Directional interfacial electron transfer in monolithic SnO2-Cu2O electrodes for accelerated ammonia electrooxidation and hydrogen recovery

With the continued expansion of the ammonia industry, electrochemically decomposing ammonia to generate hydrogen-rich gas streams for use in NH 3 -H 2 mixed fuel systems has become an important pathway for efficient ammonia resource utilization and green hydrogen production. A self-supported SnO 2 -Cu 2 O nanosheet electrode on nickel foam was developed as an efficient, stable, non-precious-metal anode for the ammonia oxidation reaction (AOR), enabling ammonia-assisted hydrogen production. The interconnected 3D nanosheet network offers good electrolyte penetration and gas release, while interfacial electronic interaction between SnO 2 and Cu 2 O induces charge redistribution that shifts the d-band center upward, lowering the *NH→*N dehydrogenation barrier to just 0.16 eV. This electronic regulation accelerates AOR kinetics, allowing the electrode to reach 50 mA cm −2 at only 1.46 V (vs. RHE) with over 60 h of stable operation. The catalyst also maintains high N 2 selectivity while suppressing NO x byproduct formation. Combined experimental and DFT analyses confirm that interface engineering between the two oxides is key to improving nitrogen intermediate evolution and overall catalytic performance. This work offers a practical strategy for designing durable, non-precious-metal AOR anodes, advancing electrochemical ammonia conversion technologies relevant to hydrogen generation from NH 3 -H 2 fuel systems.