Valorization of carbon dioxide into C1 product via reverse water gas shift reaction using oxide-supported molybdenum carbides

Abstract

Conversion of carbon dioxide (CO 2 ) to C1 products such as carbon monoxide (CO) is a critical step towards carbon valorization. The conversion has been largely carried out through the reverse water gas shift (RWGS) reaction using noble metal catalysts or copper-based nanostructures. Similarities in the electronic structures between beta phase molybdenum carbides (β-Mo 2 C) and platinumgroup metals make them promising alternatives to traditional catalysts. In this work, we studied the effect of oxide supports (MO x , M = Al, Ce, Mg, Si, and Ti) on the formation and g −1 Mo2C g −1 Mo2C catalytic properties of β-Mo 2 C nanoparticle catalysts. The β-Mo 2 C/SiO 2 catalyst exhibited a mass activity of 372 μmol CO 2 ••s −1 at 400 °C and 1109 μmol CO 2 • •s −1 at 600 °C for the conversion of CO 2 . The β-Mo 2 C/SiO 2 catalysts also maintained selectivity and showed structural stability in the on-stream study. The enhanced catalytic performance could be attributed to the size of nanocatalysts (4.7 nm), whereas the stability is related to the interaction with SiO 2 and the low H 2 :CO 2 feed ratio. This work highlights the application of amorphous silica in preparing metal carbide nanocatalysts. The rich defects and surface vacancies in the silica support greatly facilitate the highrate and highly selective processes towards the valorization of CO 2 .