A theoretical study of the reverse water-gas shift reaction on Ni(111) and Ni(311) surfaces

This paper presents a systematic comparison study of the surface redox reaction mechanism for reverse water-gas shift (RWGS) over Ni(111) and Ni(311) surfaces. Specifically, the most stable surface intermediates and the reaction kinetics involved in the direct CO2 activation and water formation steps are computed with density functional theory calculations and compared for the two different Ni surfaces. The results show that CO2, CO, O, H, OH, and H2O species adsorb stronger on Ni(311) than on Ni(111). Compared to Ni(111), the overall barriers for direct CO2 activation and water formation on Ni(311) are lower by 23 and 17kJ/mol, respectively. These observations indicate that the RWGS reaction through the surface redox mechanism should be preferred on Ni(311).