合成甲醇铜基催化剂上助催剂与铜原子相互作用对CO活化效应的量子化学

A Study of Metal-promoter Orbital Interactions and Promoter Effects on the CO Activation over Promoted Cu-based Catalysts for Mathanol Synthesis

应用电荷自洽离散变分X_近似计算方法,对周期表ⅣA～ⅧA族中各选一个过渡金属助催剂离子M^(n+)(=V^(3+),Ti^(3+),Fe^(3+),Mn^(2+),Mo^(4+))与合成甲醇铜基催化剂铜相互作用的本质及其对CO活化的效应进行量子化学研究,计算结果表明:以碳端基吸附在提出的含助催剂的铜基催化活性原子簇中心结构模型Cu_4MO的~1Cu上CO_得到助催剂M^(n+)的协合吸附,进一步减少了CO的键级;助催剂与催化剂铜间轨道的相互作用,影响铜的价态,增加金属d电子的反馈,改变吸附CO的态密度,从而促进CO的活化,文中还对比了不同助催剂,对CO的活化效应。

The naure of interactions between promoters, such as V3+, Ti3+ ,Fe3+ , Mn2+ ,Mo4+ ,and active center 1Cu atom of Cu-based catalysts for mathanol synthesis and promoter effects on the CO activation were investigated by selfconsistent charge-discrete variation-X, calculations. The results show that The bond-order of CO adsorbed on Cu-based catalysts model cluster Cu5 are less weaken than that on the promoted Cu-based catalysts model cluster Cu4MO. Metal-promoter orbital interactions have great effects on the vanlence states of active center 1Cu of catalysts, on adsorbed CO 2πn state density, on the ability of metal atoms to back-donation electrons into 2πn orbital of adsorbed CO over catalysts and hence on CO activation. The effects of different promoter on CO activation over promotred Cu-based catalysts have been studied.