Unraveling the role of support surface hydroxyls and its effect on the selectivity of C2 species over Rh/γ-Al2O3 catalyst in syngas conversion:A theoretical study
The supported Rh-based catalysts exhibit the excellent catalytic performances for syngas conversion to C2 species.In this study,all possible elementary steps leading to C2 species from syngas have been explored to identify the role of support and its surface hydroxyls over Rh/γ-Al2O3 catalyst; Here,the results are obtained using density functional theory(DFT)method.Two models: Rh4 cluster supported on the dry γ-Al2O3(110)surface,D(Rh4),and on the hydroxylated γ-Al2O3(110)surface,H(Rh4),have been used to model Rh/γ-Al2O3 catalyst.Our results show that CO prefers to be hydrogenated to CHO,subsequently,starting from CHO species,CH and CH2 species are the dominate monomers among CHx(x = 1–3)species rather than CH3 and CH3OH on D(Rh4)and H(Rh4)surfaces,suggesting that γ-Al2O3-supported Rh catalyst exhibits the high selectivity towards CHx formation compared to the pure Rh catalyst.On the other hand,D(Rh4)is more favorable for C2 hydrocarbon(C2H2)formation,whereas H(Rh4)surface easily produces C2 hydrocarbon(C2H2)and C2 oxygenates(CHCO,CH2CHO),indicating that the surface hydroxyls of support can affect the selectivity of C2 species over Rh/γ-Al2O3 catalyst in syngas conversion.Moreover,compared to the pure Rh(111)surface,Rh/γ-Al2O3 catalyst can achieve the excellent catalytic performances for syngas conversion to C2 species.
Rh/γ-Al2O3 Syngas conversion Hydroxylation C2 oxygenates C2 hydrocarbons Density functional theory
Riguang Zhang Tian Duan Baojun Wang Lixia Ling
Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China
国内会议
大连
英文
643-653
2016-09-24（万方平台首次上网日期，不代表论文的发表时间）