Electrocatalytic nitrite reduction to ammonia on In1Cu single atom alloy

[Display omitted] •Indium-copper single-atom alloy (In1Cu) is explored as an efficient NO2RR catalyst.•In1Cu achieves an NH3 yield rate of 1042.1 μmol h−1 cm−2 and FENH3 of 94.7 % at 354 mA cm−2.•In1-Cu dinuclear sites enhance the NO2− activation and optimize the reaction energetics of NHO pathway.•This work demonstrates the great potential of In1Cu for practical ammonia electrosynthesis via NO2RR. Electrochemical NO2− reduction to NH3 (NO2RR) holds significant potential for simultaneously mitigating NO2− pollutants and producing valuable NH3. Herein, we design single-atom In1 alloyed Cu (In1Cu) as an effective and long-lasting catalyst for the NO2RR. Through a combination of experimental and theoretical investigations, we discover that the enhanced NO2RR performance of In1Cu arises from its surface In1-Cu dinuclear sites to promote the NO2− activation, optimize the reaction energetics of NHO pathway and suppress the competing hydrogen evolution. As a result, In1Cu integrated into the flow cell achieves the outstanding NH3-Faradaic efficiency of 94.7 % and NH3 yield rate of 1042.1 μmol h−1 cm−2 at a high current density of 354 mA cm−2, placing it among the most effective NO2RR catalyst ever reported.