Realizing the Synergy of Interface Engineering and Chemical Substitution for Ni3N Enables its Bifunctionality Toward Hydrazine Oxidation Assisted Energy-Saving Hydrogen Production

Hydrazine oxidation assisted water electrolysis offers a unique rationale for energy-saving hydrogen production, yet the lack of effective non-noble-metal bifunctional catalysts is still a grand challenge at the current stage. Here, the Mo doped Ni3N and Ni heterostructure porous nanosheets grow on Ni foam (denoted as Mo-Ni3N/Ni/NF) are successfully constructed, featuring simultaneous interface engineering and chemical substitution, which endow the outstanding bifunctional electrocatalytic performances toward both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER), demanding a working potential of -0.3 mV to reach 10 mA cm(-2) for HzOR and -45 mV for that of HER. Impressively, the overall hydrazine splitting (OHzS) system requires an ultralow cell voltage of 55 mV to deliver 10 mA cm(-2) with remarkable long-term durability. Moreover, as a proof-of-concept, economical H-2 production systems utilizing OHzS unit powered by a waste AAA battery, a commercial solar cell, and a homemade direct hydrazine fuel cell (DHzFC) are investigated to inspire future practical applications. The density functional theory calculations demonstrate that the synergy of Mo substitution and abundant Ni3N/Ni interface owns a more thermoneutral value for H* absorption ability toward HER and optimized dehydrogenation process for HzOR.

Automated summary

The Mo doped Ni3N and Ni heterostructure porous nanosheets grown on Ni foam demonstrate outstanding bifunctional electrocatalytic performances towards hydrazine oxidation reaction and hydrogen evolution reaction.