Supported nickel–iron nanocomposites as a bifunctional catalyst towards hydrogen generation from N2H4·H2O

Hydrogen represents an important alternative energy feedstock for both environmental and economic reasons. Development of highly selective, efficient and economical catalysts towards H2 generation from hydrogen storage materials (e.g., hydrous hydrazine, N2H4·H2O) has been one of the most active research areas. In this work, a bifunctional NiFe-alloy/MgO catalyst containing both an active center and a solid base center was obtained via a calcination–reduction process of NiFeMg-layered double hydroxides (LDHs) precursor, which exhibits 100% conversion of N2H4·H2O and up to 99% selectivity towards H2 generation at room temperature, comparable to the most reported noble metal catalysts (e.g., Rh, Pt). The XRD, HRTEM and HAADF-STEM results confirm that well-dispersed NiFe alloy nanoparticles (NPs) with diameters of ∼22 nm were embedded in a thermally stable MgO matrix. The EXAFS verifies the electronic interaction between nickel and iron elements in NiFe alloy NPs, accounting for the significantly enhanced low-temperature activity. The CO2-TPD results indicate that the strong basic sites on the surface of the NiFe-alloy/MgO catalyst contribute to the high H2 selectivity.