Superior catalytic performance of non-stoichiometric solid solution Ce1 − xCuxO2 − δ supported copper catalysts used for CO preferential oxidation
Superior catalytic performance of non-stoichiometric solid solution Ce1 − xCuxO2 − δ supported copper catalysts used for CO preferential oxidation
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DOI：
10.1016/j.fuproc.2014.03.002
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发表时间：
2014-08
影响因子：
7.5
通讯作者：
Lijuan Yang;Shu-Yang Zhou;T. Ding;M. Meng
中科院分区：
文献类型：
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作者：
Lijuan Yang;Shu-Yang Zhou;T. Ding;M. Meng
采用共沉淀法和沉积-沉淀法分别制备了Ce1、−、CuxO2、−、δ系列非化学计量比固溶体及其负载型铜催化剂CuO/Ce1、−、−、δ(x=0、0.005、0.022、0.043)。CuO/Ce1、−、xCuxO2、−和δ催化剂对CO优先氧化(CO Prox)表现出较高的催化性能。采用氮气吸附(BET)、X射线衍射、激光拉曼光谱(LRS)、HRTEM、H2-TPR、O2-TPO、N2O化学吸附和原位漂移等多种技术对催化剂进行了表征。X-射线衍射仪、红外光谱和氢-热重分析结果表明，少量的Cu2+离子可以掺杂到CeO2的晶格中，形成非化学计量比的固溶体Ce1-−-xCuxO2-−-δ，表现出比纯CeO2更好的还原性能。负载型CuO/Ce1/−/CuxCuxO2/−-δ催化剂与CuO/CeO2相比，具有显著的催化活性，尤其是含15%铜的CuO/Ce0.978Cu0.022O2/−-δ催化剂表现出最佳的CO氧化性能，不仅表现出CO总转化的最低温度(115℃)，而且在此温度下O2向CO2的选择性为100%。该催化剂具有更多的氧空位、更好的还原能力和更强的CO化学吸附能力，这些都是其对CO Prox具有优异性能的原因。结果表明，Cu2+是CO氧化的主要活性中心，而Cu0对H2的活化和氧化活性较高。
A series of Ce1 − xCuxO2 − δnon-stoichiometric solid solutions and their supported copper catalysts CuO/Ce1 − xCuxO2 − δ(x = 0, 0.005, 0.022, 0.043) were prepared by co-precipitation and deposition–precipitation, respectively. The CuO/Ce1 − xCuxO2 − δcatalysts show high performance for CO preferential oxidation (CO PROX). Multiple techniques of N2sorption (BET), XRD, Laser Raman spectroscopy (LRS), HRTEM, H2-TPR, O2-TPO, N2O chemisorption and in-situ DRIFTS were used for catalyst characterization. The results of XRD, LRS and H2-TPR conformably indicate that a small amount of Cu2 +ions can be incorporated into the lattice of CeO2, forming non-stoichiometric solid solutions Ce1 − xCuxO2 − δ, which shows much better reducibility than pure CeO2. The supported CuO/Ce1 − xCuxO2 − δcatalysts exhibit remarkably enhanced activity for CO PROX as compared with CuO/CeO2, especially the catalyst CuO/Ce0.978Cu0.022O2 − δcontaining 15% Cu, which displays the best CO PROX performance, showing not only the lowest temperature (115 °C) for CO total conversion, but also the 100% selectivity of O2to CO2at this temperature. Several aspects including the presence of more oxygen vacancies, the improved reducibility, and stronger capability for CO chemisorption of this catalyst account well for its superior performance for CO PROX. Based upon the in-situ DRIFTS study, it is revealed that Cu+is the main active site for CO oxidation, while Cu0is more active for H2activation and oxidation.