MoOx-modified bimetallic alloy nanoparticles for highly efficient hydrogen production from hydrous hydrazine

Abstract

Hydrogen has been considered as an important alternative energy source for both environmental and economic reasons. The development of highly efficient and selective catalysts for hydrogen evolution from chemical hydrogen storage materials (e.g. hydrous hydrazine, N₂H₄·H₂O) has become one of the most active research areas. In this study, MoO_x-doped NiPt nanoparticles (NPs) have been successfully prepared via a simple one-step co-reduction strategy at room temperature. The characterization results show that the surfactant/support-free NiPt–MoO_x NPs with a mean particle size of 5.0 nm are well-dispersed and in a low-crystalline/amorphous state. It is found that the prepared NiPt–MoO_x samples show much higher catalytic activity toward the decomposition of N₂H₄ as compared to that of NiPt without the introduction of MoO_x. In addition, among all the NiPt–MoO_x NPs, the optimized Ni_0.6Pt_0.4–MoO_x nanocatalyst shows 100% H₂ selectivity and the best catalytic performance for the decomposition of N₂H₄ under alkaline conditions at 323 K. The TOF value of Ni_0.6Pt_0.4–MoO_x NPs is found to be 822 h⁻¹, which is among the highest values ever report for the same reaction. The excellent catalytic activities could be attributed to the modified electronic structure and the small particle size of NiPt NPs induced by the MoO_x dopant. Other MoO_x-doped Ni-based (NiM, M = Rh, Ir, Au, Ag and Ru) bimetallic catalysts also showed excellent catalytic activity. The present highly efficient and selective catalyst system may encourage the practical application of N₂H₄·H₂O as a potential chemical hydrogen storage material.