DFT study on the catalytic role of α-MoC(100) in methanol steam reforming

Abstract

In this work, we investigated the methanol steam reforming (MSR) reaction (CH3OH+H2O →CO2+3H2) catalyzed by α-MoC by means of density functional theory calculations. The adsorption behavior of the relevant intermediates and the kinetics of the elementary steps in the MSR reaction are systematically investigated. The results show that, on the α-MoC(100) surface, the O−H bond cleavage of CH3OH leads to CH3O, which subsequently dehydrogenates to CH2O. Then, the formation of CH2OOH between CH2O and OH is favored over the decomposition to CHO and H. The sequential dehydrogenation of CH2OOH results in a high selectivity for CO2. In contrast, the over-strong adsorption of the CH2O intermediate on the α-MoC(111) surface leads to its dehydrogenation to CO product. In addition, we found that OH species, which is produced from the facile water activation, help the O−H bond breaking of intermediates by lowering the reaction energy barrier. This work not only reveals the catalytic role played by α-MoC(100) in the MSR reaction, but also provides theoretical guidance for the design of α-MoC-based catalysts.