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

Abstract The nitrate (NO 3 − ) electroreduction into ammonia (NH 3 ) represents a promising approach for sustainable NH 3 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 NO 3 − adsorption, one of the key issues lies in the accumulation of nitrite (NO 2 − ) 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 Co 3 O 4 nanosheets to boost the electroreduction of NO 3 − to NH 3 . The obtained tandem catalyst exhibits a yield rate for NH 3 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 Co 3 O 4 regulates the adsorption configuration of NO 2 − and strengthens the binding with NO 2 − , thus accelerating the electroreduction of NO 3 − to NH 3 .