Highly active K-promoted Cu/β-Mo2C catalysts for reverse water gas shift reaction: Effect of potassium

The K-promoted Cu/beta-Mo2C catalysts with different K loadings were prepared for the reverse water gas shift (RWGS) reaction. The results showed that the incorporation of potassium into the Cu/beta-Mo2C catalyst significantly increased CO2 conversion and CO selectivity at an optimal K loading. The remarkable catalytic performance of the 1K-Cu/Mo2C catalyst was due to the presence of highly dispersed Cu nanoparticles and the improved CO2 activation and dissociation caused by the structural and electronic effect of potassium. The presence of K also suppresses H-2 adsorption and inhibits the methanation of CO2. The gas switching experiments and in-situ DRIFTS analyses suggest that both the redox and associative mechanism coexists in the RWGS reaction and that the formate species act as the intermediates in converting CO2 to CO for the K-promoted Cu/beta-Mo2C catalysts.