Highly Dispersed CuNi Nanoparticles Supported on Reduced Graphene Oxide as Efficient Catalysts for Hydrogen Generation from NH3BH3

Abstract

Abstract Highly dispersed CuNi nanoparticles (NPs) immobilized on reduced graphene oxide (RGO) were synthesized via the simple in situ co-reduction of an aqueous solution of Copper(II) sulfate pentahydrate, nickel chloride hexahydrate, and graphene oxide (GO) by the reduction of ammonia borane (AB) at room temperature. The powder XRD, FTIR, EDS, and TEM techniques were used to charaterize the structure, size, and composition of the CuNi/RGO catalysts. The as-prepared CuNi/RGO catalysts showed excellent catalytic performance toward the hydrolysis of AB at room temperature. Compared to Cu/RGO, Ni/RGO, and the RGO-free Cu0.6Ni0.4 counterpart, the as-prepared Cu0.6Ni0.4/RGO catalysts showed much better catalytic activity. Furthermore, kinetic studies showed that the catalytic hydrolysis of AB by Cu0.6Ni0.4/RGO has zero order dependence on the AB concentration, but first order dependence on the catalyst concentration. The turnover frequency (TOF) of Cu0.6Ni0.4/RGO catalyst for the hydrolytic dehydrogenation of AB was determined to be about 20.2 mol H2 (mol Cu0.6Ni0.4/RGO)−1 min−1 at 25 °C. In addition, the activation energy (Ea ) of Cu0.6Ni0.4/RGO was determined to be around 17.7 kJ mol−1, which is one of the lowest activation energy’s of the reported metal-based catalysts.