High-Efficiency N<sub>2</sub> Electroreduction Enabled by Se-Vacancy-Rich WSe<sub>2-<i>x</i></sub> in Water-in-Salt Electrolytes.

Shen, Peng; Li, Xingchuan; Luo, Yaojing; Guo, Yali; Zhao, Xiaolin; Chu, Ke · ACS Nano · 2022

basic_science · Level V

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Abstract

Electrocatalytic nitrogen reduction reaction (NRR) is a promising approach for renewable NH<sub>3</sub> production, while developing the NRR electrocatalysis systems with both high activity and selectivity remains a significant challenge. Herein, we combine catalyst and electrolyte engineering to achieve a high-efficiency NRR enabled by a Se-vacancy-rich WSe<sub>2-<i>x</i></sub> catalyst in water-in-salt electrolyte (WISE). Extensive characterizations, theoretical calculations, and in situ X-ray photoelectron/Raman spectroscopy reveal that WISE ensures suppressed H<sub>2</sub> evolution, improved N<sub>2</sub> affinity on the catalyst surface, as well as an enhanced π-back-donation ability of active sites, thereby promoting both activity and selectivity for the NRR. As a result, an excellent faradaic efficiency of 62.5% and NH<sub>3</sub> yield of 181.3 μg h<sup>-1</sup> mg<sup>-1</sup> is achieved with WSe<sub>2-<i>x</i></sub> in 12 m LiClO<sub>4</sub>, which is among the highest NRR performances reported to date.