Regulating electronic structure of porous nickel nitride nanosheet arrays by cerium doping for energy-saving hydrogen production coupling hydrazine oxidation

Water electrolysis for energy-efficient H-2 production coupled with hydrazine oxidation reaction (HzOR) is prevailing, while the sluggish electrocatalysts are strongly hindering its scalable application. Herein, we schemed a novel porous Ce-doped Ni3N nanosheet arrays grown on nickel foam (Ce-Ni3N/NF) as a remarkable bifunctional catalyst for both hydrogen evolution reaction and HzOR. Significantly, the overall hydrazine splitting system can achieve low cell voltages of 0.156 and 0.671 V at 10 and 400 mA.cm(-2), and the system is remarkably stable to operate over 100 h continuous test at the high-current-density of 400 mA-cm(-2). Various characterizations prove that the porous nanosheet arrays expose more active sites, and more excellent diffusion kinetics and lower charge-transfer resistance, therefore boosting catalytic performance. Furthermore, density functional theory calculation reveals that the incorporation of Ce can effectively optimize the free energy of hydrogen adsorption and promote intrinsic catalytic activity of Ni3N.

Automated summary

In this study, a novel porous Ce-doped Ni3N nanosheet arrays were designed as a bifunctional catalyst for both hydrogen evolution reaction and hydrazine oxidation reaction. The catalyst showed remarkable performance with low cell voltages and high stability, which could be attributed to the exposed active sites and improved diffusion kinetics of the porous nanosheet arrays, as well as the promoted catalytic activity by Ce doping.