Nickel-palladium nanoparticle catalyzed hydrogen generation from hydrous hydrazine for chemical hydrogen storage

Abstract

In this study, we report Ni-Pd bimetallic nanoparticle catalysts (nanocatalyst) (Ni 1-xPd x) synthesized by alloying Ni and Pd with varying Pd contents, which exhibit appreciably high H 2 selectivity (>80% at x = 0.40) from the decomposition of hydrous hydrazine at mild reaction condition with Ni 0.60Pd 0.40 nanocatalyst, whereas the corresponding monometallic counterparts are either inactive (Pd nanoparticles) or poorly active (Ni nanoparticles exhibit 33% H 2 selectivity). In addition to powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) analysis and electron microscopy (TEM/SEM), the structural and electronic characteristics of Ni-Pd nanocatalysts were investigated and established using extended X-ray absorption fine structure (EXAFS) analysis. Unlike the high activity of Ni-Pd nanocatalysts, Pd-M (M = Fe, Co and Cu) bimetallic nanocatalysts exhibit poor catalytic activity. These results imply that alloy composition of Ni-Pd nanocatalysts is critical, where the co-existence of both the metals on the catalyst active surface and the formation of inter-metallic Ni-Pd bond results in high catalytic performance for the decomposition of hydrous hydrazine to hydrogen.