Boosted nitrate electroreduction to ammonia on Fe-doped SnS 2 nanosheet arrays rich in S-vacancies.

The electrochemical nitrate reduction reaction (NO 3 RR) not only holds great potential for the removal of NO 3 - contaminants from the environment, but also potentially provides a renewable-energy-driven NH 3 synthesis method to replace the Haber-Bosch process. Herein, we report that Fe-doped SnS 2 nanosheets enriched with S-vacancies can be used as an efficient NO 3 RR catalyst, showing a high NH 3 yield of 7.2 mg h -1 cm -2 (at -0.8 V) and a faradaic efficiency of 85.6% (at -0.7 V). Density functional theory (DFT) calculations revealed that S-vacancies on Fe-SnS 2 serve as the main active sites for the NO 3 RR and the Fe-doping can further regulate the electronic structure of S-vacancies to optimize the binding energies of NO 3 RR intermediates, resulting in reduced energy barriers and enhanced NO 3 RR activity.