One-pot synthesis of ultrafine Ni0.13Co0.87P nanoparticles on halloysite nanotubes as efficient catalyst for hydrogen evolution from ammonia borane

Abstract

Exploring low-cost and earth-abundant catalyst to efficiently release clean H2 from solid hydrogen storage materials is an appealing solution for exhausted fossil fuel and its associated environmental issue. Halloysite (Hal) nanotubes are regarded as promising alternative catalyst support for expensive synthetic support materials due to their low cost and abundant resource. Herein, we report a simple and controllable one-pot reaction followed by chemical reduction approach to manufacture Ni, Co, P hybrids on Hal as high-efficient and non-noble metal catalysts for hydrolysis of ammonia borane (AB). It is revealed that ultrafine Ni0.13Co0.87P nanoparticles with diameter of 1.4 nm are homogenously anchored on Hal surface with excellent stability. The synergy among Ni, Co and P in Ni0.13Co0.87P effectively enhances their interaction with AB, resulting in reduced activation energy (41.8 kJ mol−1) and consequently significant boost of hydrolytic catalytic activity (TOF 47.5 molH2 molcat−1 min−1). A proposed mechanism demonstrates water molecules involve in the hydrolysis reaction and the rate-determining step is the OH cleavage in H2O. This work affords a prospective idea for the exploiting of Hal as well as new point of view for the reasonable design of low-cost AB hydrolysis catalyst.