Self-powered H<sub>2</sub> production with bifunctional hydrazine as sole consumable.

Liu, Xijun; He, Jia; Zhao, Shunzheng; Liu, Yunpeng; Zhao, Zhe; Luo, Jun; Hu, Guangzhi; Sun, Xiaoming et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

Splitting hydrazine into H<sub>2</sub> and N<sub>2</sub> by electro-catalyzing hydrogen evolution and hydrazine oxidation reactions is promising for replacing fossil energy with H<sub>2</sub>. However, current hydrazine splitting is achieved using external powers to drive the two reactions, which is inapplicable to outdoor use. Here, Fe-doped CoS<sub>2</sub> 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<sub>2</sub> 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<sub>2</sub> evolution rate of 9.95 mmol h<sup>-1</sup>, 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<sub>2</sub>NH<sub>2</sub> dehydrogenation on CoS<sub>2</sub>.