Promoting Effect of Heterostructured NiO/Ni on Pt Nanocatalysts toward Catalytic Hydrolysis of Ammonia Borane.

Abstract

We report that heterostructured NiO/Ni nanoparticles remarkably promote the catalytic H2 production of platinum (Pt) nanoclusters toward the hydrolysis of ammonia borane (AB). A hybrid nanocatalyst composed ultrasmall Pt nanoclusters, heterostructured NiO/Ni nanoparticles, and a carbon nanotube support (defined as Pt@NiO/Ni-CNT) is fabricated. The resultant Pt@NiO/Ni-CNT is highly efficient for room-temperature H2 production toward catalytic hydrolysis of AB, better than the Pt@NiO-CNT and Pt@Ni-CNT with NiO or Ni alone, and the Pt@NiO/Ni without CNT support. Optimal Pt@NiO/Ni-CNT catalyst exhibits a good catalytic activity with a high TOF of 2665 molH2 molPt-1 min-1 under ambient conditions, overtaking the activities of previously reported catalysts for AB hydrolysis. Catalytic kinetic studies indicate that compositional and structural features of the Pt@NiO/Ni-CNT synergistically accelerate the oxidative clearage of the H-OH bond from attacked H2O (the rate-determining step), thus boosting catalytic hydrolysis of AB kinetically.