evolution reaction

ma cm

overall water

water splitting

reaction oer

exchange membrane

density ma

overpotential mv

Nature Communications

Splitting hydrazine into H 2 and N 2 by electro-catalyzing hydrogen evolution and hydrazine oxidation reactions is promising for replacing fossil energy with H 2 . However, current hydrazine splitting is achieved using external powers to drive the two reactions, which is inapplicable to outdoor use. Here, Fe-doped CoS 2 nanosheets are developed as a bifunctional electrocatalyst for the two reactions, by which direct hydrazine fuel cells and overall-hydrazine-splitting units are realized and integrated to form a self-powered H 2 production system. Without external powers, this system employs hydrazine bifunctionally as the fuel of direct hydrazine fuel cell and the splitting target, namely a sole consumable, and exhibits an H 2 evolution rate of 9.95 mmol h −1 , a 98% Faradaic efficiency and a 20-h stability, all comparable to the best reported for self-powered water splitting. These performances are due to that Fe doping decreases the free-energy changes of H adsorption and adsorbed NH 2 NH 2 dehydrogenation on CoS 2 .

Self-powered H2 production with bifunctional hydrazine as sole consumable