Engineering Bimodal Oxygen Vacancies and Pt to Boost the Activity Toward Water Dissociation

Water dissociation is the rate-limiting step of several energy-related reactions due to the high energy barrier required for breaking the oxygen-hydrogen bond. In this work, a bimodal oxygen vacancy (V-O) catalysis strategy is adopted to boost the efficient water dissociation on Pt nanoparticles. The single facet-exposed TiO2 surface and NiOx nanocluster possess two modes of V-O different from each other. In ammonia borane hydrolysis, the highest catalytic activity among Pt-based materials is achieved with the turnover frequency of 618 min(-1) under alkaline-free conditions at 298 K. Theoretical simulation and characterization analyses reveal that the bimodal V-O significantly promotes the water dissociation in two ways. First, an ensemble-inducing effect of Pt and V-O in TiO2 drives the activation of water molecules. Second, an electron promoter effect induced by the electron transfer from V-O in NiOx to Pt further enhances the ability of Pt to dissociate water and ammonia borane. This insight into bimodal V-O catalysis establishes a new avenue to rationally design heterogeneous catalytic materials in the energy chemistry field.