Chitosan-reduced graphene oxide hybrids encapsulated Pd(0) nanocatalysts for H2 generation from ammonia borane

The hybrids consisting of chitosan (CS) and reduced graphene oxide (rGO) were assembled with an in-situ reduction strategy. Then, the resulting CS-rGO was used to encapsulate palladium nanoparticles (Pd NPs) via reducing PdCl2 with NaBH4. The mass ratios of CS to GO were optimized to increase the catalytic activity of the resultant Pd NPs/CS-rGO catalysts for the hydrolysis of ammonia borane (AB). The analytic results revealed that the Pd NPs (1.1-2.3 nm in diameter) were evenly encapsulated in the CS-rGO hybrids. Under the present conditions, the optimized Pd NPs/CS-rGO offered a high turnover frequency (TOF) value of 42.5 mol(H2) mol(Pd)(-1)min(-1). The activation energy of the AB hydrolysis was 39.02 kJ mor l and the corresponding orders of Pd and AB concentrations were 0.90 and 0.33, respectively. In addition, the Pd NPs/CS-rGO catalysts retain a stable hydrogen gen eration activity after four runs. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.