Single Ni-inserted Cu (1 1 1) surface: A DFT study of adsorption and reaction mechanisms of methanol steam reforming

Modeling of a bimetallic catalyst surface and DFT calculations of its adsorption capacity, as well as methanol steam reforming (MSR) pathways, are of great theoretical achievements in the search for efficient hydrogen-production catalysts. Herein, the single Ni-embedded model (NiCu(1 1 1)) and single Ni-adsorbed model (A-NiCu(1 1 1)) are built, and DFT calculations are carried out to determine different adsorption capabilities. The results show that adding Ni atoms can improve adsorption performance significantly, which is beneficial to the interaction between reactant molecules and catalyst surfaces. The adsorption energies on the A-NiCu(1 1 1) surface are much greater than those on the NiCu(1 1 1) surface. Further, some key elementary reactions of MSR are carried out to evaluate the catalytic performances and carbon deposition effects of two surfaces. The stepwise dehydrogenation of methanol molecules, the decomposition of water molecules, and other reactions of some intermediates are analyzed in detail. On the A-NiCu(1 1 1) surface, the activation energy barriers of stepwise dehydrogenation of methanol molecules and water decomposition are reduced. The NiCu(1 1 1) surface shows advantages in inhibiting the surface carbon deposition. This can provide theoretical ideas for the design of high-efficiency Cu-Ni alloy catalysts in the future.