金基二元合金团簇Au_(12)M(M=Cu,Pt,Ni)催化水煤气变换反应的理论研究

Catalysis Theoretical Study on Water Gas Shift Reaction of Au-based Binary Alloy Au_(12)M(M = Cu,Pt,Ni)

利用密度泛函理论(DFT)对Au12M(M=Cu,Pt,Ni)3种合金团簇的结构稳定性、热力学稳定性和反应活性进行研究,并对金基二元合金团簇催化水煤气变换反应(WGSR)的反应机理进行探讨.研究发现,Au12Ni合金团簇的稳定性及电子活性最优.考察了WGSR在金基二元合金团簇上的氧化还原机理和羧基机理,表明Au12Cu合金团簇上WGSR按照氧化还原机理A进行,水解离后产生的OH*会继续解离为O*和H*(*代表吸附物质);Au12Pt及Au12Ni合金团簇上按照氧化还原机理B进行,2个OH*发生歧化反应.比较3种团簇上的最佳反应路径发现,Au12Cu团簇对WGSR表现出较好的催化活性.

The structural stability,thermodynamic stability and reactivity of Au12 M（ M = Cu,Pt,Ni） alloy clusters doped with Cu,Pt and Ni were studied by density functional theory（ DFT） calculations. The reaction mechanism of water gas shift reaction（ WGSR） in gold-based binary alloy clusters was also discussed. The Au12 Ni alloy clusters were found to have the best stability and electron activity. The reaction mechanism of redox mechanism and carboxyl mechanism in gold-based binary alloy clusters was explored. The result shows that the WGSR on the Au12 Cu alloy is in accordance with the redox mechanism A,those on Au12 Pt and Au12 Ni alloy clusters are in accordance with the redox mechanism B. Comparing the optimal reaction path of the three clusters,Au12 Cu clusters show the best catalytic activity for WGSR.