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Preparation, Characterization of CuO/CeO_2 and Cu/CeO_2 Catalysts and Their Applications in Low-Temperature CO Oxidation 被引量:7
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作者 郑修成 韩东战 +4 位作者 王淑萍 张守民 王淑荣 黄唯平 吴世华 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第1期47-51,共5页
CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were ... CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/ CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts. 展开更多
关键词 catalytic chemistry cuo/ceo2 catalysts Cu/ceo2 catalysts carbon monoxide oxidation rare earths
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Effect of Addition of Base on Ceria and Reactivity of CuO/CeO_2 Catalysts for Low-Temperature CO Oxidation 被引量:1
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作者 Xiucheng Zheng Xiaoli Zhang +2 位作者 Shuping Wang Xiangyu Wang Shihua Wu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2007年第2期179-185,共7页
In this work, we have reported the influence of the addition of base (KOH) on the physicochemical property of ceria synthesized by alcohothermal process, and the alcohothermal mechanism was also put forward. Further... In this work, we have reported the influence of the addition of base (KOH) on the physicochemical property of ceria synthesized by alcohothermal process, and the alcohothermal mechanism was also put forward. Furthermore, the prepared CeO2 was used as the support to prepare CuO/CeO2 catalysts via the wet impregnation method. The samples were characterized by N2 adsorption-desorption, X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and temperatureprogrammed reduction by H2 (H2-TPR). The catalytic properties of the CuO/CeO2 catalysts for lowtemperature CO oxidation were studied using a microreactor-GC system. The crystal size of CeO2-A was much smaller than that of CeO2-B, and the corresponding copper oxide catalysts exhibited higher catalytic activity than that of the CeO2-B-supported catalysts under the same reaction conditions. The alcohothermal mechanism indicated that KOH plays a key role in determining the physicochemical and catalytic properties of ceria-based materials. 展开更多
关键词 alcohothermal synthesis CERIA cuo/ceo2 catalyst CO oxidation alcohothermal mechanism
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Catalytic Oxidative Properties and Characterization of CuO/CeO_2 Catalysts 被引量:1
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作者 蒋晓原 周仁贤 +2 位作者 袁骏 吕光烈 郑小明 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第1期55-59,共5页
The oxidative properties and characterization of CuO, CeO 2 and CuO/CeO 2 cata lysts were examined by means of a CO micro-reactor GC system, TPR, XPS and X-r ay diffraction Rietveld methods. The results show that ei... The oxidative properties and characterization of CuO, CeO 2 and CuO/CeO 2 cata lysts were examined by means of a CO micro-reactor GC system, TPR, XPS and X-r ay diffraction Rietveld methods. The results show that either CuO or CeO 2 ac tivity is quite low for CO oxidation. However, when CuO and CeO 2 are mixed, the oxidative activity of the catalyst increases significantly, probably owing to the valency status of copper species (Cu 2+ and Cu+) on the CeO 2 surfa ce, the dispersion and reducibility. XPS surface analysis shows that CuO loading is very important in forming of either Cu 2+ or Cu+. Rietveld analysis s hows that some CuO, which has smaller ion radius than Ce 4+, enters the Ce O 2 lattice after CuO and CeO 2 are mixed. When the CuO loading reaches 5.0%, the size of CuO crystals is a minimum (6.1 nm) and the micro-strain value i s a maximum (2.86×10 -3), resulting in high surface energy and the best ac tivity for CO oxidation. 展开更多
关键词 physical chemistry cuo/ceo 2 catalysts CO micro-reactor GC system rare earths
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Effect of Cesium Modification on CuO/CeO2 Catalysts for the Catalytic Decomposition of N2O 被引量:2
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作者 GUO Peiwen QIN Feng +3 位作者 SUN Chao HUANG Zhen SHEN Wei XU Hualong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2019年第1期47-52,共6页
A series of Cs-modified CuO/CeO2 mixed oxide catalysts was prepared for enhancing the stable activity of N2O decomposition.It was found that Cs modification promoted the catalytic performance of CuO/CeO2 catalysts sig... A series of Cs-modified CuO/CeO2 mixed oxide catalysts was prepared for enhancing the stable activity of N2O decomposition.It was found that Cs modification promoted the catalytic performance of CuO/CeO2 catalysts significantly,The l%Cs-CuO/CeO2 catalyst exhibited the best activity,and the conversion of N2O reached 100%at 380℃ in the presence of 2% O2.The catalytic behaviors were investigated by means of XRD,N2 adsorption isotherms,XPS,H2-TPR(TPR:temperature-prograrmmed reduction),CO-IR,O2-TPD(TPD:temperature-programmed desorption)and diffused reflectance infrared Fourier transform spectorscopy(DRiFTs).The results revealed that Cs modification promoted the activity and the oxygen resistance by enhancing the desorption of surface oxygen species and increasing the content of Ce^3+.CO-DRIFTs revealed that Ce^3+could efficiently facilitate the regeneration of active Cu^+sites by an oxygen migration step.The possible reaction mechanism was also discussed. 展开更多
关键词 Cs-Modified cuo/ceo2 N2O DECOMPOSITION REACTION mechanism
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Effect of yttrium addition on water-gas shift reaction over CuO/CeO_2 catalysts
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作者 佘育生 李雷 +3 位作者 詹瑛瑛 林性贻 郑起 魏可镁 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第3期412-418,共7页
This paper presented a study on the role of yttrium addition to CuO/CeO2 catalyst for water-gas shift reaction. A single-step co-precipitation method was used for preparation of a series of yttrium doped CuO/CeO2 cata... This paper presented a study on the role of yttrium addition to CuO/CeO2 catalyst for water-gas shift reaction. A single-step co-precipitation method was used for preparation of a series of yttrium doped CuO/CeO2 catalysts with yttrium content in the range of 0-5wt.%. Properties of the obtained samples were characterized and analyzed by X-ray diffraction (XRD), Raman spectroscopy, H2-TPR, cyclic voltammetry (CV) and the BET method. The results revealed that catalytic activity was increased with the yttrium content at first, but then decreased with the further increase of yttrium content. Herein, CuO/CeO2 catalyst doped with 2wt.% of yttrium showed the highest catalytic activity (CO conversion reaches 93.4% at 250 ℃) and thermal stability for WGS reaction. The catalytic activity was correlated with the surface area, the area of peak γ of H2-TPR profile (i.e., the reduction of surface copper oxide (crystalline forms) interacted with surface oxygen vacancies on ceria), and the area of peak C2 and A1 (Cu^0→←Cu^2+ in cyclic voltammetry process), respectively. Besides, Raman spectra provided evidences for a synergistic Cu-Ovacancy interaction, and it was indicated that doping yttrium may facilitate the formation of oxygen vacancies on ceria. 展开更多
关键词 cuo/ceo2 catalyst water-gas shift YTTRIUM cyclic voltammetry rare earths
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Effect of CeO_(2)on Activity of Catalysts CuO/ZnO/Al_(2)O_(3)/CeO_(2)for Synthesis of Methanol
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作者 Zhou Songhua Li Wenbo +7 位作者 Wu Zongjin Chen Zhongyang Huang Chen Zhang Chuanwei Wang Bo Pan Hongyan Lin Qian 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2023年第3期104-114,共11页
The size of the nanoparticles and the number of oxygen vacancies have a significant effect on the catalytic activity of copper-based catalysts used for the synthesis of methanol from syngas.In this study,the authors p... The size of the nanoparticles and the number of oxygen vacancies have a significant effect on the catalytic activity of copper-based catalysts used for the synthesis of methanol from syngas.In this study,the authors prepared a series of catalysts CuO/ZnO/Al_(2)O_(3)/CeO_(2)(CZAC)with CuO particles of different sizes and varying number of oxygen vacancies on the surface by changing the added volume of CeO2 by using the co-precipitation method.The properties of the catalysts were characterized and their activity was evaluated by using high-pressure fixed-bed reaction equipment.The results showed that the addition of CeO_(2)to CuO/ZnO/Al_(2)O_(3)not only influenced the size of the CuO particles and metal-metal interactions,but also had an effect on the concentrations of oxygen vacancies and strongly basic sites.The presence of CuO particles of small sizes and a large numbers of oxygen vacancies on the surface of the catalyst were beneficial to its activity for the synthesis of methanol.The catalyst CZAC,when modified by 5%of CeO_(2),recorded CuO particles of the smallest size(8.9 nm),strong intermetallic interactions,and the highest concentrations of oxygen vacancies and strongly basic sites.It also exhibited the highest catalytic activity,with a space-time yield of methanol of 0.315 g/(h·g)that was higher than that of the enterprise RK-5 catalyst[0.215 g/(h·g)]. 展开更多
关键词 catalyst amount of ceo_(2)added size of cuo particles oxygen vacancies methanol synthesis
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Effects of CuO-CeO<sub>2</sub>Addition on Structure and Catalytic Properties of Three Way Catalysts
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作者 Nguyen The Luong Nguyen Duy Tien +2 位作者 Eiji Yamasue Hideyuki Okumura Keiichi N. Ishihara 《Journal of Materials Science and Chemical Engineering》 2017年第12期28-39,共12页
The noble metals (Pt, Pd, Rh) supported on Cu-Ce mixed oxides with γ-Al2O3 washcoat/FeCrAl substrate were investigated as catalytic performance of Three Way Catalysts (TWC) under simulated automotive exhaust feed gas... The noble metals (Pt, Pd, Rh) supported on Cu-Ce mixed oxides with γ-Al2O3 washcoat/FeCrAl substrate were investigated as catalytic performance of Three Way Catalysts (TWC) under simulated automotive exhaust feed gas. The structural, morphological features and catalytic activity were observed by X-ray diffractometry (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) and GC-TCD (Varian CP-4900). The catalytic performance of noble metals (Pt, Rh, Pd) supported on Cu-Ce mixed oxides with γ-Al2O3 washcoat/FeCrAl substrate was be compared with noble metals (Pt, Rh, Pd) supported on Ce-Zr mixed oxides with γ-Al2O3 washcoat/FeCrAl substrate and only γ-Al2O3 washcoat/FeCrAl substrate at various stoichiometric ratio of oxygen. The results showed that the addition of Cu-Ce mixed oxides improved CO oxidation reaction at lower temperature during stable lambda of 1, the highest CO conversion of 99% is observed for the noble metals (Pt, Pd, Rh) support on Cu-Ce with γ-Al2O3 washcoat/FeCrAl substrate. The results also showed that, the addition of Cu-Ce mixed oxides promoted released oxygen, thus it improved strongly CO and C3H8 conversion at lean oxygen stoichiometric operation. 展开更多
关键词 Three-Way catalysts (TWCs) NOBLE Metals γ-Al2O3 WASHCOAT cuo-ceo2 ceo2-ZRO2
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Introduction of ZnO,Sn,and P promoters in CuO/CeO_(2) catalysts for improved production of dimethyldichlorosilane in the Rochow-Müller reaction
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作者 Xinyang Li Yongxia Zhu +5 位作者 Baofang Jin Yongjun Ji Lei Shi Dongxing Fu Dingrong Bai Fabing Su 《Resources Chemicals and Materials》 2022年第3期249-260,共12页
Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling meth... Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling method and CeO_(2) support, we prepared a high-performance CuO-ZnO-P-Sn/CeO_(2) catalyst by integrating highly dispersed multicomponent promoters of ZnO, Sn, and P with the active component CuO. This catalyst shows a significantly enhanced dimethyldichlorosilane selectivity because these promoters can substantially increase the Cu+ content and the formation of an active CuxSi phase. This work provides a new approach to efficiently designing Cu-based catalysts for the Rochow-Müller reaction. 展开更多
关键词 Rochow-Miller reaction cuo/ceo_(2)catalyst Promoters Heterogene0us catalysis Solid-phase synthesis
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CuO/CeO_(2)/γ-Al_(2)O_(3)工业球型催化剂的制备及其脱除石灰窑尾气CO的性能
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作者 宓家宁 杨瑞瑶 +3 位作者 赵文 王保举 张立平 于如军 《石油化工》 CAS CSCD 北大核心 2024年第10期1466-1472,共7页
采用分步浸渍法制备了CuO/CeO_(2)/γ-Al_(2)O_(3)工业球型催化剂。通过XRD,SEM,TEM,Raman,H_(2)-TPR等方法对催化剂的结构进行表征,并将CuO/CeO_(2)/γ-Al_(2)O_(3)应用于石灰窑尾气处理中,考察了CuO/CeO_(2)/γ-Al_(2)O_(3)的CO催化... 采用分步浸渍法制备了CuO/CeO_(2)/γ-Al_(2)O_(3)工业球型催化剂。通过XRD,SEM,TEM,Raman,H_(2)-TPR等方法对催化剂的结构进行表征,并将CuO/CeO_(2)/γ-Al_(2)O_(3)应用于石灰窑尾气处理中,考察了CuO/CeO_(2)/γ-Al_(2)O_(3)的CO催化氧化效果及使用寿命。实验结果表明,在气体流量为1 m^(3)/h,150℃条件下,CuO/CeO_(2)/γ-Al_(2)O_(3)脱除石灰窑尾气(2%(φ)CO,2%(φ)O_(2),35%(φ)CO_(2)及N2)时,可实现超350 h的稳定运行,且稳定运行后催化剂的结构并未被破坏。 展开更多
关键词 cuo/ceo_(2)/γ-Al_(2)O_(3) 球型催化剂 CO氧化 石灰窑尾气
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Influence of preparation methods on the physicochemical properties and catalytic performance of MnO_x-CeO_2 catalysts for NH_3-SCR at low temperature 被引量:47
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作者 Xiaojiang Yao Kaili Ma +4 位作者 Weixin Zou Shenggui He Jibin An Fumo Yang Lin Dong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第1期146-159,共14页
This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature.... This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation,hydrothermal treatment, co‐precipitation, and a sol‐gel technique, were used to synthesizeMnOx‐CeO2 catalysts. The catalysts were characterized in detail, and an NH3‐SCR model reaction waschosen to evaluate the catalytic performance. The results showed that the preparation methodsaffected the catalytic performance in the order: hydrothermal treatment > sol‐gel > co‐precipitation> impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content,oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sitesand acidic strength. This trend is related to redox interactions between MnOx and CeO2. The catalystformed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalyticperformance, and good H2O resistance in NH3‐SCR reaction. This was attributed to incorporationof Mnn+ into the CeO2 lattice to form a uniform ceria‐based solid solution (containing Mn‐O‐Cestructures). Strengthening of the electronic interactions between MnOx and CeO2, driven by thehigh‐temperature and high‐pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment‐friendly route to synthesizing low‐temperature denitrification (deNOx) catalysts. 展开更多
关键词 MnOx‐ceo2 catalyst Preparation method Nitrogen oxides Low‐temperature NH3‐SCR Electron interaction Surface acidity
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Characterization of CuO Species and Thermal Solid-Solid Interaction in CuO/CeO_2-Al_2O_3 Catalyst by In-Situ XRD, Raman Spectroscopy and TPR 被引量:9
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作者 何迈 罗孟飞 方萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第2期188-192,共5页
Transference of CuO species and thermal solid-solid interaction in CuO/CeO2-Al2O3 catalyst prepared by an impregnation method were characterized by in-situ XRD, Raman spectroscopy and H2-TPR techniques. For the cataly... Transference of CuO species and thermal solid-solid interaction in CuO/CeO2-Al2O3 catalyst prepared by an impregnation method were characterized by in-situ XRD, Raman spectroscopy and H2-TPR techniques. For the catalyst calcined at 300℃, two kinds of CuO species coexist on the surface, that is, highly dispersed and bulk CuO crystalline phase. Four kinds of CuO species are present for the catalyst calcined at 600 ℃, : (1) highly dispersed CuO, (2) bulk CuO on the surface, (3) bulk CuO in the internal layer of CeO2, and (4) CuAl2O4 formed from CuO-Al2O3 interaction. For the catalyst calcined at 800 ℃,C, besides very little highly dispersed and bulk CuO on the surface, most of the CuO has transferred into the internal layer of CeO2 and the mass of CuAl2O4 are increased. At 900 ℃,, all of CuO has diffused into the internal layer of CeO2 and formed CuAl2O4. The results show that the distribution of CuO species in the catalysts depends on the calcination temperature; the different CuO species can be effectively confirmed by in-situ XRD, Raman spectroscopy and H2-TPR techniques. 展开更多
关键词 cuo/ceo2-Al2O3 TPR solid-solid interaction rare earths
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A comparative study of CuO/TiO_2-SnO_2,CuO/TiO_2 and CuO/SnO_2 catalysts for low-temperature CO oxidation 被引量:8
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作者 Kairong Li Yaojie Wang Shurong Wang Baolin Zhu Shoumin Zhang Weiping Huang Shihua Wu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2009年第4期449-452,共4页
Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA... Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA, XRD, H2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO, and the optimum CuO loading was 8 wt.% (Tloo = 80 ℃). The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO2 and CuO/SnO2 catalysts. H2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst. 展开更多
关键词 sol-gel dialytic processes cuo/TiO2-SnO2 catalyst low-temperature CO oxidation
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Identification of relevant active sites and a mechanism study for reverse water gas shift reaction over Pt/CeO_2 catalysts 被引量:6
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作者 Xiaodong Chen Xiong Su +5 位作者 Binglian Liang Xiaoli Yang Xinyi Ren Hongmin Duan Yanqiang Huang Tao Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期1051-1057,共7页
Reverse water gas shift (RWGS) reaction can serve as a pivotal stage in the CO2 conversion processes, which is vital for the utilization of CO2. In this study, RWGS reaction was performed over Pt/CeO2 catalysts at the... Reverse water gas shift (RWGS) reaction can serve as a pivotal stage in the CO2 conversion processes, which is vital for the utilization of CO2. In this study, RWGS reaction was performed over Pt/CeO2 catalysts at the temperature range of 200-500 degrees C under ambient pressure. Compared with pure CeO2, Pt/CeO2 catalysts exhibited superior RWGS activity at lower reaction temperature. Meanwhile, the calculated TOF and E-a values are approximately the same over these Pt/CeO2 catalysts pretreated under various calcination conditions, indicating that the RWGS reaction is not affected by the morphologies of anchored Pt nanoparticles or the primary crystallinity of CeO2. TPR and XPS results indicated that the incorporation of Pt promoted the reducibility of CeO2 support and remarkably increased the content of Ce 3 + sites on the catalyst surface. Furthermore, the CO TPSR-MS signal under the condition of pure CO2 flow over Pt/CeO 2 catalyst is far lower than that under the condition of adsorbed CO2 with H-2 -assisted flow, revealing that CO2 molecules adsorbed on Ce3+ active sites have difficult in generating CO directly. Meanwhile, the adsorbed CO2 with the assistance of H-2 can form formate species easily over Ce3+ active sites and then decompose into Ce3+-CO species for CO production, which was identified by in-situ FTIR. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved. 展开更多
关键词 RWGS reaction Pt/ceo2 catalyst Formate intermediate MECHANISM
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Preferential oxidation of CO in excess H_2 over the CeO_2/CuO catalyst: Effect of initial support 被引量:2
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作者 Zhiming Gao Yuanyuan Gong +2 位作者 Qiang Zhang Hao Deng Yong Yue 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第4期475-482,共8页
Three series of CeO2/CuO samples were prepared by impregnation method and characterized by XRD, N2 adsorption-desorption, temperatureprogrammed reduction (TPR), XPS and TEM techniques. In comparison with the samples... Three series of CeO2/CuO samples were prepared by impregnation method and characterized by XRD, N2 adsorption-desorption, temperatureprogrammed reduction (TPR), XPS and TEM techniques. In comparison with the samples prepared with CuO as initial support, the samples with Cu(OH)2 as initial support have higher reducibilities and smaller relative TPR peak areas, and also larger specific surface areas at calcina- tion temperatures of 400 ℃--600 ℃. As a result, Cu(OH)2 is better than CuO as initial support for preferential oxidation of CO in excess H2 (CO-PROX). The best catalytic performance was achieved on the sample calcined at 600 ℃ and with an atomic ratio of Ce/Cu at 40%. XPS analyses indicate that more interface linkages Ce-O-Cu could be formed when it was calcined at 600 ℃. And the atomic ratio of Ce/Cu at 40% led to a proper reducibility for the sample as illustrated by the TPR measurements. 展开更多
关键词 preterential oxiclation CO excess H2 ceo2/cuo catalyst TPR XPS interlace
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Screening of MgO- and CeO_2-Based Catalysts for Carbon Dioxide Oxidative Coupling of Methane to C_(2+) Hydrocarbons 被引量:5
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作者 Istadi Nor Aishah Saidina Amin 《Journal of Natural Gas Chemistry》 CAS CSCD 2004年第1期23-35,共13页
The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based so... The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively. 展开更多
关键词 catalyst screening carbon dioxide oxidative coupling METHANE ternary metal oxide binary metal oxide MGO ceo2 C2+ hydrocarbons
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CeO_2-Co_3O_4 Catalysts for CO Oxidation 被引量:3
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作者 许秀艳 李进军 郝郑平 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第2期172-176,共5页
CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction (... CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction (TPR), and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated. The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4. The catalyst with the Ce/Co atomic ratio 1 : 16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃. 展开更多
关键词 CO oxidation ceo2 CO3O4 ceo2-Co3O4 catalyst rare earths
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Electronic and geometric structure of the copper-ceria interface on Cu/CeO2 catalysts 被引量:4
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作者 Yan Zhou Aling Chen +1 位作者 Jing Ning Wenjie Shen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第6期928-937,共10页
The atomic structure of the active sites in Cu/CeO2 catalysts is intimately associated with the copper-ceria interaction. Both the shape of ceria and the loading of copper affect the chemical bonding of copper species... The atomic structure of the active sites in Cu/CeO2 catalysts is intimately associated with the copper-ceria interaction. Both the shape of ceria and the loading of copper affect the chemical bonding of copper species on ceria surfaces and the electronic and geometric character of the relevant interfaces. Nanostructured ceria, including particles(polyhedra), rods, and cubes, provides anchoring sites for the copper species. The atomic arrangements and chemical properties of the(111),(110) and(100) facets, preferentially exposed depending on the shape of ceria, govern the copper-ceria interactions and in turn determine their catalytic properties. Also, the metal loading significantly influences the dispersion of copper species on ceria with a specific shape, forming copper layers, clusters, and nanoparticles. Lower copper contents result in copper monolayers and/or bilayers while higher copper loadings lead to multi-layered clusters and faceted particles. The active sites are usually generated via interactions between the copper atoms in the metal species and the oxygen vacancies on ceria, which is closely linked to the number and density of surface oxygen vacancies dominated by the shape of ceria. 展开更多
关键词 Cu/ceo2 catalyst Ceria shape Oxygen vacancy Copper particle Copper-ceria interface Active site
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Methane reforming with CO_2 to syngas over CeO_2-promoted Ni/Al_2O_3-ZrO_2 catalysts prepared via a direct sol-gel process 被引量:2
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作者 Hansheng Li Hang Xu Jinfu Wang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第1期1-8,共8页
CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared s... CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy (IR), thermal gravimetric analysis (TGA), microscopic analysis, X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports. 展开更多
关键词 methane reforming with CO2 SYNGAS Ni-based catalyst ceo2 sol-gel process
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Stable CuO/La_(2)Sn_(2)O_(7) catalysts for soot combustion:Study on the monolayer dispersion behavior of CuO over a La_(2)Sn_(2)O_(7) pyrochlore support 被引量:2
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作者 Xiaohui Feng Rui Liu +6 位作者 Xianglan Xu Yunyan Tong Shijing Zhang Jiacheng He Junwei Xu Xiuzhong Fang Xiang Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第3期396-408,共13页
To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO lo... To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations.In these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)surface.When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure.In contrast,Cu has negligible interactions with La at the A-sites.This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support.The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion activity.The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached.Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites.In summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer. 展开更多
关键词 cuo/La_(2)Sn_(2)O_(7)catalyst Soot combustion DFT calculations Preferential interaction Monolayer dispersion on pyrochlore support Active O2^(-)and O2^(2-)sites
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Effects of ZrO_2 Content on Structure and Performance of Cu/CeO_2-ZrO_2 Catalysts for Water-Gas Shift Reaction 被引量:1
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作者 郑云弟 林性贻 +3 位作者 郑起 詹瑛瑛 李达林 魏可镁 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第6期685-689,共5页
Cu/CeO2-ZrO2 catalysts for water-gas shift (WGS) reaction were prepared with co-precipitation method, and the influence of ZrO2 content on the catalytic structure and properties was investigated by the techniques of... Cu/CeO2-ZrO2 catalysts for water-gas shift (WGS) reaction were prepared with co-precipitation method, and the influence of ZrO2 content on the catalytic structure and properties was investigated by the techniques of N2 physical adsorption analysis, XRD and H2-TPR. The results indicate that the BET surface areas of the catalysts are increased in varying degrees due to the presence of ZrO2. With increasing ZrO2 content, the pore size distribution is centered on 1.9 nm. ZrO2 can efficiently restrain the growth of Cu crystal particles. The appropriate amount of ZrO2 in the Cu/CeO2 catalysts can help the catalyst keep better copper dispersion in the WGS reaction, which can lead to both higher catalytic activity and better thermal stability. When ZrO2 content is 10% (atom fraction), Cu/CeO2-Zr02 catalyst reaches a CO conversion rate of 73.7% at the reaction temperature of 200℃. 展开更多
关键词 water-gas shift Cu/ceo2-ZrO2 catalyst rare earths
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