Porous Cu nanosheets for efficient ammonia production via nitrate electroreduction

Abstract

The electrochemical nitrate reduction reaction (NO₃RR) offers a promising alternative synthetic route for sustainable ammonia (NH₃) production, effectively removing nitrate (NO₃⁻) from wastewater under mild operating conditions. Copper (Cu) nanomaterials are considered to be effective catalysts for the NO₃RR. This study reports the simple synthesis of porous Cu nanosheets via a two-step reaction, which are obtained from the electrochemical reduction of CuO nanosheets. The porous Cu nanosheets exhibit a high selectivity and activity for the NO₃RR, achieving an NH₃ yield of 42.5 mg h⁻¹ mg_cat⁻¹ and a faradaic efficiency of 97.0% for the conversion of NO₃⁻ to NH₃ at the potential of −0.7 V (vs. RHE). The prominent electrocatalytic activity can be ascribed to the porous architecture, high surface area, and low mass transfer resistance.