Efficient tandem electroreduction of nitrate into ammonia through coupling Cu single atoms with adjacent Co3O4

Abstract

Abstract The nitrate (NO3 −) electroreduction into ammonia (NH3) represents a promising approach for sustainable NH3 synthesis. However, the variation of adsorption configurations renders great difficulties in the simultaneous optimization of binding energy for the intermediates. Though the extensively reported Cu-based electrocatalysts benefit NO3 − adsorption, one of the key issues lies in the accumulation of nitrite (NO2 −) due to its weak adsorption, resulting in the rapid deactivation of catalysts and sluggish kinetics of subsequent hydrogenation steps. Here we report a tandem electrocatalyst by combining Cu single atoms catalysts with adjacent Co3O4 nanosheets to boost the electroreduction of NO3 − to NH3. The obtained tandem catalyst exhibits a yield rate for NH3 of 114.0 mg $${}_{{{{{{\rm{NH}}}}}}_3}$$ NH 3 h−1 cm−2, which exceeds the previous values for the reported Cu-based catalysts. Mechanism investigations unveil that the combination of Co3O4 regulates the adsorption configuration of NO2 − and strengthens the binding with NO2 −, thus accelerating the electroreduction of NO3 − to NH3.