Electrical-Driven Directed-Evolution of Copper Nanowires Catalysts for Efficient Nitrate Reduction to Ammonia

The electrocatalytic conversion of nitrate (NO₃ ^-) to NH₃ (NO₃RR) at ambient conditions offers a promising alternative to the Haber-Bosch process. The pivotal factors in optimizing the proficient conversion of NO₃ ^- into NH₃ include enhancing the adsorption capabilities of the intermediates on the catalyst surface and expediting the hydrogenation steps. Herein, the Cu/Cu₂O/Pi NWs catalyst is designed based on the directed-evolution strategy to achieve an efficient reduction of NO₃‾. Benefiting from the synergistic effect of the O_V-enriched Cu₂O phase developed during the directed-evolution process and the pristine Cu phase, the catalyst exhibits improved adsorption performance for diverse NO₃RR intermediates. Additionally, the phosphate group anchored on the catalyst's surface during the directed-evolution process facilitates water electrolysis, thereby generating H_ads on the catalyst surface and promoting the hydrogenation step of NO₃RR. As a result, the Cu/Cu₂O/Pi NWs catalyst shows an excellent FE for NH₃ (96.6%) and super-high NH₃ yield rate of 1.2 mol h^-1 g_cat. ^-1 in 1 m KOH and 0.1 m KNO₃ solution at -0.5 V versus RHE. Moreover, the catalyst's stability is enhanced by the stabilizing influence of the phosphate group on the Cu₂O phase. This work highlights the promise of a directed-evolution approach in designing catalysts for NO₃RR.