, no. 9 (2019): 752. http://dx.doi.org/10.3390/catal9090752.

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Two types of amorphous ZrO2 (am-ZrO2) catalysts were prepared by different co-precipitation/reflux digestion methods (with ethylenediamine and ammonia as the precipitant respectively). Then, copper and potassium were introduced for modifying ZrO2 via an impregnation method to enhance the catalytic performance. The obtained catalysts were further characterized by means of Brunauer-Emmett-Teller surface areas (BET), X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), and In situ diffuse reflectance infrared spectroscopy (in situ DRIFTS). CO hydrogenation experiments were performed in a fixed-bed reactor for isobutanol synthesis. Great differences were observed on the distribution of alcohols over the two types of ZrO2 catalysts, which were promoted with the same content of Cu and K. The selectivity of isobutanol on K-CuZrO2 (ammonia as precipitant, A-KCZ) was three times higher than that on K-CuZrO2 (ethylenediamine as precipitant, E-KCZ). The characterization results indicated that the A-KCZ catalyst supplied more active hydroxyls (isolated hydroxyls) for anchoring and dispersing Cu. More importantly, it was found that bicarbonate species were formed, which were ascribed as important C1 species for isobutanol formation on the A-KCZ catalyst surface. These C1 intermediates had relatively stronger adsorption strength than those adsorbed on the E-KCZ catalyst, indicating that the bicarbonate species on the A-KCZ catalyst had a longer residence time for further carbon chain growth. Therefore, the selectivity of isobutanol was greatly enhanced. These findings would extend the horizontal of direct alcohols synthesis from syngas.

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Németh, Dóra, and Margit Eniszné Bódogh. "Thermal interactions between the Y-Ba-Cu-O based superconductors and ZrO2 substrates." Epitoanyag - Journal of Silicate Based and Composite Materials 63, no. 3-4. (2011): 48–51. http://dx.doi.org/10.14382/epitoanyag-jsbcm.2011.8.

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Song, Mouxiao, Li Li, Xueshuang Wu, Haiqing Cai, Guiying Li, and Changwei Hu. "The Influence of the ZrO2 Crystal Phase on Cu/ZrO2-Al2O3 Catalysts in Methanol Steam Reforming." Catalysts 14, no. 8 (2024): 480. http://dx.doi.org/10.3390/catal14080480.

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Copper-based catalysts are widely used in methanol steam reforming to produce hydrogen. In this paper, the supportive effect of the crystal phase of ZrO2 on Cu-based catalysts in methanol steam reforming is discussed. Monoclinic(m-), Tetragonal(t-) and mixed ZrO2 phases were prepared, and structure–activity relationships were investigated with XRD, H2-TPR, BET, HR-TEM and XPS. It was found that the catalyst with a 81.4% monoclinic ZrO2 crystal phase exhibited the highest methanol conversion (88.5%) and the highest hydrogen production rate (104.6 μmol/gcat·s) at 275 °C as it displayed the best reducing properties and more oxygen vacancies on the catalyst surface. Oxygen vacancies can produce more Cu1+ + Cu0, which is the active species for methanol steam reforming on the catalyst surface, and therefore affect catalytic activity.

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Jeong, Dae-Woon, Hyun-Suk Na, Jae-Oh Shim, Won-Jun Jang, and Hyun-Seog Roh. "A crucial role for the CeO2–ZrO2 support for the low temperature water gas shift reaction over Cu–CeO2–ZrO2 catalysts." Catalysis Science & Technology 5, no. 7 (2015): 3706–13. http://dx.doi.org/10.1039/c5cy00499c.

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Bergamaschi, V. S., F. M. S. Carvalho, W. R. Santos, and C. Rodrigues. "Synthesis and Characterization of Ni-Cu/ZrO₂ and Co-Cu/ ZrO₂ Catalysts Used for Ethanol Steam Reforming." Materials Science Forum 530-531 (November 2006): 619–24. http://dx.doi.org/10.4028/www.scientific.net/msf.530-531.619.

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Zirconia has received much attention as catalysts for its high surface area and acid-base property. The textural and acid-base properties of ZrO2 depend on both, the synthesis procedure and the calcinations temperature. The aim of the present study is the preparation and characterization of nickel/cupper/zirconia and cobalt/cupper/zirconia microspheres using hydrolysis process. This process is based on homogeneous hydrolysis of droplets of a concentrated ZrO2(NO3)2-urea solution after adding hexamethyletetramine. Gelation was conduced successfully and the gel spheres were dried at 80 °C. The dried gel spheres were thermally treated at 550 °C. Characterization of the samples was performed using X-ray diffraction (XRD), BET nitrogen adsorption, scanning electron microscopy (SEM), thermogravimetric (TGA) and UV-Vis spectroscopy. The performance of the microspheres was investigated as catalysts in steam reforming of ethanol. Theses catalysts exhibit a good selectivity for hydrogen.

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Ud Din, Israf, Maizatul S. Shaharun, Duvvuri Subbarao, and A. Naeem. "Homogeneous Deposition Precipitation Method for Synthesis of Carbon Nanofibre Based Cu-ZrO₂ Catalyst for Hydrogenation of CO₂ to Methanol." Applied Mechanics and Materials 446-447 (November 2013): 83–87. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.83.

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Deposition precipitation method was employed to synthesize carbon nanofiber based Cu-ZrO2catalyst (Cu-ZrO2/CNF). Carbon nanofibre of herringbone type was used as a catalyst support. Prior deposition of catalyst particles, carbon nanofibre was oxidized to (CNF-O) with nitric acid solution. Catalyst was characterized by X-ray diffraction (XRD), Fourier Transmission Infrared (FTIR), Transmission Electron Microscopy (TEM) and Temperature-Programmed Reduction (TPR). Highly loaded, well-dispersed and thermally stable catalyst particles with average size of 4 nm were obtained by deposition precipitation method. Reaction studies confirmed the activity of the catalyst towards methanol formation.

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Wang, Yongsheng, Zhenzhen Zhao, Yunlu Zhao, et al. "A ZrO2-RGO composite as a support enhanced the performance of a Cu-based catalyst in dehydrogenation of diethanolamine." RSC Advances 9, no. 52 (2019): 30439–47. http://dx.doi.org/10.1039/c9ra05458h.

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Karbowski, Andrzej, Janusz D. Fidelus, and Grzegorz P. Karwasz. "Testing an Ortec Lifetime System." Materials Science Forum 666 (December 2010): 155–59. http://dx.doi.org/10.4028/www.scientific.net/msf.666.155.

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We report preliminary performance tests of an ORTEC PLS lifetime system based on plastic scintillators and analog electronic system. A variety of samples was measured, from metals (Cu, stainless steel), across semiconductors (Cz-grown silicon, ZnSe) to nanostructured ceramics (ZrO2). All results obtained are compatible with literature reports and indicate the lifetime resolution of the whole system as 180 ps.

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Tam, C. Y., and C. H. Shek. "Effects of alloying on oxidation of Cu-based bulk metallic glasses." Journal of Materials Research 20, no. 10 (2005): 2647–53. http://dx.doi.org/10.1557/jmr.2005.0336.

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The oxidation kinetics and the effects of alloying on the oxidation behaviors of copper-based bulk metallic glasses were studied. The oxidation kinetics, oxide compositions, and structures were investigated by thermogravimetric analysis (TGA), x-ray diffraction, x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Both the TGA results and the XPS depth profile measurements showed that the oxidation resistance of Cu60Zr30Ti10 bulk metallic glass was improved by adding Hf, but it deteriorated when it was alloyed with Y. The oxide phases were found to be ZrO2, Cu2O, and CuO in samples heated at 573 K while an additional metallic Cu phase was detected in the ones heated at 773 K. A porous oxide structure was observed in the (Cu0.6Zr0.3Ti0.1)98Y2 metallic glass oxidized at 673 K, and the poor oxidation resistance of the alloy is attributed to the porous structure.

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Din, Israf Ud, Maizatul S. Shaharun, Abdul Naeem, Mshari A. Alotaibi, Abdulrahman I. Alharthi, and Qazi Nasir. "CO2 Conversion to Methanol over Novel Carbon Nanofiber-Based Cu/ZrO2 Catalysts—A Kinetics Study." Catalysts 10, no. 5 (2020): 567. http://dx.doi.org/10.3390/catal10050567.

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Ongoing industrialization has deteriorated the global environment. Global warming is a human-induced issue affecting the environment. The alarming increase in CO2 emissions is among the major contributors to global warming. The conversion of CO2 to methanol is an economically viable and environmentally friendly solution to mitigate its concentration. Here, hydrogenation of CO2 was studied over carbon nanofiber-based Cu/ZrO2 catalysts. Kinetics investigations were carried out for the reaction. Overall, kinetics data indicated that CO2 conversion follows a pseudo-first-order reaction. The kinetics studies were further modeled by using an artificial neural network, which supported the experimental kinetics study.

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Cifuentes, Bernay, Felipe Bustamante, and Martha Cobo. "Single and Dual Metal Oxides as Promising Supports for Carbon Monoxide Removal from an Actual Syngas: The Crucial Role of Support on the Selectivity of the Au–Cu System." Catalysts 9, no. 10 (2019): 852. http://dx.doi.org/10.3390/catal9100852.

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A catalytic screening was performed to determine the effect of the support on the performance of an Au–Cu based system for the removal of CO from an actual syngas. First, a syngas was obtained from reforming of ethanol. Then, the reformer outlet was connected to a second reactor, where Au–Cu catalysts supported on several single and dual metal oxides (i.e., CeO2, SiO2, ZrO2, Al2O3, La2O3, Fe2O3, CeO2-SiO2, CeO2-ZrO2, and CeO2-Al2O3) were evaluated. AuCu/CeO2 was the most active catalyst due to an elevated oxygen mobility over the surface, promoting CO2 formation from adsorption of C–O* and OH− intermediates on Au0 and CuO species. However, its lower capacity to release the surface oxygen contributes to the generation of stable carbon deposits, which lead to its rapid deactivation. On the other hand, AuCu/CeO2-SiO2 was more stable due to its high surface area and lower formation of formate and carbonate intermediates, mitigating carbon deposits. Therefore, use of dual supports could be a promising strategy to overcome the low stability of AuCu/CeO2. The results of this research are a contribution to integrated production and purification of H2 in a compact system.

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Kulesza, Pawel J., and Iwona A. Rutkowska. "(Invited) Hybrid Mixed-Metal-Oxide-Based Catalytic Systems for Efficient Electroreduction of Carbon Dioxide." ECS Meeting Abstracts MA2023-01, no. 37 (2023): 2188. http://dx.doi.org/10.1149/ma2023-01372188mtgabs.

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Of particular interest to the preparation of advanced catalytic materials is efficient utilization of nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties. There has been growing interest in the electrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large over-potentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the electrochemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered. We explore here the ability of polynuclear transition metal oxide based systems to function as cocatalysts and to stabilize and activate metal nanocenters. Here certain nanostructured metal oxides of zirconium, titanium, molybdenum or tungsten have been demonstrated to influence supported catalytic metal sites in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Ru), thus affecting their chemisorptive and catalytic properties during CO2-reduction. Metal oxide (WO3, MoO3, TiO2) nanostructures can generate highly reactive –OH groups at electrocatalytic interface. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Pd), thus affecting their chemisorptive properties. Metal oxide (ZrO2, WO3) nanospecies can generate –OH groups at electrocatalytic interface. Our electrocatalytic results with copper nanostructures over-coated with ZrO2 or WO3 nanostructures imply the systems’ improved selectivity toward CO2-reduction relative to the competitive hydrogen evolution as well as the lower tendency of copper sites to undergo poisoning.

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Cygan-Bączek, Elżbieta, Piotr Wyżga, Sławomir Cygan, Piotr Bała, and Andrzej Romański. "Improvement in Hardness and Wear Behaviour of Iron-Based Mn–Cu–Sn Matrix for Sintered Diamond Tools by Dispersion Strengthening." Materials 14, no. 7 (2021): 1774. http://dx.doi.org/10.3390/ma14071774.

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The work presents the possibility of fabricating materials for use as a matrix in sintered metallic-diamond tools with increased mechanical properties and abrasion wear resistance. In this study, the effect of micro-sized SiC, Al2O3, and ZrO2 additives on the wear behaviour of dispersion-strengthened metal-matrix composites was investigated. The development of metal-matrix composites (based on Fe–Mn–Cu–Sn–C) reinforced with micro-sized particles is a new approach to the substitution of critical raw materials commonly used for the matrix in sintered diamond-impregnated tools used for the machining of abrasive stone and concrete. The composites were prepared using spark plasma sintering (SPS). Apparent density, microstructural features, phase composition, Young’s modulus, hardness, and abrasion wear resistance were determined. An increase in the hardness and wear resistance of the dispersion-strengthened composites as compared to the base material (Fe–Mn–Cu–Sn–C) and the commercial alloy Co-20% WC provides metallic-diamond tools with high-performance properties.

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Bonamigo Moreira, Vitor, Anna Puiggalí-Jou, Emilio Jiménez-Piqué, Carlos Alemán, Alvaro Meneguzzi, and Elaine Armelin. "Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate." Materials 14, no. 4 (2021): 1043. http://dx.doi.org/10.3390/ma14041043.

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Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

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Hu, Yang, Kai Wang, Michael Müller, Egbert Wessel, and Robert Spatschek. "Theoretical Prediction of the Sublimation Behavior by Combining Ab Initio Calculations with Statistical Mechanics." Materials 16, no. 7 (2023): 2826. http://dx.doi.org/10.3390/ma16072826.

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We develop a theoretical model to predict the sublimation vapor pressure of pure substances. Moreover, we present a simple monoatomic molecule approximation, which reduces the complexity of the vapor pressure expression for polyatomic gaseous molecules at a convincing level of accuracy, with deviations of the Arrhenius prefactor for NaCl and NaF being 5.02% and 7.08%, respectively. The physical model is based on ab initio calculations, statistical mechanics, and thermodynamics. We illustrate the approach for Ni, Cr, Cu (metallic bond), NaCl, NaF, ZrO2 (ionic bond) and SiO2 (covalent bond). The results are compared against thermodynamic databases, which show high accuracy of our theoretical predictions, and the deviations of the predicted sublimation enthalpy are typically below 10%, for Cu even only 0.1%. Furthermore, the partial pressures caused by gas phase reactions are also explored, showing good agreement with experimental results.

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Gonzalez Caranton, Alberth Renne, Jose Carlos Costa da Silva Pinto, Fernando Stavale, Jade Barreto, and Martin Schmal. "Statistical analysis of the catalytic synthesis of Vinyl acetate over Pd-Cu/ZrO2 nanostructured based catalysts." Catalysis Today 344 (March 2020): 108–17. http://dx.doi.org/10.1016/j.cattod.2018.10.034.

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Din, Israf Ud, Maizatul S. Shaharun, A. Naeem, S. Tasleem, and Pervaiz Ahmad. "Revalorization of CO2 for methanol production via ZnO promoted carbon nanofibers based Cu-ZrO2 catalytic hydrogenation." Journal of Energy Chemistry 39 (December 2019): 68–76. http://dx.doi.org/10.1016/j.jechem.2019.01.023.

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Adánez-Rubio, Iñaki, S. Toufigh Bararpour, Alberto Abad, et al. "Performance Evaluation of a Cu-Based Oxygen Carrier Impregnated onto ZrO2 for Chemical-Looping Combustion (CLC)." Industrial & Engineering Chemistry Research 59, no. 15 (2020): 7255–66. http://dx.doi.org/10.1021/acs.iecr.9b05835.

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Wang, Bin, Dong Ya Huang, Zhe Chen, Nathalie Prud’homme, and Vincent Ji. "Oxidation Kinetic and Diffusion Mechanism Study of a Zr-Based Bulk Metallic Glass Alloy." Materials Science Forum 675-677 (February 2011): 193–96. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.193.

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Oxidation kinetic of a Zr55Cu30Al10Ni5 bulk metallic glass (BMG) and its crystalline counterpart were studied under dry artificial air (20% of O2 and 80% of N2) at 673 K by thermogravimetry analysis (TGA) method. According to TGA profiles, the oxidation kinetic in both amorphous and crystalline states followed a protective parabolic law. However, the oxidation rates for the amorphous alloy were obviously higher than those for the crystalline alloy. Pseudo-grazing incident X-Ray diffraction (GIXRD) has been carried out to identify the oxides nature and their crystalline structure. Tetragonal-ZrO2 dominated the oxide scale formed on both alloys (BMG and crystalline) at T = 673 K; meanwhile, a slight amount of Cu was detected on the oxide surface of studied BMG alloy. The atomic diffusion mechanism was investigated using a two-stage oxidation treatment to study oxide scale growth kinetics. The studied specimens were oxidized firstly under dry artificial air and then under 18O2 isotopic tracer gas for 1.5 hours respectively at 673 K. The evident solute penetration zone and ion diffusion characteristic through the oxide scale were determined by Cs+ secondary ion mass spectrometry (SIMS) depth profile. The results showed the mechanism of the oxide layer formation of both alloys was not only due to Oxygen ions diffusion from oxide surface to interior scale, but also to an outward diffusion of Zirconium ions from substrate to oxide layer and the ZrO2 oxide growth seemed to occur at the oxide/gas interface in our studied case.

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Yin, Wang, Maria V. Alekseeva (Bykova), Robertus Hendrikus Venderbosch, Vadim A. Yakovlev, and Hero Jan Heeres. "Catalytic Hydrotreatment of the Pyrolytic Sugar and Pyrolytic Lignin Fractions of Fast Pyrolysis Liquids Using Nickel Based Catalysts." Energies 13, no. 1 (2020): 285. http://dx.doi.org/10.3390/en13010285.

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Catalytic hydrotreatment is recognized as an efficient method to improve the properties of pyrolysis liquids (PO) to allow co-feeding with fossil fuels in conventional refinery units. The promising catalyst recipes identified so far are catalysts with high nickel contents (38 to 57 wt.%), promoted by Cu, Pd, Mo and/or a combination, and supported by SiO2, SiO2-ZrO2, SiO2-ZrO2-La2O3 or SiO2-Al2O3. To gain insights into the reactivity of the pyrolytic sugar (PS) and pyrolytic lignin (PL) fraction of PO, hydrotreatment studies (350 °C, 120 bar H2 pressure (RT) for 4 h) were performed in a batch autoclave. Catalyst performance was evaluated by considering the product properties (H/C ratio, the charring tendency (TGA) and molecular weight distribution (GPC)) and the results were compared with a benchmark Ru/C catalyst. All Ni based catalysts gave products oils with a higher H/C compared to Ru/C. The Mo promoted catalyst performed best, giving a product with the highest H/C ratio (1.54) and the lowest TG residue (0.8 wt.% compared to 12 wt.% for the fresh PS). The results further revealed that the PS fraction is highly reactive and full conversion was achieved at 350 °C. In contrast, the PL fraction was rather inert, and only part of the PL fraction was converted. The fresh and spent catalysts after the hydrotreatment of the PS and PL fractions were characterized by elemental analysis, powder X-Ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM-EDX). The results revealed that the use of PS as the feed leads to higher amounts of coke deposits on the catalysts, and higher levels of Ni agglomeration when compared to experiments with PL and pure PO. This proofs that proper catalyst selection for the PS fraction is of higher importance than for the PL fraction. The Mo promoted Ni catalysts showed the lowest amount of coke and the lowest tendency for Ni nanoparticle agglomeration compared to the monometallic Ni and bimetallic Ni-Cu catalysts.

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Guse, David, Lucas Warmuth, Moritz Herfet, et al. "Seeding as a Decisive Tool for Increasing Space-Time-Yields in the Preparation of High-Quality Cu/ZnO/ZrO2 Catalysts." Catalysts 14, no. 8 (2024): 517. http://dx.doi.org/10.3390/catal14080517.

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Aging is one of the key steps in the preparation of highly active Cu/ZnO-based catalysts for use in the production of methanol. If certain pH and temperature specifications are met, an initially amorphous precipitate transforms into the crystalline precursor phase of zincian malachite, which is characterized by a periodic arrangement of Cu and Zn atoms and has proven advantageous for the quality of the final catalyst. However, aging generally takes between 30 min and multiple hours until the desired phase transformation is completed. With our study, we show that aging can be significantly accelerated by seeding the freshly precipitated suspension with already aged zincian malachite crystals: the necessary aging time was reduced by 41% for seeding mass fractions as low as 3 wt.% and from 83 min to less than 2 min for 30 wt.% seeds. No negative influence of seeding on the phase composition, specific surface area, molar metal ratios, or the morphology of the aged precursor could be identified. Consequently, the catalyst performance in the synthesis of methanol from CO2, as well as from a CO/CO2 mixture, was identical to a catalyst from an unseeded preparation and showed small advantages compared to a commercial sample. Thus, we conclude that seeding is a vital tool to accelerate the preparation of all Cu/Zn-based catalysts while maintaining product quality, presumably also on an industrial scale.

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Maev, Roman Gr, Jimi Tjong, Eugene Leshchinsky, Mircea Pantea, and Volf Leshchynsky. "Cold-Sprayed Multilayer Thermal Barrier–Catalytic Coatings for Engine Pistons: Coatings Design and Properties." Coatings 12, no. 9 (2022): 1332. http://dx.doi.org/10.3390/coatings12091332.

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Yttrium-stabilized zirconia thermal barrier coatings (TBCs) of combustion chambers and piston crowns are used most frequently to increase the chamber temperature and the internal combustion engine efficiency. The development of multilayer metal matrix composite coating is of great importance to diminish the ceramic thermal barrier coating’s brittleness and susceptibility to degradation providing the similar thermal insulation. Our group is developing multilayer TBCs based on intermetallic (Fe-Al) compounds combined with alternating zirconia-based layers made by low-pressure cold spraying (LPCS) and sintering. The Fe-Al intermetallic phase was synthesized during reaction sintering of stainless steel and Al particles in the powder layer previously obtained by cold spraying. A double-nozzle low-pressure cold-spraying gun was used to deposit two layers (stainless steel and Al-YSZ) per one track. The effect of the breaking of the brittle ZrO2 particles due to impingement with the substrate results in the formation of a relatively homogeneous structure with ZrO2 particle size of 3–10 μm. Cold-spray deposition of additional Cu-Ni-Graphene catalytic layers on the TBCs is developed to improve performance and emissions of engines. The microstructure, thermal conductivity, thermal shock behavior and microhardness of TBCs were examined and discussed.

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Ye, Runping, Shuwei Xiao, Qinghua Lai, et al. "Advances in Enhancing the Stability of Cu-Based Catalysts for Methanol Reforming." Catalysts 12, no. 7 (2022): 747. http://dx.doi.org/10.3390/catal12070747.

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The advent of fuel cells has led to a series of studies on hydrogen production. As an excellent hydrogen carrier, methanol can be used for reforming to produce hydrogen. Copper-based catalysts have been widely used in methanol reforming due to their high catalytic activity and low-cost preparation. However, copper-based catalysts have been subjected to poor stability due to spontaneous combustion, sintering, and deactivation. Thus, the research on the optimization of copper-based catalysts is of great significance. This review analyzes several major factors that affect the stability of copper-based catalysts, and then comments on the progress made in recent years to improve the catalytic stability through various methods, such as developing preparation methods, adding promoters, and optimizing supports. A large number of studies have shown that sintering and carbon deposition are the main reasons for the deactivation of copper-based catalysts. It was found that the catalysts prepared by the modified impregnation method exhibit higher catalytic activity and stability. For the promoters and supports, it was also found that the doping of metal oxides such as MgO and bimetallic oxides such as CeO2-ZrO2 as the support could present better catalytic performance for the methanol reforming reaction. It is of great significance to discover some new materials, such as copper-based spinel oxide, with a sustained-release catalytic mechanism for enhancing the stability of Cu-based catalysts. However, the interaction mechanism between the metal and the support is not fully understood, and the research of some new material copper-based catalysts in methanol reforming has not been fully studied. These are the problems to be solved in the future.

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Kim, Chan-Joong, Ki-Baik Kim, Gye-Won Hong, and Ho-Yong Lee. "Nonuniform distribution of second phase particles in melt-textured Y–Ba–Cu–O oxide with metal oxide (CeO2, SnO2, and ZrO2) addition." Journal of Materials Research 10, no. 7 (1995): 1605–10. http://dx.doi.org/10.1557/jmr.1995.1605.

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Segregation of second-phase particles within Y1Ba2Cu3O7−y domain was investigated in melt-textured Y-Ba-Cu-O with metal oxide (CeO2, SnO2, and ZrO2) addition. It is found that coarse particles (Y2Ba1Cu1O5) are trapped with a special pattern in the interior of Y1Ba2Cu3O7−y domain, while fine BaCeO3 and BaSnO3 particles are present within the remnant liquid-phase region. During the growth of Y1Ba2Cu3O7−y domain, fine particles appear to be pushed out of the advancing Y1Ba2Cu3O7−y /liquid interface toward the liquid phase. The particle segregation that occurred during peritectic growth of the Y1Ba2Cu3O7−y domain was explained in terms of the Uhlmann-Chalmers-Jackson theory based on the particle interaction at solid/liquid interface.

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Wang, Yu Hao, Wen Gui Gao, Yan E. Zheng, and Hua Wang. "The Influence of Zn/Zr Ratios on CuO-ZnO-ZrO₂ Catalysts for Methanol Synthesis from CO₂Hydrogenation." Advanced Materials Research 941-944 (June 2014): 425–29. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.425.

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A series of CuO–ZnO–ZrO2(CZZ) catalysts with different Zn/Zr ratios were successfully prepared by the co-precipitation method and characterized by the techniques of X-ray diffraction (XRD), N2adsorption, reactive N2O adsorption, H2temperature-programmed reduction (H2-TPR). The catalytic activities of the catalysts were tested for methanol synthesis from CO2hydrogenation. It was found that the increasing of the Zn/Zr ratio could lead to the increase of the crystallite size of metallic oxide. When the amount of ZnO ranged from 20% to 80%, the CZZ catalysts exhibited a better activity. It revealed that both Zn and Zr were important parameter for Cu-based catalysts, which were interacted with each other.

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Labisz, Krzysztof, Tomasz Tański, Beata Krupińska, Mariusz Krupiński, and Wojciech Pakieła. "HPDL Laser Alloying of Al-Si-Cu Alloy with ZrO₂ Powder." Advanced Materials Research 1036 (October 2014): 434–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1036.434.

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The purpose of this paper was the investigation of laser treatment influence on the microstructure and properties of the surface layer of heat treated Al-Si-Cu cast aluminium alloys, using the high power diode laser (HPDL). The performed laser treatment involves remelting and feeding of ZrO2 ceramic powder into the aluminium surface. Based on the performed investigations it was possible to obtain the layer consisting of the heat affected zone, transition zone and remelted zone, without cracks and defects as well as has with a slightly higher hardness value compared to the non remelted material. The laser power range was chose as 1.5 to 2.0 kW and implicated by one process speed rate of 0.25 m/min. Also a powder size was used for alloying with the particle size of ca. 100 μm. The hardness value increases according to the laser power used so that the highest power applied gives to highest hardness value in the remelted layer [1-8]. The carried out investigations allow to conclude, that as a result of alloying of the heat-treated cast aluminium alloys with oxide ceramic powder the surface layer can be enriched with the powder particle and in some cases a high-quality top layer is possible to obtain. Very often to determine conditions of laser treatment are being used the numerical methods that would significantly shorten the time to find the most optimal parameters. [8]. Concerning original practical implications of this work there was important to investigate the appliance possibility of High Power Diode Laser (HPDL) for enhancement of the aluminium surface properties, especially the wear resistance and hardness. the scientific reason was also to describe structure changes and processes occurred in the laser remelted surface aluminium layer after ZrO2 feeding using HPDL laser [10-1. .

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Díez-Martín, Laura, Gemma Grasa, Ramón Murillo, Andrew Scullard, and Gareth Williams. "Development of Suitable CuO-Based Materials Supported on Al2O3, MgAl2O4, and ZrO2 for Ca/Cu H2 Production Process." Industrial & Engineering Chemistry Research 57, no. 8 (2018): 2890–904. http://dx.doi.org/10.1021/acs.iecr.7b05103.

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35

Secci, Fausto, Marco Sanna Angotzi, Valentina Mameli та ін. "Mesostructured γ-Al2O3-Based Bifunctional Catalysts for Direct Synthesis of Dimethyl Ether from CO2". Catalysts 13, № 3 (2023): 505. http://dx.doi.org/10.3390/catal13030505.

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In this work, we propose two bifunctional nanocomposite catalysts based on acidic mesostructured γ-Al2O3 and a Cu/ZnO/ZrO2 redox phase. γ-Al2O3 was synthesized by an Evaporation-Induced Self-Assembly (EISA) method using two different templating agents (block copolymers Pluronic P123 and F127) and subsequently functionalized with the redox phase using an impregnation method modified with a self-combustion reaction. These nanocomposite catalysts and their corresponding mesostructured supports were characterized in terms of structural, textural, and morphological features as well as their acidic properties. The bifunctional catalysts were tested for the CO2-to-DME process, and their performances were compared with a physical mixture consisting of the most promising support as a dehydration catalyst together with the most common Cu-based commercial redox catalyst (CZA). The results highlight that the most appropriate Pluronic for the synthesis of γ-Al2O3 is P123; the use of this templating agent allows us to obtain a mesostructure with a smaller pore size and a higher number of acid sites. Furthermore, the corresponding composite catalyst shows a better dispersion of the redox phase and, consequently, a higher CO2 conversion. However, the incorporation of the redox phase into the porous structure of the acidic support (chemical mixing), favoring an intimate contact between the two phases, has detrimental effects on the dehydration performances due to the coverage of the acid sites with the redox nanophase. On the other hand, the strategy involving the physical mixing of the two phases, distinctly preserving the two catalytic functions, assures better performances.

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Bączek, Elżbieta. "Technological properties of metallic-diamond tools manufactured by SPS process." Mechanik 91, no. 12 (2018): 1140–43. http://dx.doi.org/10.17814/mechanik.2018.12.204.

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This paper presents the results of the technological properties of impregnated diamond tools fabricated via spark plasma sintering (SPS) during the process of grinding and cutting of highpurity oxides ceramics (ZrO2) stabilized with Y2O3 or MgO. As a metal matrix the water atomized tin bronze and steel-based matrix was used. After sintering, an analysis of microstructure was conducted using scanning electron microscopy. The resulting materials were tested for the apparent density determined by Archimedes’ method, Rockwell hardness (scale B), Young’s modulus, as well as for the technological properties. The performance results of obtained diamond composites were compared with commercial diamond wheel fabricated by HP (hot pressing), usually employed in the grinding of ceramics. Results showed that diamond tools based on Cu-Sn and steel, obtained by SPS, may be successfully used as a matrix in the impregnated diamond tools for cutting or grinding of high-purity oxides ceramics.

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Doggali, Pradeep, Y. Teraoka, P. Mungse, Irfan K. Shah, S. Rayalu, and Nitin Labhsetwar. "Combustion of volatile organic compounds over Cu–Mn based mixed oxide type catalysts supported on mesoporous Al2O3, TiO2 and ZrO2." Journal of Molecular Catalysis A: Chemical 358 (June 2012): 23–30. http://dx.doi.org/10.1016/j.molcata.2012.02.004.

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38

Van Driessche, I., D. Depla, J. Denul, N. De Roo, R. Gryse, and S. Hoste. "Superconducting thick films based on Bi-Pb-Sr-Ca-Cu Nitrate pastes, screen printed on alumina and ZrO2 buffered alumina." Applied Superconductivity 2, no. 6 (1994): 391–400. http://dx.doi.org/10.1016/0964-1807(94)90086-8.

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39

Din, Israf Ud, Maizatul S. Shaharun, A. Naeem, Mshari A. Alotaibi, Abdulrahman I. Alharthi, and Qazi Nasir. "Effect of reaction conditions on the activity of novel carbon nanofiber-based Cu/ZrO2 catalysts for CO2 hydrogenation to methanol." Comptes Rendus. Chimie 23, no. 1 (2020): 57–61. http://dx.doi.org/10.5802/crchim.6.

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40

Rabiezadeh, Amin, and Saman Ghafaei. "The influence of multi-pass friction stir processing on microstructure and sliding wear behavior of Cu/ZrO2 surface composite." International Journal of Materials Research 111, no. 10 (2020): 814–25. http://dx.doi.org/10.1515/ijmr-2020-1111005.

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Abstract In this study, copper/ZrO2 surface composites were produced using nano-particles via friction stir processing in order to enhance surface tribological properties. The present research aimed to generate copper matrix composites and analyze the effect of processing parameters on the evolving microstructure, microhardness, and wear-resistance behavior. It is worth noting that the processed composite layer had more homogeneity in the four-pass process. In comparison to the base metal and non-powder samples, it had higher mechanical characteristics. Based on the results, the highest recorded hardness, approximately 288 HV, was found in a four-pass state with powder. Remarkably, it showed a double peak compared to 80 HV in the base metal. The lowest friction coefficient of four-passes with the powder sample was about 0.47, which showed a significant efficiency in comparison to the friction coefficient of base metal that was about 0.81.

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41

Bhatt, Sandhya, Raghuvesh Kumar, and Munish Kumar. "Specific heat and thermal conductivity of nanomaterials." Modern Physics Letters B 31, no. 02 (2017): 1750011. http://dx.doi.org/10.1142/s0217984917500117.

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A model is proposed to study the size and shape effects on specific heat and thermal conductivity of nanomaterials. The formulation developed for specific heat is based on the basic concept of cohesive energy and melting temperature. The specific heat of Ag and Au nanoparticles is reported and the effect of size and shape has been studied. We observed that specific heat increases with the reduction of particle size having maximum shape effect for spherical nanoparticle. To provide a more critical test, we extended our model to study the thermal conductivity and used it for the study of Si, diamond, Cu, Ni, Ar, ZrO2, BaTiO3 and SrTiO3 nanomaterials. A significant reduction is found in the thermal conductivity for nanomaterials by decreasing the size. The model predictions are consistent with the available experimental and simulation results. This demonstrates the suitability of the model proposed in this paper.

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Hussain, Sajid, Eleonora Aneggi, Alessandro Trovarelli, and Daniele Goi. "Removal of Organics from Landfill Leachate by Heterogeneous Fenton-like Oxidation over Copper-Based Catalyst." Catalysts 12, no. 3 (2022): 338. http://dx.doi.org/10.3390/catal12030338.

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Landfill leachates are a mixture of high concentration organic and inorganic contaminants and need to be appropriately treated due to their toxicity and severe adverse effects on the environment. Here, we studied the treatment of landfill leachate through a heterogeneous Fenton-like oxidation process using a zirconia supported copper catalyst (Cu/ZrO2). Reaction conditions such as pH, amount of catalyst, oxidant dose, temperature, and reaction time were investigated and their effects on pollutant abatement discussed. AOS (average oxidation state) and COS (carbon oxidation state) parameters were used for the evaluation of the degree of oxidation of the process, obtaining some insight into the formation of oxidized intermediates (partial oxidation) and the total oxidation (mineralization) of the leachate during the reaction. A two-step oxidation process enhanced the overall performance of the reaction with an abatement of organic compounds of 92% confirming the promising activity of a copper-based catalyst for the treatment of liquid waste. Higher catalytic activity was achieved when the following reaction conditions were applied: 70 °C, pH 5, 200 mg/L of catalyst, 30 mL/L of H2O2 dose, and 150 min. In addition, durability of the catalyst under optimized reaction conditions was verified by repeated reaction cycles.

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Ishutin, I. A., A. A. Chepurov, and E. I. Zhimulev. "Experimental Study of Surface Etching in Synthetic Diamond Microcrystals due to Presence of Cu and Fe at High Pressure." Izvestiya of Altai State University, no. 1(111) (March 6, 2020): 18–21. http://dx.doi.org/10.14258/izvasu(2020)1-02.

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In the present work, microcrystals of synthetic diamond extracted from a metal-diamond composite were investigated. A composite based on Cu and Fe was obtained by sintering at a pressure of 4 GPa and a temperature of1300 °C. The experiments were carried out using a split-sphere high-pressure apparatus BARS. The high-pressure cell was made of refractory oxides ZrO2, CaO, and MgO using a tubular graphite heater. In the composite, diamond grains were in close contact with neighboring diamonds, and the metal phase filled the interstices. The study of the diamond crystals demonstrated the appearance of newly formed micromorphological structures on the surfaces in the form of numerous cavities of irregular shape on the faces of octahedron, as well as pyramids on the faces of cube, the morphological elements of which follow the contours of the cube face of the diamond. Thus, the results of the work evidence for the processes of etching of the diamond crystals during the experiments, which is associated with the presence of metallic iron in the composite. This type of etching forms a roughly cavernous surface on the diamond crystals, which can be considered as an additional factor for improving the metal-diamond bond in copper-based composites.

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Yakoumis, Iakovos, Εkaterini Polyzou, and Anastasia Maria Moschovi. "PROMETHEUS: A Copper-Based Polymetallic Catalyst for Automotive Applications. Part II: Catalytic Efficiency an Endurance as Compared with Original Catalysts." Materials 14, no. 9 (2021): 2226. http://dx.doi.org/10.3390/ma14092226.

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PROMETHEUS catalyst, a copper-based polymetallic nano-catalyst has been proven to be suitable for automotive emission control applications. This novel catalyst consists of copper, palladium and rhodium nanoparticles as active phases, impregnated on an inorganic oxide substrate, CeO2/ZrO2 (75%, 25%). The aim of PROMETHEUS catalyst’s development is the substitution of a significant amount (85%) of Platinum Group Metals (PGMs) with copper nanoparticles while, at the same time, presenting high catalytic efficiency with respect to the commercial catalysts. In this work, an extensive investigation of the catalytic activity of full scale PROMETHEUS fresh and aged catalyst deposited on ceramic cordierites is presented and discussed. The catalytic activity was tested on an Synthetic Gas Bench (SGB) towards the oxidation of CO and CH4 and the reduction of NO. The loading of the washcoat was 2 wt% (metal content) on Cu, Pd, Rh with the corresponding metal ratio at 21:7:1. The concentration of the full-scale monolithic catalysts to be 0.032% total PGM loading for meeting Euro III standard and 0.089% for meeting Euro IV to Euro VIb standards. The catalytic activity of all catalysts was tested both in rich-burn (λ = 0.99) and lean-burn conditions (λ = 1.03).

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45

Soto Beobide, Amaia, Anastasia M. Moschovi, Georgios N. Mathioudakis, et al. "High Catalytic Efficiency of a Nanosized Copper-Based Catalyst for Automotives: A Physicochemical Characterization." Molecules 27, no. 21 (2022): 7402. http://dx.doi.org/10.3390/molecules27217402.

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The global trend in restrictions on pollutant emissions requires the use of catalytic converters in the automotive industry. Noble metals belonging to the platinum group metals (PGMs, platinum, palladium, and rhodium) are currently used for autocatalysts. However, recent efforts focus on the development of new catalytic converters that combine high activity and reduced cost, attracting the interest of the automotive industry. Among them, the partial substitution of PGMs by abundant non-PGMs (transition metals such as copper) seems to be a promising alternative. The PROMETHEUS catalyst (PROM100) is a polymetallic nanosized copper-based catalyst for automotives prepared by a wet impregnation method, using as a carrier an inorganic mixed oxide (CeO2-ZrO2) exhibiting elevated oxygen storage capacity. On the other hand, catalyst deactivation or ageing is defined as the process in which the structure and state of the catalyst change, leading to the loss of the catalyst’s active sites with a subsequent decrease in the catalyst’s performance, significantly affecting the emissions of the catalyst. The main scope of this research is to investigate in detail the effect of ageing on this low-cost, effective catalyst. To that end, a detailed characterization has been performed with a train of methods, such as SEM, Raman, XRD, XRF, BET and XPS, to both ceria–zirconia mixed inorganic oxide support (CZ-fresh and -aged) and to the copper-based catalyst (PROM100-fresh and -aged), revealing the impact of ageing on catalytic efficiency. It was found that ageing affects the Ce–Zr mixed oxide structure by initiating the formation of distinct ZrO2 and CeO2 structures monitored by Raman and XRD. In addition, it crucially affects the morphology of the sample by reducing the surface area by a factor of nearly two orders of magnitude and increasing particle size as indicated by BET and SEM due to sintering. Finally, the Pd concentration was found to be considerably reduced from the material’s surface as suggested by XPS data. The above-mentioned alterations observed after ageing increased the light-off temperatures by more than 175 °C, compared to the fresh sample, without affecting the overall efficiency of the catalyst for CO and CH4 oxidation reactions. Metal particle and CeZr carrier sintering, washcoat loss as well as partial metal encapsulation by Cu and/or CeZrO4 are identified as the main causes for the deactivation after hydrothermal ageing.

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Cui, Yuanyuan, Chao Wen, Xi Chen, and Wei-Lin Dai. "Highly selective one-pot continuous synthesis of 2-methoxyethanol via hydrogenation of dimethyl oxalate on Cu/ZrO2 catalysts with balanced acid sites." RSC Adv. 4, no. 59 (2014): 31162–65. http://dx.doi.org/10.1039/c4ra05014b.

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The distribution of 2-methoxyethanol and ethylene glycol can be controlled by regulating the surface acidity of copper based zirconia catalysts for hydrogenation of dimethyl oxalate. The yield of 2-methoxyethanol can reach 68% due to the synergistic effect of the surface acid site and active copper site.

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Khodabandeh, Hamideh, Ali Nakhaei Pour, and Ali Mohammadi. "Role of WO3 loading in the hydrogenation of CO2 to methanol by CeO2−ZrO2−WO3 supported Cu-based catalysts: Experimental and DFT studies." International Journal of Hydrogen Energy 100 (January 2025): 1063–74. https://doi.org/10.1016/j.ijhydene.2024.12.393.

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48

Kustov, A. L., S. B. Rasmussen, R. Fehrmann, and P. Simonsen. "Activity and deactivation of sulphated TiO2- and ZrO2-based V, Cu, and Fe oxide catalysts for NO abatement in alkali containing flue gases." Applied Catalysis B: Environmental 76, no. 1-2 (2007): 9–14. http://dx.doi.org/10.1016/j.apcatb.2007.05.004.

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Alvi, Sajid Ali, Andrea Fazi, Olof Bäcke, et al. "Nano-Level Homogeneity of SiGe-Cu Composite Anodes." ECS Meeting Abstracts MA2024-02, no. 4 (2024): 445. https://doi.org/10.1149/ma2024-024445mtgabs.

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Employing alloy anodes based on Si, Ge, Sn, etc. can increase the energy density of lithium-ion batteries (LIBs) by their high gravimetric capacity.1 Their large volumetric expansion during lithiation, however, leads to cracks and solid electrolyte interphase (SEI) breakdown, followed by pulverization.2 Alloy engineering, creating composite alloys via ball milling of e.g. an active Si-phase embedded in an inactive matrix to buffer volume expansion, is one alternative approach/remedy.3-6 But the homogeneity of the alloy created varies with the processing conditions, such as the ball milling material (steel/WC/ZrO2), speed and duration, as well as the diameter and number of balls. As proof-of-concept and to learn more about the dependency on high-energy ball milling conditions, we have here synthesized SiGeCu (SGC) composite alloy anodes. Cu forms in situ Cu3Ge, which enhances electrical conductivity and acts as the buffer phase for SiGe. Atom probe tomography (APT) is used to quantify the nano-level homogeneity, and this is correlated vs. the electrochemical performance in LIB half-cells of Li/1 M LP57 + 10% FEC/SGC, with the composite anode subject to different ball milling durations. The shorter duration (40 h) leads to formation of an isolated Si-phase (Figure 1a) and this half-cell has quite different characteristics as compared to the half-cell when only SiGe and Cu3Ge phases are formed (longer duration, 60 h) (Figure 1b) – especially w r t the reproducibility of the capacity, proving the role and importance of nano-level homogeneity. Figure 1: a) the isolated Si-phase as revealed by APT, and b) cycling data for the Li/1 M LP57 + 10% FEC/SGC half-cells – two for each ball-milling duration produced SGC. References (1) Wang, X.; Tang, S.; Guo, W.; Fu, Y.; Manthiram, A. Advances in Multimetallic Alloy-Based Anodes for Alkali-Ion and Alkali-Metal Batteries. Materials Today 2021, 50 (November), 259–275. (2) Eshetu, G. G.; Zhang, H.; Judez, X.; Adenusi, H.; Armand, M.; Passerini, S.; Figgemeier, E. Production of High-Energy Li-Ion Batteries Comprising Silicon-Containing Anodes and Insertion-Type Cathodes. Nat Commun 2021, 12 (1), 1–14. (3) Ruttert, M.; Siozios, V.; Winter, M.; Placke, T. Mechanochemical Synthesis of Fe-Si-Based Anode Materials for High-Energy Lithium Ion Full-Cells. ACS Appl Energy Mater 2020, 3 (1), 743–758. (4) Nuhu, B. A.; Bamisile, O.; Adun, H.; Abu, U. O.; Cai, D. Effects of Transition Metals for Silicon-Based Lithium-Ion Battery Anodes: A Comparative Study in Electrochemical Applications. J Alloys Compd 2023, 933. (5) Liu, H.; Long, Y.; Chen, Y.; Wang, Z.; Zhang, C.; Hu, R.; Zhang, X.; Yu, P. Tuning Inactive Phases in Si-Ti-B Ternary Alloy Anodes to Achieve Stable Cycling for High-Energy-Density Lithium-Ion Batteries. ACS Appl Mater Interfaces 2021, 13 (48), 57317–57325. (6) Zhang, X.; Wang, L.; Zheng, T.; Lam, K. Si/CrSi2 Alloy Anodes Synthesized by a High-Energy Ball-Milling for Lithium-Ion Batteries: Microstructure, Electrochemistry, and Carbon Coating. Energy Fuels 2023, 37 (15), 11419–11431. Figure 1

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Volosova, Marina A., Anna A. Okunkova, Sergey V. Fedorov, Khaled Hamdy, and Mariya A. Mikhailova. "Electrical Discharge Machining Non-Conductive Ceramics: Combination of Materials." Technologies 8, no. 2 (2020): 32. http://dx.doi.org/10.3390/technologies8020032.

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One of the promising processing methods for non-conductive structural and functional ceramics based on ZrO2, Al2O3, and Si3N4 systems is electrical discharge machining with the assistance of an auxiliary electrode that can be presented in the form of conductive films with a thickness up to 4–10 µm or nanoparticles - granules, tubes, platelets, multidimensional particles added in the working zone as a free poured powder the proper concentration of which can be provided by ultrasound emission or by dielectric flows or as conductive additives in the structure of nanocomposites. However, the described experimental approaches did not reach the production market and industry. It is related mostly to the chaotic development of the knowledge and non-systematized data in the field when researchers often cannot ground their choice of the material for auxiliary electrodes, assisting powders, or nano additives or they cannot explain the nature of processes that were observed in the working tank during experiments when their results are not correlated to the measured specific electrical conductivity of the electrodes, particles, ceramic workpieces or nanocomposites but depends on something else. The proposed review includes data on the main electrophysical and chemical properties of the components in the presence of heat when the temperature in the interelectrode gap reaches 10,000 °C, and the systematization of data on ceramic pressing methods, including spark plasma sintering, the chemical reactions that occur in the interelectrode gap during sublimation of primary (brass and copper) and auxiliary electrodes made of transition metals Ti, Cr, Co, and carbon, auxiliary electrodes made of metals with low melting point Zn, Ag, Au, Al, assisting powder of oxide ceramics TiO2, CeO2, SnO2, ITO, conductive additives Cu, W, TiC, WC, and components of Al2O3 and Zr2O workpieces in interaction with the dielectric fluid - water and oil/kerosene medium.

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