Magnetic graphene oxide-ionic liquid grafted chitosan composites anchored Pd(0) nanoparticles: A robust heterogeneous catalyst with enhanced activity and superior reusability for hydrogen generation from ammonia borane

Magnetic solid materials may be separated easily from the solution by an external magnetic field and gain abundant applying opportunities. In this paper, magnetic composites are fabricated from ionic liquid grafted chitosan, graphene oxide, ferrous chloride and ferric chloride via a one-pot self-assembly combined with co-precipitation method. Then, the GO-ILCS-Fe3O4 composites are used as supports to anchor the in-situ reduced palladium nanoparticles (Pd(0) NPs). The results show that the Pd(0) NPs with a particle size distribution of 1.8-2.4 nm are dispersed well on GO-ILCS-Fe3O4 in the Pd(0)/GO-ILCS-Fe3O4 catalysts, which exhibit enhanced catalytic activity and superior reusability in the hydrogen generation from NH3BH3 (AB). The corresponding turnover frequency reaches up to 30.2 mol(H2).mol(pd)(-1).min(-1) and the reaction activation energy is as low as 32.6 kJ mol(-1). Moreover, the effects of catalyst dosage and AB concentration on the catalytic efficiency are also investigated. The results confirm that the palladium-based magnetic catalysts will be useful for the development of hydrogen generation. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.