Coupling of ruthenium with hybrid metal nitrides heterostructure as bifunctional electrocatalyst for water electrolysis.

Noble metal-based materials are the benchmark catalysts for electrocatalysis, but their wide applications are hindered due to their scarcity and high cost. Developing a feasible strategy to achieve higher catalytic activity with low usage of noble metals is vital and urgent. Herein, a simple nitridation route is proposed to design a hybrid material with both ruthenium (Ru) species and mixed metal nitride matrixes (Ru-NiWN). Benefitting from the intrinsic high conductivity of metal nitrides, abundant catalytic active sites, and strong electron interactions, the Ru-NiWN catalyst shows excellent bifunctional activity in alkaline electrolytes. The overpotentials are 70 mV and 270 mV at the geometric current density of 100 mA cm for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. After further assembly into an electrolyzer, the Ru-NiWN also shows superior performance. The voltage of the electrolyzer only needs 1.49 V to reach 100 mA cm at the test temperature of 80 °C, indicating the promising application for hydrogen production. Our work paves a new strategy to design high-active hybrid materials for overall water splitting.