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

The nitrate (NO) electroreduction into ammonia (NH) represents a promising approach for sustainable NH 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 adsorption, one of the key issues lies in the accumulation of nitrite (NO) 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 CoO nanosheets to boost the electroreduction of NO to NH. The obtained tandem catalyst exhibits a yield rate for NH of 114.0 mg h cm, which exceeds the previous values for the reported Cu-based catalysts. Mechanism investigations unveil that the combination of CoO regulates the adsorption configuration of NO and strengthens the binding with NO, thus accelerating the electroreduction of NO to NH.