Enhancing Electrocatalytic NO Reduction to NH3 by the CoS Nanosheet with Sulfur Vacancies

Electrochemical reduction of NO to NH3 is of great significance for mitigating the accumulation of nitrogen oxides and producing valuable NH3. Here, we demonstrate that the CoS nanosheet with sulfur vacancies (CoS1–x) behaves as an efficient catalyst toward electrochemical NO-to-NH3 conversion. In 0.2 M Na2SO4 electrolyte, such CoS1–x displays a large NH3 yield rate (44.67 μmol cm–2 h–1) and a high Faradaic efficiency (53.62%) at −0.4 V versus the reversible hydrogen electrode, outperforming the CoS counterpart (27.02 μmol cm–2 h–1; 36.68%). Moreover, the Zn–NO battery with CoS1–x shows excellent performance with a power density of 2.06 mW cm–2 and a large NH3 yield rate of 1492.41 μg h–1 mgcat.–1. Density functional theory was performed to obtain mechanistic insights into the NO reduction over CoS1–x.