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

A novel exfoliated NbS2 nanosheets produced via liquid exfoliation method exhibited an excellent catalytic activity for nitrogen reduction reaction. [Display omitted] •A novel exfoliated NbS2 nanosheets was produced via liquid exfoliation method.•Exfoliated NbS2 nanosheets exhibited an excellent catalytic activity for NRR.•The Nb4+ species of exfoliated NbS2 nanosheets was acted as active sites.•Exfoliated NbS2 nanosheets was acted as the cathode for a Zn-N2 battery.•Solar-driven NRR-OER device was achieved with exfoliated NbS2 nanosheets. 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.