The Ni–P dual vacancies crystalline/amorphous bifunctional electrode with ZnO “electron pump” for urea-assisted electrolysis of water to produce hydrogen

Electrochemical urea electrolysis holds great potential for energy-efficient hydrogen production and wastewater treatment . However, developing cost-effective and highly active catalysts remains a challenge. In this study, a novel bifunctional electrocatalyst of Ni–Zn bimetallic nanosheets (ZnO–Ni 2 P) was synthesized on Ni foam (NF) for efficient urea decomposition in urea-containing wastewater. The results showed that inactive ZnO phase acted as an "electron pump", which facilitated electron redistribution between Ni and P atoms and created localized vacancies of Ni and P cations. This optimized electronic configuration enhanced the kinetics of both the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Additionally, a unique particle-porous structure with abundant grain boundaries was achieved through the utilization of the Kirkendall Effect and Ostwald Ripening . In an alkaline urea electrolysis system , the alkaline urea electrolyzer assembled with ZnO–Ni 2 P/NF sample as both electrodes exhibited a low driving potential of only 1.424 V to achieve a current density of 10 mA cm −2 , which outperformed the commercial noble metal-based electrolyzer (RuO 2 ||Pt/C). The results verify that incorporating an inactive phase to manipulate the electronic structure of the active phase can be an effective strategy in developing catalysts for urea electrolysis.