Ni nanoparticles supported on graphitic carbon nitride as visible light catalysts for hydrolytic dehydrogenation of ammonia borane.

The development of a robust and low-cost non-noble metal catalyst for photocatalytic H2 evolution is of great importance for practical applications. In this study, monodisperse Ni nanoparticles of controlled sizes were prepared by a facile method and anchored on graphitic carbon nitride (g-C3N4) nanosheets via a self-assembly route. The noble-metal-free Ni/g-C3N4 composite catalysts exhibit excellent photocatalytic activities for the hydrolytic dehydrogenation of ammonia borane (AB) under visible light. An optimum AB hydrolysis rate was obtained when the size of the Ni NPs was 3.2 nm, with an initial turnover frequency of 18.7 mol(hydrogen) mol(catalyst)-1 min-1 and an apparent activation energy of 36 kJ mol-1. This study provides validity for constructing high performance first-row transition metal nano-photocatalysts for the hydrolytic dehydrogenation of AB.