Molybdenum carbide clusters for thermal conversion of CO2 to CO via reverse water-gas shift reaction

Abstract Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift (RWGS) reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster (the average size as small as 0.5 nm) are prepared via a facile carbothermal treatment for highly selective CO2-to-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μ mol g M o 2 C − 1 s − 1 at 400 °C with a superior selectivity toward CO (> 99.5%). This work highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.