Interface engineering of amorphous/crystalline heterojunctions with synergistic Ru doping for efficient hydrazine oxidation assisted overall water splitting

Abstract

Developing highly active electrocatalysts for overall water splitting is critical for the extensive implementation of renewable hydrogen. In this work, interface engineering is adopted to synthesize an electrocatalyst (Ru–VO_x/Ni₃S₂) with an amorphous/crystalline heterostructure, and the hydrazine oxidation reaction (HzOR) with a lower theoretical potential was employed to overcome the sluggishness of the oxygen evolution reaction (OER). The resultant electrocatalyst not only demonstrates splendid HER activity (7 mV@10 mA cm⁻²), OER activity (215 mV@10 mA cm⁻²), HzOR activity (−66 mV@10 mA cm⁻²), and electrolyzer activity (0.015 V@10 mA cm⁻² for overall water splitting assisted by hydrazine oxidation) but also exhibits favorable stability upon being used in the hydrazine-aided water splitting. Experimental results and DFT calculations indicate that the formation of a heterojunction and incorporation of Ru can synergistically improve charge transfer across the interface, resulting in exceptional performance in the HER, OER, and HzOR. This work provides a highly efficient strategy for the development of multifunctional catalysts utilized in the green hydrogen industry.