Exfoliated metallic niobium disulfate nanosheets for enhanced electrochemical ammonia synthesis and Zn-N2 battery

Electrochemical nitrogen reduction reaction (NRR) under mild conditions is an attractive prospect for ammonia synthesis. However, this process faces with poor ammonia yield rate and low Faradic efficiency. Herein, we developed exfoliated metallic niobium disulfate (NbS2) nanosheets for an electrochemical NRR. Owing to more exposed active sites and high electron transfer ability, the exfoliated NbS2 nanosheets show an extraordinary activity for electrochemical NRR. A high Faradaic efficiency of 10.12 % with an ammonia yield rate of 37.58 μg h−1 mg−1cat is achieved at −0.5 V versus reversible hydrogen electrode (RHE). The Nb4+ species of exfoliated NbS2 are confirmed as active sites for NRR. When the exfoliated NbS2 nanosheets are further assembled into a Zn-N2 battery and serve as the cathode, an energy density of 714 mA h g−1 with a power density of 0.31 mW cm−2 is achieved. Notably, electrochemical NRR on exfoliated NbS2 nanosheets can be further driven by solar energy.