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High activity of CeO2-TiO2 composites for deep oxidation of 1,2-dichloroethane

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Journal of Rare Earths 2020年第8期38卷 906-911,I0003页

作者： Jialu Wang Zhinan Shi renxian zhou Institute of Catalysis Zhejiang UniversityHangzhou 310028PR China

CeO2-TiO2 catalysts prepared by different methods were investigated for deep oxidation of 1,2-dichloroethane(DCE),as a typical representative of the chlorinated volatile organic compounds(CVOCs).Characterization analysis reveals that CeO2-TiO2 catalysts prepared by sol-gel and coprecipitation methods exhibit higher specific area,CeO2 and TiO2 particles are highly dispersed into each other and the reducibility and mobility of active oxygen species are obviously promoted due to the strong interaction between the two catalysts CeO2 and TiO2,resulting in higher catalytic activity for DCE oxidation to and less chlorinated *** high calcination temperature would lead to the formation of a new monoclinic phase Ce0.3Ti0.7O2 and sintering,which is the main reason for the catalytic activity for DCE oxidation markedly decreases.

关键词： CeO2-TiO2 catalysts Synergism Chlorinated VOCs Catalytic oxidation Rare earths

Influence of rare-earth metal doping on the catalytic performance of CuO-CeO_2 for the preferential oxidation of CO in excess hydrogen

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Journal of Natural Gas Chemistry 2008年第3期17卷 283-287页

作者： Zhigang Liu renxian zhou Xiaoming Zheng Institute of Catalysis Zhejiang University Hangzhou 310028 Zhejiang China School of Chemistry and Chemical Engineering Hunan University Changsha 410082 Hunan China

Doping of different rare-earth metals （Pr, Nd, Y and La） had an evident influence on the catalytic performance of CuO-CeO2 for the preferential oxidation （PROX） of CO in excess hydrogen. As for Pr, the doping enhanced the catalytic activity of CuO-CeO2 for PROX. For example, the CO conversion over the above catalyst for PROX was higher than 99% at 120 °C. Especially, the doping of Pr widened the temperature window by 20 °C over CuO-CeO2 with 99% CO conversion. For Nd, Y, and La, the doping depressed the catalytic activity of CuO-CeO2 for PROX. However, the doping of transition metals markedly improved the selectivity of CuO-CeO2 for PROX.

关键词： CuO-CeO2 rare-earth metal doping CO

Preferential Oxidation of CO in Excess Hydrogen over CuO-CeO_2 Catalyst Prepared by Chelating Method

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Journal of Natural Gas Chemistry 2007年第2期16卷 167-172页

作者： Zhigang Liu renxian zhou Xiaoming Zheng Institute of Catalysis Zhejiang University Hangzhou 310028 Zhejiang China

The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. The CO conversions over these catalysts, at 120 ℃ and 120000 ml/（g-h） in the absence of CO2 and H2O, are 99.6% and 88.6%, respectively, and the selectivity of O2 over these catalysts is very close （i.e. 51.3% and 55.8%, respectively）. The influence of certain factors such as hydrogen concentration, carbon monoxide concentration, H2O, O2/CO ratios, and space velocity on the catalytic performance of CuO-CeO2 catalyst prepared by chelating method is also studied. The results show that the addition of hydrogen and H2O has a negative effect on the catalytic performance of CuO-CeO2 catalyst, however, the variation of space velocity and the O2/CO ratio causes a comparatively slight influence.

关键词： CuO-CeO2 chelating method preferential oxidation CO hydrogen

The size effect and high activity of nanosized platinum supported catalysts for low temperature oxidation of volatile organic compounds

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Chinese Journal of Chemical Engineering 2021年第11期34卷 135-143页

作者： Ziqing Yuan Ziyu Chen Jianxin Mao renxian zhou Institute of Catalysis Zhejiang UniversityHangzhou 310028China

Pt/Al_(2)O_(3) catalysts with smaller size of Pt nanoparticles were prepared by ethylene glycol reduction method in two different way and their oxidation activities for three typical VOCs(volatile organic compounds)were *** catalyst prepared by first adsorption and then reduction procedure is denoted as L-Pt/Al_(2)O_(3) while the catalyst prepared by first reduction and then loading procedure is defined as R-Pt/Al_(2)O_(3).The results show that L-Pt/Al_(2)O_(3) with the stronger interaction between Pt species and Al_(2)O_(3) exhibit smaller size of Pt nanoparticles and favorable thermal stability compared with R-Pt/Al_(2)O_(3).L-Pt/Al_(2)O_(3) is favor of the formation of more adsorbed oxygen species and more Pt^(2+)species,resulting in high catalytic activity for benzene and ethyl acetate ***,R-Pt/Al_(2)O_(3) catalysts with higher proportion of Pt^(0)/Pt^(2+)and bigger size of Pt particles exhibits higher catalytic activity for n-hexane *** particles in R-Pt/Al_(2)O_(3) were aggregated much more serious than that in L-Pt/Al_(2)O_(3) at the same calcination *** Pt particles supported on Al_(2)O_(3) with~10 nm show the best catalytic activity for n-hexane oxidation.

关键词： Environment Particle size distribution Catalysis Thermal stability Size effect of Pt

One-pot synthesis of Fe/Cu-SSZ-13 catalyst and its highly efficient performance for the selective catalytic reduction of nitrogen oxide with ammonia

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Journal of Environmental Sciences 2021年第2期33卷 306-316页

作者： Jie Wan Jiawei Chen Ru Zhao renxian zhou Energy Research Institute Nanjing Institute of TechnologyNanjing 211167China Institute of Catalysis Zhejiang UniversityHangzhou 310028China

Series of Fe/Cu-SSZ-13 catalysts with different Fe loading content were synthesized by simple one-pot *** obtained catalysts were subjected to selective catalytic reduction(SCR)of NO x with NH 3 and were characterized by various *** results show that Fe 0.63/Cu 1.50-SSZ-13 catalyst with proper Fe content exhibits excellent catalytic activity with widest operation temperature window from 160 to 580℃,excellent hydrothermal stability as well as good resistance to sulfur poisoning when compared with Cu-SSZ-13,signifying its great potential for practical *** characterizations reveal that the synthesized Fe/Cu-SSZ-13 catalysts present typical chabazite(CHA)structure with good crystallinity,while isolated Cu^2+and monomeric Fe 3+are revealed as the predominant copper and iron *** low temperatures,isolated Cu^2+species act as primary active sites for SCR reaction,while monomeric Fe^3+species provide sufficient active sites for sustain the SCR activity at high ***,Fe over doping would lead to the damage of zeolite structure,destruction of isolated Cu^2+site,as well as the formation of highly oxidizing Fe2O3,thus causing deterioration of catalytic performances.

关键词： NH3-SCR Fe/Cu-SSZ-13 One-pot synthesis Active species

Synergistic effect of Pt nanoparticles and micro-mesoporous ZSM-5 in VOCs low-temperature removal

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Journal of Environmental Sciences 2021年第9期33卷 87-97页

作者： Jialu Wang Xiaolin Guo Yijun Shi renxian zhou Institute of Catalysis Zhejiang UniversityHangzhou 310028China College of Materials and Chemistry China Jiliang UniversityHangzhou 310018China

Micro-mesoporous ZSM-5 zeolites were obtained by the post-treatment of tetrahydroxy ammonium hydroxide(TPAOH) solution with different *** hierarchical pore structure formed during the desilication process facilitates the dispersion of Pt nanoparticles and Pt/ZSM-5 catalysts exhibit rather high catalytic activity for the deep oxidation of various VOCs at low *** catalyst treated with TPAOH of 0.1 mol/L(Pt/ZSM-5(0.1)) shows the lowest degradation temperature(T90%) of 128 and 142℃, respectively for benzene and *** with the untreated Pt/ZSM-5 catalyst, the abundant mesopores, small Pt particle size and finely dispersed Pt contribute to the superior catalytic activity and stability of the Pt/ZSM-5 catalysts for VOCs *** importantly, the existence of H_(2)O in the feed gases hardly affected the activity of Pt/ZSM-5(0.1) catalyst at the low reaction temperature of 128℃, which is very important for VOCs low-temperature removal in the future practical applications.

关键词： Pt/ZSM-5 catalysts Micro-mesoporous ZSM-5 VOC oxidation Synergistic effect

Influence of preparation methods on CuO-CeO_2 catalysts in the preferential oxidation of CO in excess hydrogen

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Journal of Natural Gas Chemistry 2008年第2期17卷 125-129页

作者： Zhigang Liu renxian zhou Xiaoming Zheng School of Chemistry and Chemical Engineering Hunan University Changsha 410082 China Institute of Catalysis. Zhejiang University Hangzhou 310028 China

Influence of three different preparation methods, i.e. impregnation, coprecipitation, and inverse coprecipitation, on the preferential oxidation of CO in excess hydrogen （PROX） over CuO-CeO2 catalysts has been investigated and CuO-CeO2 catalysts are characterized using BET, XPS, XRD, UV Raman, and TPR techniques. The results show that the catalysts prepared by coprecipitation have smaller particle sizes, well-dispersed CuOx species, more oxygen vacancies, and are more active in the PROX than those prepared by the other methods. However. the inverse coprecipitation depresses the catalytic performance of CuO-CeO2 catalysts and causes the growth of CuO-CeO2 because of different pH value in the precipitation process.

关键词： CuO-CeO2 preparation method preferential oxidation CO fuel cell

Transition metaldoping effect and high catalytic activity of CeO_(2)-TiO_(2) for chlorinated VOCs degradation

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Journal of Rare Earths 2022年第5期40卷 745-752,I0003页

作者： Yijun Shi Xiaolin Guo Zhinan Shi renxian zhou Institute of Catalysis Zhejiang UniversityHangzhou 310028China College of Materials and Chemistry China Jiliang University Hangzhou 310018China

A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs(CVOCs).The various characterization methods including X-ray diffraction(XRD),N_(2) adsorption-desorption,UV-Raman,NH_(3) temperature-programmed desorption(NH_(3)-TPD) and H_(2) temperature-programmed reduction(H_(2)-TPR) were utilized to investigate the physicochemical properties of the *** results show that doping Fe,Co,Ni or Mn can obviously promote the activity of CeO_(2)-TiO_(2) mixed oxides for DCE degradation,which is related to their improved texture properties,acid sites(especially for strong acidity) and low-temperature ***,CeTi-Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane(DCE) degradation,giving a T_(90%) value as low as 250℃.More importantly,only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs(dichloromethane(DCM),trichloroethylene(TCE) and chlorobenzene(CB)) over CeTi-Fe1/9 catalyst with high durability.

关键词： Transition metals doping CeO_(2)-TiO_(2)mixed oxides CVOCs degradation High activity Excellent durability Rare earths

Low-temperature VOCs oxidation performance of Pt/zeolites catalysts with hierarchical pore structure

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Journal of Environmental Sciences 2023年第2期124卷 505-512页

作者： Jialu Wang Yijun Shi Fanzhe Kong renxian zhou Institute of Catalysis Department of ChemistryZhejiang UniversityHangzhou 310028China

Different zeolites supported Pt catalystswithmicro-mesoporous structurewere prepared by organic base tetrapropylammonium hydroxide(TPAOH)treatment and their catalytic oxidation activity for various volatile organic compounds(VOCs)were *** results reveal that the synergistic effect between Pt nanoparticles and surface acid sites plays an important role in VOCs low-temperature *** small size and high dispersion of Pt nanoparticles on the surface of the zeolites would promote the catalytic oxidation of aromatics and alkanes over the Pt/zeolite catalysts,while strong acidity and abundant acid sites of catalysts are in favour of the oxidation of the VOCs *** addition,it was found that Pt/ZSM-5 catalyst exhibits the highest oxidation activity for various VOCs low-temperature removal amongst all the catalysts due to the balance of both Pt dispersion and abundant acid sites in the *** comprehensive consideration should be very helpful when designing and preparing novel catalysts for the low-temperature removal of VOCs.

关键词： Pt/zeolites catalyst Hierarchical pore zeolites VOCs oxidation Synergistic effect