Effects of thermal treatment conditions on redox properties of ceriazirconia materials  

作　　者：Shanshan Li Jie Deng Jianli Wang Yaoqiang Chen Yun Li 

机构地区：[1]Key Laboratory of Green Chemistry&Technology,Ministry of Education,College of Chemistry,Sichuan University,Chengdu,610064,China [2]College of Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu,610500,China [3]Center of Engineering of Vehicular Exhaust Gases Abatement,Sichuan Province,Chengdu,610064,China [4]Center of Engineering of Environmental Catalytic Material,Sichuan Province,Chengdu,610064,China [5]Sinocat Environmental Technology Co.,Ltd.,Chengdu,611731,China

出　　处：《Journal of Rare Earths》2023年第12期1969-1975,I0005,共8页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (21972097);the National Engineering Laboratory for Mobile Source Emission Control Technology (NELMS2020A04)。

摘　　要：The nanostructures and redox properties of CeO_(2)-ZrO_(2)materials can be tuned via optimized thermal treatments.In this study,the CeO_(2)-ZrO_(2)-Y_(2)O_(3)-La_(2)O_(3)(CZ) materials were prepared by co-precipitation method and submitted to different thermal treatment conditions(atmosphere:nitrogen(N) and air(A);temperature(x):700,800 and 900℃).Due to the protective effects of the "in-situ-formed" carbon powder,treating the surfactants assisted-CZ precursors under N2atmosphere can keep the pore structures and then the CZ-N700 and CZ-N800 can achieve larger surface area than CZ-A700 and CZ-A800,respectively.In comparison,with high treatment temperature(900℃),the effects of thermal atmosphere on surface area can be ignored.However,the redox properties of CZ materials correlate closely with thermal treatment atmosphere and temperature simultaneously.As demonstrated by X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) characterizations,the N_(2)atmosphere facilitates the formation of Ce^(3+)without disturbing the mixing degree of Ce and Zr.Thereby the CZ-Nx materials exhibit superior reducibility than corresponding CZ-Ax materials.In additio n,the XRD and XPS results also demonstrate the formation of a more homogeneous CZ solid solution by Zr atoms rearrangement with temperature ignoring the atmosphere.As a result,the reducibility of CZ materials increases with the treatment temperature increasing and is not affected by the worsening of the textural properties.Specially,due to the synergistic effects of N_(2)atmosphere and high treatment temperature,the CZ-N900 shows the best reducibility.This improvement also emphasizes the important role of structural properties of CZ in explaining the temperature-dependent reducibility.

关 键 词：CeO_(2)-ZrO_(2)material Thermal treatment Atmosphere and temperature REDUCIBILITY Rare earths 

分 类 号：O643.36[理学—物理化学] X701[理学—化学]