Статті в журналах: "Cerium-oxide Based Catalyst"

1

Flytzani-Stephanopoulos, Maria. "Nanostructured Cerium Oxide “Ecocatalysts”." MRS Bulletin 26, no. 11 (November 2001): 885–89. http://dx.doi.org/10.1557/mrs2001.229.

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Catalysts based on cerium oxide are now used as effective oxidation systems in numerous environmental applications. Cerium oxide was introduced into the catalysis field relatively recently, in 1976, and not as a catalyst initially. Rather, it was chosen as the key oxygen-storage component of the three-way catalyst (TWC) used in automotive exhausts. Accordingly, ceria is used to extend the air/fuel ratio window in the exhaust gas, releasing or accepting oxygen, respectively, under fuel-rich or fuellean conditions, so that the noble metal catalyst operates at the desirable stoichiometric air/fuel ratio, at which it effectively converts all three gaseous pollutants—CO, hydrocarbons, and NO—to innocuous products. A solid solution of cerium and zirconium oxides is used in today's catalytic converters because of its higher oxygen-storage capacity (OSC) compared with pure ceria. In the years that followed the introduction of ceria into the catalytic converter, many additional merits of cerium oxide were realized, first as an active catalytic component of the TWC and subsequently as a catalyst and sorbent in various industrial applications. A review article by Trovarelli on ceria-based catalysts is a good recent compilation.

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Yuldashev, Khayot Khurmatovich, Yulbarsxon Nabievich Mansurov, Abdulaziz Ilkhomjon ugli Jurayev, and Navruzbek Abdullayevich Mirzayev. "MODERN CATALYST BASED ON CERIUM OXIDE." Theoretical & Applied Science 103, no. 11 (November 30, 2021): 940–47. http://dx.doi.org/10.15863/tas.2021.11.103.112.

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3

Brazdil, James F. "The Emergence of the Ubiquity of Cerium in Heterogeneous Oxidation Catalysis Science and Technology." Catalysts 12, no. 9 (August 29, 2022): 959. http://dx.doi.org/10.3390/catal12090959.

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Research into the incorporation of cerium into a diverse range of catalyst systems for a wide spectrum of process chemistries has expanded rapidly. This has been evidenced since about 1980 in the increasing number of both scientific research journals and patent publications that address the application of cerium as a component of a multi-metal oxide system and as a support material for metal catalysts. This review chronicles both the applied and fundamental research into cerium-containing oxide catalysts where cerium’s redox activity confers enhanced and new catalytic functionality. Application areas of cerium-containing catalysts include selective oxidation, combustion, NOx remediation, and the production of sustainable chemicals and materials via bio-based feedstocks, among others. The newfound interest in cerium-containing catalysts stems from the benefits achieved by cerium’s inclusion, which include selectivity, activity, and stability. These benefits arise because of cerium’s unique combination of chemical and thermal stability, its redox active properties, its ability to stabilize defect structures in multicomponent oxides, and its propensity to stabilize catalytically optimal oxidation states of other multivalent elements. This review surveys the origins and some of the current directions in the research and application of cerium oxide-based catalysts.

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4

Li, Tong, Zhibo Wang, Yue Shi, and Xiaolong Yao. "Preparation and Performance of Carbon-Based Ce-Mn Catalysts for Efficient Degradation of Acetone at Low Temperatures." International Journal of Environmental Research and Public Health 19, no. 24 (December 15, 2022): 16879. http://dx.doi.org/10.3390/ijerph192416879.

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Based on the porous carbon material from citric acid residue, catalysts of different Ce-Mn ratios were prepared with incipient-wetness impregnation (IWI) to delve into their acetone-degrading performance and relevant mechanisms. When the Ce-Mn molar ratio is 0.8, the prepared catalyst Ce0.8-Mn/AC shows abundant and uniformly dispersed Mn and Ce particles on the surface. The content of Mn and Ce on the Ce0.8-Mn/AC surface reaches 5.64% and 0.75%, respectively. At the acetone concentration of 238 mg/m3 (100 ppm), the laws of acetone degradation in different catalysts at different catalyzing temperatures and with various oxygen concentrations were studied, and we found that the rate of acetone degradation by Ce0.8-Mn/AC can exceed 90% at 250 °C. Cerium oxide and manganese oxide are synergistic in the catalytic degradation of acetone. Adding cerium to manganese-based catalysts can increase the oxygen migration rate in the catalysts and thus raise the reduction rate of lattice oxygen in manganese oxide. The results offer new ideas and approaches for the efficient and comprehensive utilization of bio-fermentation by-products, and for the development of cheap and high degradation performance catalysts for acetone.

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Manan, Wan Nabilah, Wan Nor Roslam Wan Isahak, and Zahira Yaakob. "CeO2-Based Heterogeneous Catalysts in Dry Reforming Methane and Steam Reforming Methane: A Short Review." Catalysts 12, no. 5 (April 19, 2022): 452. http://dx.doi.org/10.3390/catal12050452.

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Transitioning to lower carbon energy and environment sustainability requires a reduction in greenhouse gases such as carbon dioxide (CO2) and methane (CH4) that contribute to global warming. One of the most actively studied rare earth metal catalysts is cerium oxide (CeO2) which produces remarkable improvements in catalysts in dry reforming methane. This paper reviews the management of CO2 emissions and the recent advent and trends in bimetallic catalyst development utilizing CeO2 in dry reforming methane (DRM) and steam reforming methane (SRM) from 2015 to 2021 as a way to reduce greenhouse gas emissions. This paper focus on the identification of key trends in catalyst preparation using CeO2 and the effectiveness of the catalysts formulated.

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Zhao, Hai, You Ning Xu, and Jun Qing Liu. "Selective Catalytic Reduction of Nitric Oxide with Fe-Mn-Ce Metal Oxide-Based Catalysts." Advanced Materials Research 304 (July 2011): 31–35. http://dx.doi.org/10.4028/www.scientific.net/amr.304.31.

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Nanosized cerium-manganese ferrite particles were prepared by co-precipitation approach. The structural evolutions and morphological characteristics of the nanopowder were investigated using X-ray diffractometry, transmission electron microscopy and thermo-gravimetry. XRD results showed that particles with crystallite size in nanometer scale were formed. TEM studies showed the morphology of the prepared cerium-manganese ferrite with a crystallite diameter of 20 nm at the calcination temperature of 500°C for 4 h. The catalyst showed high activities for SCR of nitric oxide with ammonia.

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7

Chen, Zhu, Coleman X. Kronawitter, Xiaofang Yang, Yao-wen Yeh, Nan Yao, and Bruce E. Koel. "The promoting effect of tetravalent cerium on the oxygen evolution activity of copper oxide catalysts." Physical Chemistry Chemical Physics 19, no. 47 (2017): 31545–52. http://dx.doi.org/10.1039/c7cp05248k.

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8

Agnihotri, Ruchika, and Charlie Oommen. "Cerium oxide based active catalyst for hydroxylammonium nitrate (HAN) fueled monopropellant thrusters." RSC Advances 8, no. 40 (2018): 22293–302. http://dx.doi.org/10.1039/c8ra02368a.

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9

Mat Rosid, Salmiah Jamal, Wan Azelee Wan Abu Bakar, and Rusmidah Ali. "Catalytic CO₂/H₂ Methanation Reaction over Alumina Supported Manganese/Cerium Oxide Based Catalysts." Advanced Materials Research 1107 (June 2015): 67–72. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.67.

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The methanation reaction is a promising method for the purification of natural gas, in which the acid gases of CO2,is eliminated by catalytic conversion. The advantage of catalytic technology is the utilization of CO2present in the production of methane gas. The used of alumina supported cerium oxide as the based catalyst in CO2/H2methanation reaction have been investigated in this research by using manganese as the dopant and ruthenium as the co-dopantviawet impregnation technique. The series of cerium oxide catalysts were calcined at 400 °C for 5 hours had been prepared at the screening stage. Then, the catalysts were optimized by different calcination temperatures and different based oxide loadings. The potential catalysts of Ru/Mn/Ce (5:35:60)/Al2O3calcined at 700 °C gave 100 % of CO2conversion by using FTIR and yielded about 24 % of CH4respectively at reaction temperature of 400 °C. X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) showed that the supported catalysts were amorphous in structure. FESEM analysis illustrated the surface of the catalysts were covered with small and dispersed spherical particles. EDX analysis revealed that there was 1.02 % reduction of Ru in the Ru/Mn/Ce (5:35:60)/Al2O3used catalysts compared to fresh catalysts. Meanwhile NA analysis showed that Ru/Mn/Ce (5:35:60)/Al2O3catalysts attained surface area of 143.10 m2/g respectively.

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10

Karthickeyan, V., and P. Arulraj. "Experimental Investigation on Emission Characteristics of Catalytic Converter Using Different Wash Coat Material." Applied Mechanics and Materials 550 (May 2014): 62–70. http://dx.doi.org/10.4028/www.scientific.net/amm.550.62.

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Almost all automobiles in the world are emitting a huge amount of exhaust gases to the atmosphere every day. These exhaust gas contains harmful substances like carbon monoxide, oxides of nitrogen, hydrocarbons, and other toxic substances. If these substances go on increasing they will cause several diseases like blood circulatory problem, lung diseases, bronchitis, blood cancer, etc. Also they may cause different environmental problems like acid rain, green house effect, etc. So, the emission of these substances should be controlled as far as possible. This project work presents a new catalytic converter to be used for compressed ignition engine. The catalytic converter is developed based on the catalyst materials consisting of metal oxides such as aluminum oxide and cerium oxide coated with wire mesh filter. Both the catalyst materials - aluminum oxide and cerium oxide are inexpensive in comparison with conventional catalysts such as palladium or platinum. The main objective of this work is to control the NOx, CO emission and to develop a low-cost three way catalytic converter. This catalytic converter is assembled in the exhaust manifold region of a computerized single cylinder four stroke diesel engine.

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11

Samotaev, Nikolay, and Alexey Vasiliev. "Mixed Cerium/Zirconium Oxide as a Material for Carbon Monoxide Thermocatalytic Gas Sensor." Proceedings 2, no. 13 (December 4, 2018): 841. http://dx.doi.org/10.3390/proceedings2130841.

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The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that the application of these catalysts leads to the ambiguity of sensor response (light-off effect). It was demonstrated that a catalyst based on CeO2/ZrO2 carrier could be used for the fabrication of sensors characterized by the univocal correspondence between CO concentration and sensor response. The developed model of the CO oxidation on all Pd catalysts with inert carrier enabled the description of the CO oxidation using a single value of activation energy.

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CHEN, CHENG HAN, YUH-JING CHIOU, WEI JEN LIOU, WEI SYUAN LIN, HONG MING LIN, SHE HUANG WU, ANDRZEJ BORODZIŃSKI, PIOTR KEDZIERZAWSKI, LESZEK STOBINSKI, and SHU HUA CHIEN. "SYNTHESIS AND ELECTROCATALYSIS APPLICATION OF HYBRID PLATINUM/CERIUM OXIDE/MULTI-WALLED CARBON NANOTUBES." Functional Materials Letters 04, no. 03 (September 2011): 295–98. http://dx.doi.org/10.1142/s1793604711002032.

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The hybrid nanomaterials of platinum/cerium oxide/multi-walled carbon nanotubes ( Pt/CeO2 /MWCNTs) are synthesized successfully via impregnation and polyol processes. MWCNTs serve as an excellent supporter where CeO2 nanoparticles are decorated with well-distributed Pt nanoparticles. Images show the average particle size of crystalline Pt and CeO2 on MWCNTs are 3–7 and 20–30 nm, respectively. In electrochemical reaction, the redox peak of Pt/CeO2 -700°C/MWCNTs reveals lower potential and higher current density in methanol electro-oxidation than those of other Pt -based ones. The study indicates that the cerium oxide in Pt/CeO2 -700°C/MWCNTs catalyst will enhance significantly the oxygen ions transportation between the interface of Pt and MWCNTs to eliminate the CO poison effect on Pt catalyst.

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13

Guerrero-Torres, Antonio, Carmen Jiménez-Gómez, Juan Cecilia, Cristina García-Sancho, José Quirante-Sánchez, Josefa Mérida-Robles, and Pedro Maireles-Torres. "Influence of the Incorporation of Basic or Amphoteric Oxides on the Performance of Cu-Based Catalysts Supported on Sepiolite in Furfural Hydrogenation." Catalysts 9, no. 4 (March 31, 2019): 315. http://dx.doi.org/10.3390/catal9040315.

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Cu-based catalysts supported on sepiolite have been tested in vapor-phase hydrogenation of furfural. The incorporation of basic or amphoteric metal oxides (magnesium oxide, zinc oxide, or cerium oxide) improves the catalytic behavior, reaching a maximum furfural conversion above 80% after 5 h of reaction at 210 °C. In all cases, the main product is furfuryl alcohol, obtaining 2-methylfuran in lower proportions. The incorporation of these metal oxide species ameliorates the dispersion of metallic Cu nanoparticles, increasing the number of available Cu0-sites, which enhances the catalytic performance. The presence of acid sites favors the hydrogenolysis of furfuryl alcohol towards 2-methylfuran, although it also causes an increase of carbon species on its surface, which is associated with the catalytic deactivation of the catalyst along the time-on-stream.

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14

Mat Rosid, Salmiah Jamal, Wan Azelee Wan Abu Bakar, Susilawati Toemen, Nurulhuda Mohamad Yusoff, Azman Azid, and Wan Nur Aini Wan Mokhtar. "Investigation of active species in methanation reaction over cerium based loading." Malaysian Journal of Fundamental and Applied Sciences 15, no. 2-1 (May 15, 2019): 319–23. http://dx.doi.org/10.11113/mjfas.v15n2-1.1555.

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A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis.

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15

Naydenov, Anton, Ralitsa Velinova, Jean-Luc Blin, Laure Michelin, Bénédicte Lebeau, Hristo Kolev, Yordanka Karakirova, et al. "Reaction Kinetics and Mechanism of VOCs Combustion on Mn-Ce-SBA-15." Catalysts 12, no. 6 (May 26, 2022): 583. http://dx.doi.org/10.3390/catal12060583.

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A propane combustion catalyst based on Mn and Ce and supported by SBA-15 was prepared by the “two-solvents” method aiming at the possible application in catalytic converters for abatement of alkanes in waste (exhaust) gases. The catalyst characterization was carried out by SAXS, N2-physisorption, XRD, TEM, XPS, EPR and H2-TPR methods. The catalysts’ performance was evaluated by tests on the combustion of methane, propane and butane. The reaction kinetics investigation showed that the reaction orders towards propane and oxygen were 0.7 and 0.1, respectively. The negative reaction order towards the water (−0.3) shows an inhibiting effect on the water molecules. Based on the data from the instrumental methods, catalytic experiments and mathematic modeling of the reaction kinetics, one may conclude that the Mars–van Krevelen type of mechanism is the most probable for the reaction of complete propane oxidation over single Mn and bi-component Mn-Ce catalysts. The fine dispersion of manganese and cerium oxide and their strong interaction inside the channels of the SBA-15 molecular sieve leads to the formation of difficult to reduce oxide phases and consequently, to lower catalytic activity compared to the mono-component manganese oxide catalyst. It was confirmed that the meso-structure was not modified during the catalytic reaction, thus it can prevent the agglomeration of the oxide particles.

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16

Eka Putri, Gusliani, Syukri Arief, Novesar Jamarun, Feni Rahayu Gusti, and Annisa Novita Sary. "Characterization of Enhanced Antibacterial Effects of Silver Loaded Cerium Oxide Catalyst." Oriental Journal of Chemistry 34, no. 6 (November 15, 2018): 2895–901. http://dx.doi.org/10.13005/ojc/340629.

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Silver-cerium nanoparticles had been successfully synthesized using the sol-gel method by silver nitrate as a source of silver and cerium nitrate hexahydrate as a source of cerium. The synthesized silver-cerium nanoparticles had been characterized by X-ray diffraction,transmission electron microscopy, and scanning electron microscopy-energy dispersive X-ray. Based on the results of XRD and TEM analysis showed silver-cerium nanoparticles were spherical with the dominant size range of 8.9 -12.73 nm. SEM-EDX analysis showed silver nanoparticles covered by cerium nanoparticles that were known as the core-shell structure. Silver nanoparticles doped with cerium nanoparticles (CeONP) showed an increase in inhibitory with an increase a zone of inhibition after being doped with cerium nanoparticles. The disinfection effect of Ag-doped CeONP was more pronounced on Staphylococcus aureus than Escherichia coli, although the difference was not wide.

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17

Heo, Iljeong, Steven J. Schmieg, Se H. Oh, Wei Li, Charles H. F. Peden, Chang Hwan Kim, and János Szanyi. "Improved thermal stability of a copper-containing ceria-based catalyst for low temperature CO oxidation under simulated diesel exhaust conditions." Catalysis Science & Technology 8, no. 5 (2018): 1383–94. http://dx.doi.org/10.1039/c7cy02288c.

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18

Xu, Xieyang, Zhilin Xia, Laisheng Li, Qi Huang, Can He, and Jianbing Wang. "Catalytic Ozonation of Organics in Reverse Osmosis Concentrate with Catalysts Based on Activated Carbon." Molecules 24, no. 23 (November 29, 2019): 4365. http://dx.doi.org/10.3390/molecules24234365.

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Acid-washed activated carbon (AC-A), nitric acid modified activated carbon (AC-NO2), aminated activated carbon (AC-NH2) and cerium-loaded activated carbon (Ce/AC) were prepared and characterized by BET procedure, Boehm titration and SEM. Their performances were investigated for the ozonation of p-chlorobenzoic acid (p-CBA) in its solution and organic compounds in reverse osmosis concentrate (ROC). Nitration and amination had little effect on the surface area of catalyst, but increased the concentration of surface acid and basic functional group respectively. After loading Ce, the surface area of the catalyst decreased, and amount of Ce particles were agglomerated on the surface of activated carbon. All the four catalysts can improve the removal rate of the organics in water. Among the four catalysts, Ce/AC shows the highest catalytic activity. The removal rates of p-CBA, TOC and three target pollutants (e.g., tetracycline, metoprolol, atrazine) are 99.6%, 70.38%, 97.76%, 96.21% and 96.03%, respectively. Hydroxyl radical (·OH) was proved to be the core of catalytic reaction mechanism for Ce/AC, with the contribution rate to p-CBA removal of 91.4%. The surface groups and the Ce loaded on AC were the initiator for the rapid generation of ·OH. Electron transfer between electron-rich structures and cerium oxide might be a synergistic effect that can increase catalytic activity of Ce loaded on AC. Catalytic ozonation with Ce/AC is a promising ROC treatment technology due to its efficiency and possibilities for improvement.

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19

Evdokimenko, Nikolay D., Alexander L. Kustov, Konstantin O. Kim, Igor V. Mishin, Vera D. Nissenbaum, Genadiy I. Kapustin, Timur R. Aymaletdinov, and Leonid M. Kustov. "Ce–Zr materials with a high surface area as catalyst supports for hydrogenation of CO2." Functional Materials Letters 13, no. 04 (April 14, 2020): 2040004. http://dx.doi.org/10.1142/s1793604720400044.

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The most promising way of CO2 utilization is its catalytic conversion into valuable products, in particular, the direct hydrogenation of CO2 on heterogeneous catalysts to obtain such products as synthesis gas, hydrocarbons, alcohols, esters, carboxylic acids, and some other organic molecules. Heterogeneous iron-based catalysts possess a special position among the promising candidates for the synthesis of CO2-based hydrocarbons. However, individual iron oxide catalysts have a fairly low surface area, which requires their deposition on the support or modification. CeO2 is rather attractive in catalysis because of its high oxygen storage capacity. The most effective thermal stabilizer of CeO2 is ZrO2. In this work, cerium–zirconium systems with various Ce to Zr ratios were synthesized by the method of coprecipitation in the absence and presence of the hexadecyltrimethylammonium bromide template. These systems were characterized by adsorption of N2, XRD, and DTA-TG-DTG and used as supports for 5% Fe catalysts. The activity of synthesized Fe-containing catalysts was investigated in the reaction of CO2 hydrogenation. The developed surface and the presence of cerium in the supports are the possible reasons for the high activity of Fe-containing catalysts in the hydrogenation reaction of CO2.

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20

Myltykbayeva, L. K., K. Dossumov, G. E. Yergaziyeva, M. M. Telbayeva, А. Zh Zhanatova, N. А. Assanov, N. Makayeva, and Zh Shaimerden. "Catalysts for methane conversion process." BULLETIN of the L.N. Gumilyov Eurasian National University. Chemistry. Geography. Ecology Series 134, no. 1 (2021): 44–53. http://dx.doi.org/10.32523/2616-6771-2021-134-1-44-53.

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The article describes current trends in the catalytic processing of natural gas such as partial and deep, also steam oxidation of methane and methane decomposition. Kazakhstan is rich in large energy resources. Therefore, it is important to create new gas chemical technologies that will allow gas resources to produce valuable chemical products. Currently, processes based on these reactions have not been introduced into production. There are highlighted catalyst systems for each reaction that provides good performance. The oxide catalysts based on metals of variable valency are effective in all processes. In the future, it is important to increase the activity of these catalysts. The catalysts were prepared by impregnating the carrier capillary (γ-Al2O3) by incipient wetness and subsequently dried at 2000C (2 h) and calcination at 5000C for three hours. In this article, a catalyst based on nickel-zirconium (3%NiО-2%ZrО2) is active in the partial oxidation of methane to obtain synthesis gas. On this catalyst, the reaction products are H2 - 60.5 vol.%, CO - 30.5 vol.%. On a 3%NiО-7%Со2О3-0,5%Сe2O3 catalyst in the reaction of DRY conversion methane 95.6% and the yield of hydrogen and carbon monoxide is 47.0 and 45.9 vol%, respectively. 29.6% methane is converted even at low temperatures (350°C) on catalyst 3%NiО-2%СеО2/γ-Al2O3 modified with cerium oxide in the reaction of deep oxidation of methane. Iron-based catalysts for the reaction of decomposition of methane to hydrogen gas are effective. On 5 wt.% Fe/ɣ-Al2O3 catalyst at 700°C of reaction of methane conversion was 2%, with an increase in the reaction temperature to 850°C, the methane conversion reached 13%, and the hydrogen yield is increased to 5.8 vol.%.

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Borisov, Vadim A., Zaliya A. Fedorova, Victor L. Temerev, Mikhail V. Trenikhin, Dmitry A. Svintsitskiy, Ivan V. Muromtsev, Alexey B. Arbuzov, Alexey B. Shigarov, Pavel V. Snytnikov, and Dmitry A. Shlyapin. "Ceria–Zirconia-Supported Ruthenium Catalysts for Hydrogen Production by Ammonia Decomposition." Energies 16, no. 4 (February 9, 2023): 1743. http://dx.doi.org/10.3390/en16041743.

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Сommercial cerium–zirconium oxide supports (Ce0.5Zr0.5O2, Ce0.75Zr0.25O2, and Ce0.4Zr0.5Y0.05La0.05O2) were used to prepare Ru/CeZrOx catalysts. According to the XRD and IR spectroscopy data, the supports consist of ceria-based substitutional solid solutions. The specific surface areas of supports and catalysts are similar and range from 71–89 m2/g. As shown by TEM and XRD methods, the size of support particles equals 6–11 nm. According to the TEM data, the size of ruthenium particles does not exceed 1.3 nm. The catalyst activity in the ammonia decomposition process was studied. The Ru/Ce0.75Zr0.25O2 catalyst at temperature 500 °C and GHSV 120,000 h−1 demonstrated the highest hydrogen productivity of 53.3 mmol H2/(gcat·min) and compares well with the best results reported in the literature. The kinetics of ammonia decomposition reaction were calculated using the Temkin–Pyzhov exponential expression. The developed mathematical model well described the experimental data. The studied catalysts demonstrated high activity for the ammonia decomposition reaction.

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Farooq, Nosheen, Rafael Luque, Mahmoud M. Hessien, Ashfaq Mahmood Qureshi, Farzana Sahiba, Muhammad Altaf Nazir, and Aziz ur Rehman. "A Comparative Study of Cerium- and Ytterbium-Based GO/g-C3N4/Fe2O3 Composites for Electrochemical and Photocatalytic Applications." Applied Sciences 11, no. 19 (September 27, 2021): 9000. http://dx.doi.org/10.3390/app11199000.

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The design of sustainable and efficient materials for efficient energy storage and degradation of environmental pollutants (specifically organic dyes) is a matter of major interest these days. For this purpose, cerium- and ytterbium-based GO/g-C3N4/Fe2O3 composites have been synthesized to explore their properties, especially in charge storage devices such as supercapacitors, and also as photocatalysts for the degradation of carcinogenic dyes from the environment. Physicochemical studies have been carried out using XRD, FTIR, SEM, and BET techniques. Electrochemical techniques (cyclic voltammetry, galvanic charge discharge, and electrochemical impedance spectroscopy) have been employed to measure super-capacitance and EDLC properties. Results show that the gravimetric capacitance calculated from GCD results is 219 Fg−1 for ytterbium- and 169 Fg−1 for cerium-based nanocomposites at the current density of 1 A/g and scan rate of 2 mV/sec. The specific capacitance calculated for the ytterbium-based nanocomposite is 189 Fg−1 as compared to 125 Fg−1 for the cerium-based material. EIS results pointed to an enhanced resistance offered by cerium-based nanocomposites as compared to that of ytterbium, which can be assumed with the difference in particle size, as confirmed from structural studies including XRD. From obtained results, ytterbium oxide-based GO/g-C3N4/Fe2O3 is proven to be a better electro-catalyst as compared to cerium-based nanocomposites. Photocatalytic results are also in agreement with electrochemical results, as the degradation efficiency of ytterbium oxide-based GO/g-C3N4/Fe2O3 (67.11 and 83.50% for rhodamine B and methylene blue dyes) surpasses values observed for cerium-based GO/g-C3N4/Fe2O3 (63.08 and 70.61%).

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Ilieva, Lyuba, Dimitar Dimitrov, Elitsa Kolentsova, Anna Maria Venezia, Daniela Karashanova, Georgi Avdeev, Petya Petrova, Razvan State, and Tatyana Tabakova. "Gold-Based Catalysts for Complete Formaldehyde Oxidation: Insights into the Role of Support Composition." Catalysts 12, no. 7 (June 27, 2022): 705. http://dx.doi.org/10.3390/catal12070705.

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Formaldehyde (HCHO) is recognized as one of the most emitted indoor air pollutants with high detrimental effect on human health. Significant research efforts are focused on HCHO removal to meet emission regulations in an effective and economically profitable way. For over three decades, the unique electronic properties and catalytic abilities of nano-gold catalysts continue to be an attractive research area for the catalytic community. Recently, we reported that mechanochemical mixing is a relevant approach to the preparation of Co-Ce mixed oxides with high activity in complete benzene oxidation. A trend of higher surface defectiveness, in particular, oxygen vacancies, caused by close interaction between cobalt oxide and cerium oxide phases, was observed for a mixed oxide composition of 70 wt.% Co3O4 and 30 wt.% CeO2. These results directed further improvement by promotion with gold and optimization of mixed oxide composition, aiming for the development of an efficient catalyst for room temperature HCHO abatement. Support modification with potassium was studied; however, the K addition caused less enhancement of HCHO oxidation activity than expected. This motivated the preparation of new carrier material. In addition to Co3O4-CeO2 mixed metal oxides with preset ratio, γ-Al2O3 intentionally containing 33% boehmite and shortly named Al2O3-b was used for synthesis. Analysis of the role of support composition in HCHO oxidation was based on the characterization of nano-gold catalysts by textural measurements, XRD, HRTEM, XPS, and TPR techniques. Gold supported on mechanochemically treated Co3O4-CeO2-Al2O3-b (50 wt.% Al2O3-b) exhibited superior activity owing to high Ce3+ and Co3+ surface amounts and the most abundant oxygen containing species with enhanced mobility. This catalyst achieved oxidation to CO2 and H2O by 95% HCHO conversion at room temperature and 100% at 40 °C, thus implying the potential of this composition in developing efficient catalytic materials for indoor air purification.

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Balamurugan, S., and V. Sajith. "Stabilization Studies of Zirconium-Cerium Oxide Nanoparticle-Diesel Suspension." Advanced Materials Research 685 (April 2013): 128–33. http://dx.doi.org/10.4028/www.scientific.net/amr.685.128.

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One of the methods for simultaneous improvement of combustion efficiency and reduction of hydrocarbon and nitrogen oxide emissions from diesel engines is the use of catalyst in nanosized form in diesel. Agglomeration of nanoparticles in the base fluid being a serious issue, stability of the nanofluid i.e. the catalytic nanoparticles in diesel is of much concern. In the present work Zr-CeO2 nanoparticles, which acts as storage buffer leading to the reduction of the emissions, were suspended in diesel. The nanofluids were synthesized by two step method and the dosing levels of Zr-CeO2 were varied from 5 to 25 ppm. The surfactant used to improve the stability of the nanofluid was Oleic acid. The optimum concentration of surfactant in diesel fuel was determined as 0.6 percentage by volume in diesel, by the estimation of CMC value of surfactant based on surface tension measurement. The stability of synthesized nanofluids was measured using turbidity meter which shows a good stability for a dosing level of 10 ppm, with minimal settling.

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SHITANDA, Isao, Shunsuke MORI, and Masayuki ITAGAKI. "Screen-printed Dissolved Oxygen Sensor Based on Cerium Oxide-supported Silver Catalyst and Polydimethylsiloxane Film." Analytical Sciences 27, no. 10 (2011): 1049. http://dx.doi.org/10.2116/analsci.27.1049.

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26

Cossar, Emily, Alejandro Oyarce Barnett, Frode Seland, and Elena A. Baranova. "The Performance of Nickel and Nickel-Iron Catalysts Evaluated As Anodes in Anion Exchange Membrane Water Electrolysis." Catalysts 9, no. 10 (September 27, 2019): 814. http://dx.doi.org/10.3390/catal9100814.

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Anion exchange membrane water electrolysis (AEMWE) is an efficient, cost-effective solution to renewable energy storage. The process includes oxygen and hydrogen evolution reactions (OER and HER); the OER is kinetically unfavourable. Studies have shown that nickel (Ni)- iron (Fe) catalysts enhance activity towards OER, and cerium oxide (CeO2) supports have shown positive effects on catalytic performance. This study covers the preliminary evaluation of Ni, Ni90Fe10 (at%) and Ni90Fe10/CeO2 (50 wt%) nanoparticles (NPs), synthesized by chemical reduction, as OER catalysts in AEMWE using commercial membranes. Transmission electron microscopy (TEM) images of the Ni-based NPs indicate NPs roughly 4–6 nm in size. Three-electrode cell measurements indicate that Ni90Fe10 is the most active non-noble metal catalyst in 1 and 0.1 M KOH. AEMWE measurements of the anodes show cells achieving overall cell voltages between 1.85 and 1.90 V at 2 A cm−2 in 1 M KOH at 50 °C, which is comparable to the selected iridium-black reference catalyst. In 0.1 M KOH, the AEMWE cell containing Ni90Fe10 attained the lowest voltage of 1.99 V at 2 A cm−2. Electrochemical impedance spectroscopy (EIS) of the AEMWE cells using Ni90Fe10/CeO2 showed a higher ohmic resistance than all catalysts, indicating the need for support optimization.

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27

Khan, Shahid Ali, Sher Bahadar Khan, and Abdullah M. Asiri. "Electro-catalyst based on cerium doped cobalt oxide for oxygen evolution reaction in electrochemical water splitting." Journal of Materials Science: Materials in Electronics 27, no. 5 (February 6, 2016): 5294–302. http://dx.doi.org/10.1007/s10854-016-4427-3.

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28

Milanese, Marco, Andrea Manzo, Gianpiero Colangelo, and Arturo de Risi. "Development of a novel CO₂ splitting fixed-bed reactor based on copper-doped cerium oxide." Journal of Physics: Conference Series 2385, no. 1 (December 1, 2022): 012047. http://dx.doi.org/10.1088/1742-6596/2385/1/012047.

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Abstract Global warming has received widespread attention in recent years due to the accumulation of carbon dioxide. Looking at the current energy landscape, new technologies must be developed to reduce CO2 emissions. The present work is aimed to develop and test a new prototype of an innovative reactor for the conversion of CO2 into CO, operating according to a two-phase thermochemical cycle. The innovative and main aspect of this study was the use of a reactor coupled with a new type of catalyst, a copper-doped cerium oxide (Cuδ+2Ce(1-δ)O2), which allowed to decrease the temperature of the reaction up to 850°C, much lower than the models present in the literature, tested on 1300/1400°C and even beyond.

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Menegazzo, Federica, Cristina Pizzolitto, Elena Ghedini, Alessandro Di Michele, Giuseppe Cruciani, and Michela Signoretto. "Development of La Doped Ni/CeO2 for CH4/CO2 Reforming." C 4, no. 4 (November 7, 2018): 60. http://dx.doi.org/10.3390/c4040060.

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Methane dry reforming (MDR) allows the transformation of carbon dioxide and methane, the two main greenhouse gases, into syngas. Given the high endothermicity of the process, it is necessary to produce a catalytic system that is very active, selective and resistant to coking deactivation; this work focuses on the development of a heterogeneous catalyst based on nickel supported on cerium oxide. Several strategies of synthesis of the catalysts were studied with particular attention to the lanthanum addition methodology. Both supports and catalysts, fresh and used, were deeply characterized by different techniques (N2 physisorption, TPR, XRD, SEM). The effect of temperature on activity and selectivity of the different catalysts was also studied. A positive effect of lanthanum addition is strongly related to the synthetic methodology. Incipient wetness impregnation of lanthanum precursor on an already calcined ceria has led to the best catalytic activity. This behaviour is due to a more effective interaction between nickel and the support, which results in a higher dispersion of the active phase. The structural modifications have led to an improvement of the redox pump of the ceria, reducing the formation of coke during the reaction and improving the stability on time on stream.

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Zhang, Zheyu, Zongyi Han, Andrea Testino, and Lorenz Gubler. "Suppressing Hydrogen Crossover and Scavenging Radicals By Incorporation of Pt and Cerium-Zirconium Oxide for Polymer Electrolyte Water Electrolyzers." ECS Meeting Abstracts MA2022-01, no. 39 (July 7, 2022): 1760. http://dx.doi.org/10.1149/ma2022-01391760mtgabs.

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Polymer electrolyte water electrolysis (PEWE) is one of the key technologies for green hydrogen production. It has the advantages of operating at relatively high current densities and differential pressures. The hydrogen gas produced, under high cathodic pressure and with a thin membrane, tends to cross over to the anode chamber, forming explosive H2/O2 gas mixture and posing severe safety concerns for the device. Literature has shown that one effective solution is the use of Pt as the recombination catalyst. On the other hand, radical attacks to the PFSA-based membrane leads to possible thinning and pinhole formation, which deteriorates the electrochemical performance and eventually causes cell failure. To this end, ceria is often employed as a radical scavenger. In this work, we report the co-incorporation of Pt and cerium-zirconium oxide in solution-cast Nafion membranes for the dual functions of suppressing hydrogen crossover and scavenging of radicals. We show that the hydrogen in oxygen content in the anode gas stream is significantly reduced with the incorporation of Pt, and the inclusion of cerium-zirconium oxide inside the membrane is able to decrease fluoride release rate in a 100-hour constant-current water electrolysis measurement. This study provides guidance in developing proton exchange membranes with enhanced durability and safe operating range.

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Motyeian, Elham, Hamid Reza Aghabozorg, and Hossein Aghabozorg. "Synthesis and Characterization of Ce_1-xZr_xO₂ Nanopaticles." Applied Mechanics and Materials 110-116 (October 2011): 1411–16. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1411.

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A series of crystalline Ce1-xZrxO2 nanoparticles (where x = 0, 0.25, 0.5, 0.75 and 1.0) have been prepared by (i) hydrothermal (ii) polymer based metal-complex precursor solution reactions. Hydrothermal method was performed with diethanol amine as hydrolysis catalyst. The effect of reaction conditions on the size of particles and their morphology were investigated. In the polymer based method, by calcination of suitable polymer precursor solutions at a temperature range between 300 and 450 °C along with variation in the period of time, the metal oxide powders were subsequently obtained. The prepared powders have been characterized by powder X-ray diffraction (XRD), X-ray Fluorescence (XRF) .These studies reveled that zirconium is a good host for insertion into Cerium oxide in fluorite structure. The as-prepared samples were further characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average diameter of the nanoparticles were calculated from line broadening of XRD peaks and confirmed by SEM and TEM studies.

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32

Tanabe, Toshitaka, Yasutaka Nagai, Takeshi Hirabayashi, Nobuyuki Takagi, Kazuhiko Dohmae, Naoki Takahashi, Shin’ichi Matsumoto, et al. "Low temperature CO pulse adsorption for the determination of Pt particle size in a Pt/cerium-based oxide catalyst." Applied Catalysis A: General 370, no. 1-2 (November 2009): 108–13. http://dx.doi.org/10.1016/j.apcata.2009.09.030.

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33

Ning, Xing, Zhi-bo Xiong, Bin Yang, Wei Lu, and Shui-mu Wu. "The Role of Nitrate on the Sol-Gel Spread Self-Combustion Process and Its Effect on the NH3-SCR Activity of Magnetic Iron-Based Catalyst." Catalysts 10, no. 3 (March 10, 2020): 314. http://dx.doi.org/10.3390/catal10030314.

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Sol-gel spread self-combustion is the burning of the complexing agent in dried gel and the oxidant. Meanwhile, high temperature takes place during the combustion process, which is harmful to the pore structure of the catalyst. The nitrate from metal nitrate precursors as an oxidant could participate in the spread of the self-combustion process. Therefore, the influence of nitrate from metal nitrate on the spread self-combustion of an iron–cerium–tungsten citric acid gel and its catalytic performance of NOx reduction were investigated by removing nitrate via the dissolution of washing co-precipitation with citric acid and re-introducing nitric acid into the former solution. It was found that the removal of nitrate contributes to enhancing the NH3–SCR activity of the magnetic mixed oxide catalyst. The NOx reduction efficiency was close to 100% for Fe85Ce10W5–CP–CA at 250 °C while the highest was only 80% for the others. The results of thermal analysis demonstrate that the spread self-combustion process of citric acid dried gel is enhanced by re-introducing nitric acid into the citric acid dissolved solution when compared with the removal of nitrate. In addition, the removal of nitrate helps in the formation of γ-Fe2O3 crystallite in the catalyst, refining the particle size of the catalyst and increasing its pore volume. The removal of nitrate also contributes to the formation of Lewis acid sites and Brønsted acid sites on the surface of the catalyst compared with the re-introduction of nitric acid. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrates that both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms exist over Fe85Ce10W5–CP–CA at 250 °C with E–R as its main mechanism.

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34

Qadeer, Nazish, Naila Jabeen, Latif U. Khan, Manzar Sohail, Muhammad Zaheer, Muhammad Vaqas, Afia Kanwal, Fatima Sajid, Samina Qamar, and Zareen Akhter. "Hydrothermal synthesis and characterization of transition metal (Mn/Fe/Cu) co-doped cerium oxide-based nano-additives for potential use in the reduction of exhaust emission from spark ignition engines." RSC Advances 12, no. 24 (2022): 15564–74. http://dx.doi.org/10.1039/d2ra01954j.

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Illustrating the synthesis of doped and undoped CeO2 nanomaterial and its potential application as a promising catalyst for additives to minimize emissions from spark ignition (SI) engines fueled with gasoline blends.

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35

Kostuch, Aldona, Pawel J. Kulesza, Anna Wadas, Beata Dembinska, Iwona A. Rutkowska, Kinga Zdunek, Enrico Negro, Vito Di Noto, and Keti Vezzu. "Enhancement of Activity Low-Pt-Content O₂-Reduction Catalysts through Formation of Hybrid Systems with Sub-Stoichiometric Cerium Oxide Nanostructures." ECS Meeting Abstracts MA2022-01, no. 49 (July 7, 2022): 2069. http://dx.doi.org/10.1149/ma2022-01492069mtgabs.

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Platinum is a main catalyst for the electroreduction of oxygen, a reaction of primary importance to the technology of low-temperature fuel cells. Due to the high cost of platinum, there is a need to significantly lower its loadings at interfaces. However, under such condition, O2-reduction reaction (ORR) often proceeds at a less positive potential, and produces higher amounts of undesirable H2O2-intermediate. Recent studies have demonstrated that the rational design of a catalytic system is based on nanostructures of platinum, or carbon-supported platinum (Pt/C), and metal oxide (MOx). By combining the catalytic properties of both components, such hybrid Pt-MOx catalysts are capable of tuning of the activity and durability of Pt. Due to strong interactions of MOx with Pt catalytic nanoparticles leading to the improved activity and durability during ORR, certain nanostructured metal oxides are considered as co-catalysts or active components of supports. The existence of specific interactions between MOx and noble metal (Pt) nanoparticles should improve the stability and activity of the metal catalytic sites due to modification of the Pt electronic structure and diminishing of the oxo (OH) species adsorption on Pt surface, thus promoting centers for the adsorption of oxygen and the cleavage of O=O bonds. The interactions mentioned above would also facilitate dispersion of Pt, inhibit their detachment and further aggregation, and, consequently, prevent or decrease their degradation during the fuel cell operation [1]. The catalytic activity of substoichiometric ceria, CeOx (where x < 2) additive results from its unique structure, presence of oxygen vacancies, and other features resulting from the 4f-electronic configuration of cerium. While the oxygen defects are likely to serve as active oxygen adsorption sites, the mixed-valent CeIII/CeIV redox sites should permit the electron shuffling within the lattice of oxygen vacancies and enhancing the ORR activity. The formation of oxygen-defects is accompanied by the localization of electrons left behind in Ce 4f states, thus leading to the formation of CeIII species capable of elongating and reducing the O–O bond strength of the adsorbed O2 molecule; consequently, by increasing the relative ratio of CeIII-to-CeIV, the ORR electrocatalytic activity can be improved [1]. Therefore, in the present study, we consider the intentionally reduced CeOx nanostructured components through subjecting them to high-temperature pretreatment in the presence of argon gas admixed with hydrogen. It is reasonable to expect that, the increased population of CeIII sites on the surfaces of the pretreated ceria particles would stabilize the neighboring active Pt-metal centers, exhibit reductive interactions toward Pt-oxo species, and to improve durability of the catalytic materials. Thus the boundary formed between the Pt-metal and CeOx-metal oxide should facilitate inhibition of the Pt oxide formation by the CeOx layer. Furthermore, our recent studies clearly show that, in the presence of ceria, the oxidative degradation of carbon carriers is also largely decreased. Finally, cerium oxide is known to act as the oxidative scavenger for free radicals such as hydroxyl (HO•) and hydroperoxyl (HOO•), which, once generated, would otherwise lead to the formation of undesirable hydrogen peroxide. Sub-stoichiometric CeOx is capable of rapidly switching between CeIII and CeIV oxidation states, thus inducing the decomposition of both radicals and peroxides. The above observation seems to be very helpful when it comes to designing highly active and durable ORR catalysts containing low platinum loadings. [1] A.Kostuch, I.A. Rutkowska, B. Dembinska, A. Wadas, E. Negro, K. Vezzù, V. Di Noto, P.J. Kulesza, Molecules 26 (2021) 5147. Acknowledgements: This work was supported by the National Science Center (Poland) under Opus Project (2018/29/B/ST5/02627) and under auspices of the European Union EIT Raw Materials ALPE 19247 Project (Specific Grant Agreement No. EIT/RAW MATERIALS/SGA2020/1).

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Guo, Bin, Liqing Yang, Weijie Hu, Wenlong Li, and Haojing Wang. "Effect of nano-sized cerium–zirconium oxide solid solution on far-infrared emission properties of tourmaline powders." Modern Physics Letters B 29, no. 30 (November 4, 2015): 1550183. http://dx.doi.org/10.1142/s0217984915501833.

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Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline [Formula: see text], where [Formula: see text] is [Formula: see text], [Formula: see text], [Formula: see text], or vacancy; [Formula: see text] is [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], or [Formula: see text]; [Formula: see text] is [Formula: see text], [Formula: see text], [Formula: see text], or [Formula: see text]; [Formula: see text] is [Formula: see text], [Formula: see text]; and [Formula: see text] is [Formula: see text], [Formula: see text], or [Formula: see text] powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that [Formula: see text] ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher [Formula: see text] ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of [Formula: see text] and [Formula: see text] crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce–Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of [Formula: see text] to [Formula: see text] inside the tourmaline caused by the change in the catalyst redox properties of [Formula: see text] brought about by doping with [Formula: see text]. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800[Formula: see text]C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

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37

Bennett, Liam James, and Glenn Jones. "The influence of the Hubbard U parameter in simulating the catalytic behaviour of cerium oxide." Phys. Chem. Chem. Phys. 16, no. 39 (2014): 21032–38. http://dx.doi.org/10.1039/c4cp00928b.

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Анотація:

The redox properties of cerium dioxide lead to broad application in catalysis, however obtaining a consistent description from DFT is troublesome. Herein we present an approach to choose the U parameter based on adsorption energetics and apply it to construct metal-oxide parings for model catalysts.

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38

Morozova, L. V., and I. A. Drozdova. "Synthesis of dispersed mesoporous powders solid solution Zr0.88Ce0.12O2 for catalyst carrier of the conversion of methane to synthesis –gas." Perspektivnye Materialy, no. 11 (2020): 73–83. http://dx.doi.org/10.30791/1028-978x-2020-6-73-83.

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The xerogels in the system 0.88 mol.% ZrO2 − 0.12 mol.% CeO2 were obtained by the method of coprecipitation in a neutral (pH = 7) and slightly alkaline (pH = 9) medium under the influence of ultrasound with the size of the agglomerates 70 – 230 nm. It is shown that the coprecipitation of hydroxides of zirconium and cerium at pH = 9 with the use of ultrasonic treatment facilitates the formation of a primary crystal is symbolic of the particles in the xerogel, whose size is ~ 5 nm, whereas the xerogel synthesized in a neutral environment consists only of the x-ray amorphous phase. The effect of pH-precipitation on deposition processes of dehydration of the xerogels and crystallization solid solution based on zirconia oxide in the metastable pseudocubic modification (с′-ZrO2) was discovered. It was found that in the temperature range 500 – 800 °C there is a phase transition с′-ZrO2 → t-ZrO2, the size of the crystallites of the formed tetragonal solid solutions is 8 and 11 nm. The method of low-temperature nitrogen adsorption were investigated dispersion properties and characteristics of the pore structure of the powders of the solid solution Zr0.88Ce0.12O2. It is determined that the specific surface area of t-ZrO2 samples obtained after firing at 800 °C is 117 and 178 m2/g, the total pore volume reaches 0.300 − 0.325 cm3/g, the pore size distribution is monomodal and is in the range of 2 − 8 nm. The effect of thermal “aging” at a temperature of 800 °C (40 h) on the structure and dispersion of the solid solution t-ZrO2 powders was studied.

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39

Sandra, F. P. R., U. B. Demirci, P. Miele, and S. Bernard. "Screening and scale-up of cerium oxide-based binary/ternary systems as oxidation catalysts." RSC Advances 6, no. 33 (2016): 27426–33. http://dx.doi.org/10.1039/c6ra03179j.

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40

SUMIDA, Hirosuke, Yuki KODA, Kenji OKAMOTO, Masaru TAKATOO, Masahiko SHIGETSU, and Kazunari KOMATSU. "Sulfur Poisoning of Palladium-based Catalysts Using Cerium Oxide." NIPPON KAGAKU KAISHI, no. 10 (1998): 697–703. http://dx.doi.org/10.1246/nikkashi.1998.697.

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41

Tschope, A., W. Liu, M. Flytzanistephanopoulos, and J. Y. Ying. "Redox Activity of Nonstoichiometric Cerium Oxide-Based Nanocrystalline Catalysts." Journal of Catalysis 157, no. 1 (November 1995): 42–50. http://dx.doi.org/10.1006/jcat.1995.1266.

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42

Fleming, Charlotte L., Jessie Wong, Mojtaba Golzan, Cindy Gunawan, and Kristine C. McGrath. "Insights from a Bibliometrics-Based Analysis of Publishing and Research Trends on Cerium Oxide from 1990 to 2020." International Journal of Molecular Sciences 24, no. 3 (January 20, 2023): 2048. http://dx.doi.org/10.3390/ijms24032048.

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Анотація:

The purpose of this study is to evaluate the literature for research trends on cerium oxide from 1990 to 2020 and identify gaps in knowledge in the emerging application(s) of CeONP. Bibliometric methods were used to identify themes in database searches from PubMed, Scopus and Web of Science Core Collection using SWIFT-Review, VOSviewer and SciMAT software programs. A systematic review was completed on published cerium oxide literature extracted from the Scopus database (n = 17,115), identifying themes relevant to its industrial, environmental and biomedical applications. A total of 172 publications were included in the systematic analysis and categorized into four time periods with research themes identified; “doping additives” (n = 5, 1990–1997), “catalysts” (n = 32, 1998–2005), “reactive oxygen species” (n = 66, 2006–2013) and “pathology” (n = 69, 2014–2020). China and the USA showed the highest number of citations and publications for cerium oxide research from 1990 to 2020. Longitudinal analysis showed CeONP has been extensively used for various applications due to its catalytic properties. In conclusion, this study showed the trend in research in CeONP over the past three decades with advancements in nanoparticle engineering like doping, and more recently surface modification or functionalization to further enhanced its antioxidant abilities. As a result of recent nanoparticle engineering developments, research into CeONP biological effects have highlighted its therapeutic potential for a range of human pathologies such as Alzheimer’s disease. Whilst research over the past three decades show the versatility of cerium oxide in industrial and environmental applications, there are still research opportunities to investigate the potential beneficial effects of CeONP in its application(s) on human health.

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ZAITZ, MAŁGORZATA M., MARCIN MOLENDA, LUCJAN CHMIELARZ, ZOFIA PIWOWARSKA, BARBARA DUDEK, STANISŁAW WALAS, and ROMAN DZIEMBAJ. "INFLUENCE OF DEFECT STRUCTURE ON CATALYTIC ACTIVITY OF NANOMETRIC MATERIALS BASED ON CERIA-DOPED COPPER." Functional Materials Letters 04, no. 02 (June 2011): 165–69. http://dx.doi.org/10.1142/s1793604711001762.

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Анотація:

A series of nanometric materials based on copper-doped cerium (IV) oxide was synthesized using a reverse (w/o) microemulsion method. The obtained powder precursors were tested by the thermal analysis methods coupled with evolved gas analysis (EGA-TGA/DTG/SDTA). Morphology and structure of the samples were characterized by XRD and BET analysis. The content of copper ions was determined using a ICP-OES spectrometer. The electronic structure of the catalysts was characterized by high-temperature electrical conductivity measurements at different pO 2. The obtained materials were tested in catalytic incineration of the selected VOCs (methanol and ethylene). The correlation between the activity of the catalysts and copper content as well as electrical properties has been confirmed.

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An, Xingshuang, Xiaojie Shi, Hui Zhang, Yao Yao, Guangxian Wang, Qingqing Yang, Lianming Xia, and Xia Sun. "An electrochemical immunosensor based on a combined amplification strategy with the GO–CS/CeO2–CS nanocomposite for the detection of aflatoxin M1." New Journal of Chemistry 44, no. 4 (2020): 1362–70. http://dx.doi.org/10.1039/c9nj04804a.

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Herein, a sensitive electrochemical immunosensor modified with graphene oxide–chitosan (GO–CS) and cerium oxide–chitosan (CeO₂–CS) using screen-printed electrodes (SPEs) was developed for the determination of aflatoxin M₁ (AFM₁) in milk.

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45

Ying, Jackie Y., and Andreas Tschöpe. "Synthesis and characteristics of non-stoichiometric nanocrystalline cerium oxide-based catalysts." Chemical Engineering Journal and the Biochemical Engineering Journal 64, no. 2 (November 1996): 225–37. http://dx.doi.org/10.1016/s0923-0467(96)03142-9.

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46

Randery, S. "Cerium oxide-based catalysts for production of ketones by acid condensation." Applied Catalysis A: General 226, no. 1-2 (March 28, 2002): 265–80. http://dx.doi.org/10.1016/s0926-860x(01)00912-7.

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47

Heponiemi, Anne, Said Azalim, Tao Hu, and Ulla Lassi. "Cerium Oxide Based Catalysts for Wet Air Oxidation of Bisphenol A." Topics in Catalysis 58, no. 14-17 (August 11, 2015): 1043–52. http://dx.doi.org/10.1007/s11244-015-0457-y.

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48

Arkhipenko, A. A., E. S. Koshel, and V. B. Baranovskaya. "Analysis of cerium oxide by arc atomic emission spectrometry." Industrial laboratory. Diagnostics of materials 87, no. 11 (November 21, 2021): 19–25. http://dx.doi.org/10.26896/1028-6861-2021-87-11-19-25.

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Анотація:

Materials based on rare earth elements (REE) are of great importance due to their unique chemical and physical properties, but the effectiveness of their use depends on the quality of raw materials. Therefore, further development of the methods of analytical control in relation to rare-earth materials is aimed at increasing the accuracy and sensitivity of the methods, as well as at expanding the nomenclature and concentration range of the determined elements. Cerium oxide is used in glasses, ceramics, catalysts, phosphors, composite and scintillation materials, as well as in medicine. The problem of developing a new arc spectral method is extremely urgent to match modern requirements for the accuracy and sensitivity of the impurity determination for monitoring the purity of cerium oxide. A technique for arc atomic emission analysis of cerium oxide which meets modern requirements for the accuracy and sensitivity of the impurity determination has been developed. The range of impurities to be determined is significantly expanded compared to the standardized technique of the 1970s. The goal of this work is to study and develop a modern method for arc optical emission spectral analysis of cerium oxide using the instrumental capabilities of the atomic emission complex «Grand Globula». To specify compromise conditions for the determination of 15 REE impurities and 19 elements more, analytical lines were selected and the dependence of their intensity on the operating mode of the generator, the shape and size of the electrodes, the interelectrode distance, the ratio of the masses of the analyzed sample and graphite powder, as well as on the presence of various carriers (Ga2O3, NaCl, NaF, KCl, S, GeO) was analyzed. Application of the considered methodological approach to the selection of conditions made it possible to develop a method for spectral analysis of cerium oxide without preliminary dissolution of the sample with an extended range of determinable impurities. When studying the curves of the impurity evaporation, an exposure time was chosen to be sufficient for their complete evaporation (100 – 120 sec). The study has shown the 0promising character and feasibility of the developed arc spectral techniques applicable to the analysis of REE-based materials as an alternative to the methods for analysis of solutions. The metrological characteristics of the proposed procedure for the analysis of cerium oxide were evaluated in comparison with the standardized technique.

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49

Annis, James W., Janet M. Fisher, David Thompsett, and Richard I. Walton. "Solvothermal Synthesis Routes to Substituted Cerium Dioxide Materials." Inorganics 9, no. 6 (May 21, 2021): 40. http://dx.doi.org/10.3390/inorganics9060040.

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We review the solution-based synthesis routes to cerium oxide materials where one or more elements are included in place of a proportion of the cerium, i.e., substitution of cerium is performed. The focus is on the solvothermal method, where reagents are heated above the boiling point of the solvent to induce crystallisation directly from the solution. This yields unusual compositions with crystal morphology often on the nanoscale. Chemical elements from all parts of the periodic table are considered, from transition metals to main group elements and the rare earths, including isovalent and aliovalent cations, and surveyed using the literature published in the past ten years. We illustrate the versatility of this synthesis method to allow the formation of functional materials with applications in contemporary applications such as heterogeneous catalysis, electrodes for solid oxide fuel cells, photocatalysis, luminescence and biomedicine. We pick out emerging trends towards control of crystal habit by use of non-aqueous solvents and solution additives and identify challenges still remaining, including in detailed structural characterisation, the understanding of crystallisation mechanisms and the scale-up of synthesis.

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50

Varvoutis, Georgios, Maria Lykaki, George E. Marnellos, and Michalis Konsolakis. "Recent Advances on Fine-Tuning Engineering Strategies of CeO2-Based Nanostructured Catalysts Exemplified by CO2 Hydrogenation Processes." Catalysts 13, no. 2 (January 26, 2023): 275. http://dx.doi.org/10.3390/catal13020275.

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Ceria-based oxides have been extensively involved in a wide range of catalytic applications due to their intriguing properties, related mostly to their superior redox features in conjunction with peculiar metal-support interaction phenomena. Most importantly, the fine-tuning of key interrelated factors, such as the size, morphology and electronic state of the catalyst’s counterparts, can exert a profound influence on the intrinsic characteristics and interfacial reactivity with pronounced implications in catalysis. The present review, while also elaborating our recent efforts in the field, aims to provide key fundamental and practical aspects in relation to the rational design and functionalization strategies of ceria-based catalysts, exemplified by the CO2 hydrogenation processes, namely, CO2 methanation and reverse water–gas shift (rWGS) reactions. Firstly, a description of the most prominent catalytically relevant features of cerium oxide is provided, focusing on reducibility and metal-support interaction phenomena, followed by a brief overview of the current status of ceria-based catalysts for various energy and environmental applications. Then, the main implications of fine-tuning engineering via either appropriate synthesis routes or aliovalent doping on key activity descriptors are thoroughly discussed and exemplified by state-of-the-art ceria-based catalysts for CO2 hydrogenation. It is clearly revealed that highly active and cost-efficient ceria-based catalytic materials can be obtained on the grounds of the proposed functionalization strategy, with comparable or even superior reactivity to that of noble metal catalysts for both the studied reactions. In a nutshell, it can be postulated that the dedicated fabrication of CeO2-based systems with augmented redox capabilities and, thus, oxygen vacancies abundance can greatly enhance the activation of gas-phase CO2 towards CO or CH4. Besides, the morphology-engineering of CeO2-based catalysts can notably affect the CO2 hydrogenation performance, by means of an optimum metal-ceria interphase based on the exposed facets, whereas doping and promotion strategies can effectively shift the reaction pathway towards the selective production of either CO or CH4. The conclusions derived from the present work can provide design and fine-tuning principles for cost-efficient, highly active and earth-abundant metal oxide systems, not only for the CO2 hydrogenation process but for various other energy and environmental applications.

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