Fabrication of a Ti-supported NiCo2O4 nanosheet array and its superior catalytic performance in the hydrolysis of ammonia borane for hydrogen generation

Abstract

The development of low-cost nanocatalysts with high activity, high stability and good reusability towards the hydrolysis of chemical hydrides for hydrogen generation is of great importance and significance in the field of hydrogen energy. In this work, a Ti-supported NiCo₂O₄ thin film nanosheet array (NiCo₂O₄/Ti) is fabricated by a facile method, and its catalytic performance in the hydrolysis of ammonia borane for hydrogen production is investigated. It is found that the turnover frequency (TOF) of NiCo₂O₄/Ti can reach 50.1 mol H₂ min⁻¹ (mol catalyst)⁻¹, which is the highest TOF value reported for noble-metal-free catalysts towards the hydrolysis of ammonia borane. The apparent activation energy of ammonia borane hydrolysis in the presence of the NiCo₂O₄/Ti catalyst is as low as ca. 17.5 kJ mol⁻¹. More importantly, the NiCo₂O₄/Ti catalyst can retain ca. 90% of its original catalytic activity after 10 cycles, exhibiting much improved durability and reusability in contrast to many nanocatalysts recently reported in the literature. Its high catalytic activity and low-cost, together with its good durability and reusability, enable NiCo₂O₄/Ti to be a strong catalyst candidate for the hydrolysis of ammonia borane for hydrogen production in the practical applications.