【摘要】 采用草酸盐热分解-浸渍法制备了一系列不同CuO负载量的CuO/CeO₂催化剂,并将其用于CO优先氧化（PROX）研究.当CuO负载量为10%时催化剂活性最高,具有温区最宽且温度最低的CO完全转化窗口（96¹60℃）,并且当反应温度低于131℃时,产物中CO2选择性始终保持100%.研究结果表明,当负载少量CuO时,Cu²⁺离子会进入CeO₂晶格形成固溶体;进一步提高CuO负载量会导致CuO在CeO₂表面聚集.对于CuO/CeO₂催化剂,形成Cu-Ce固溶体会在催化剂表面生成大量的表面氧空位和Ce3+;Ce3+则与Cu²⁺作用产生更多的表面Cu⁺,而Cu⁺是CO PROX的活性中心,因此表面Ce3+含量的提高和Cu-Ce之间相互作用的增强是活性提高的主要原因.与普通沉淀-浸渍法制备的CuO/CeO₂催化剂相比,草酸盐热分解-浸渍法制备的催化剂更有利于Cu-Ce固溶体的形成,从而具有更多的表面Ce3+和更强的表面Cu-Ce相互作用,因此具有更高的CO优先氧化活性.更多还原

【Abstract】 A series of CuO/CeO₂ catalysts with different CuO loadings was prepared via oxalate thermal decomposition-impregnation method for the CO preferential oxidation（PROX） reaction.The catalyst with 10%CuO loading has the best activity,with the lowest and the widest CO full conversion temperature window of 96—160 ℃,and 100% selectivity to CO₂ below 131℃.The results indicate that the Cu-Ce solid solution is formed when a small amount of CuO is loaded.However,the increased CuO loading will result in the aggregation of CuO on the surface of CeO₂,which is unfavorable to form the solid solution.For the CuO/CeO₂ catalysts,the formation of Cu-Ce solid solution can inevitably generate surface oxygen vacancy and Ce³⁺,which can react with the Cu²⁺ to produce Cu⁺ through the balance of Ce³⁺+Cu²⁺Ce⁴⁺+Cu⁺.As the Cu⁺is the active center for the CO PROX,the increased surface Ce³⁺content and the strengthened interaction between CuO and CeO₂ can enhance the CO PROX activity of the catalyst.Compared with the CuO/CeO₂ catalysts prepared by precipitation-impregnation method,the catalysts prepared by oxalate thermal decompositionimpregnation method have the higher surface Ce³⁺ content and stronger interaction between Cu and Ce,resulting in the better CO PROX activity.更多还原