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分别采用沉淀法(A),水热法(B)和柠檬酸溶胶-凝胶法(C)制备了三种CeO2材料,并以其为载体采用沉积-沉淀法制备了CuO/CeO2催化剂.运用N2物理吸附、粉末X射线衍射(PXRD)、原位粉末X射线衍射(insituPXRD)、氢气-程序升温还原(H2-TPR)和循环伏安法(CV)等技术对其进行了表征,考察了不同方法制备的CeO2载体对CuO/CeO2水煤气变换(WGS)催化剂的结构、氧化-还原性能、催化活性和稳定性的影响.结果表明,它们的催化活性和稳定性顺序都是CuO/CeO2-A>CuO/CeO2-B>CuO/CeO2-C.联系表征结果,CuO/CeO2催化剂的活性与催化剂中CuO的颗粒度、CuO的微观应力和中等大小且与二氧化铈相互作用的CuO的数量等有关,而这些因素很大程度上受CeO2载体本身的热稳定性的影响.根据CV中扫描次数的增加,Cu2+圮Cu0氧化还原峰面积减小,推断CuO/CeO2催化剂在一定条件下氧化还原是不可逆的,这可能是其在反应气氛下经受温度循环之后活性降低的原因.
Three kinds of CeO2 materials were prepared by precipitation method (A), hydrothermal method (B) and citric acid sol-gel method (C) respectively, and CuO / CeO2 catalysts were prepared by precipitation- N2 physisorption, PXRD, insituPXRD, H2-TPR and cyclic voltammetry (CV) were used to investigate the effects of The effects of CeO2 support prepared by different methods on the structure, oxidation-reduction performance, catalytic activity and stability of CuO / CeO2 water-gas shift (WGS) catalysts were investigated. The results showed that their catalytic activity and stability order were CuO / CeO2-A > CuO / CeO2-B> CuO / CeO2-C. In relation to the characterization results, the activity of the CuO / CeO2 catalyst is related to the particle size of CuO in the catalyst, the micro-stress of CuO and the amount of CuO with medium size and with ceria , And these factors are largely affected by the thermal stability of the CeO2 support.According to the increase in the number of CVs in the scan, the redox peak area of Cu2 + 圮 Cu0 decreases. It is deduced that the redox state of the CuO / CeO2 catalyst under certain conditions is Irreversible, it may be that it is subjected to temperature in a reactive atmosphere Causes of reduction in activity after cycling.