A comprehensive DFT study of CO2 methanation on the Ru-doped Ni(111) surface

Ru−Ni bimetallic catalysts show excellent performance for CO2 methanation, but the underlying mechanism remains unclear. In this study, the mechanism of CH4 synthesis on Ru-doped Ni(111) is investigated with the density functional theory methods. Through the discussion of the adsorption of all possible species, the relatively weak O* adsorption indicates that the introduction of Ru into the Ni catalyst can effectively protect the Ni active sites from being oxidized. Meanwhile, the partial density of states analyses reveals that CO2* is well activated on the catalyst. In addition, the optimal route for CO2 hydrogenation into CH4 is obtained, with an activation barrier of 1.13 eV for the rate-determining step. It shows that Ru-doped Ni(111) possesses superior catalytic activity for CO2 hydrogenation to CH4. Additionally, the activation barriers of all the surface C* formation reactions significantly increase, manifesting that the resistance to carbon deposition of Ru-doped Ni(111) is improved. [Display omitted] •The reaction mechanism of CO2 methanation on Ru-doped Ni(111) is studied by DFT.•The rate-determining step has a relatively small activation barrier of 1.13 eV.•Carbon deposition on Ru-doped Ni(111) is effectively suppressed.