Capturing Copper Single Atom in Proton Donor Stimulated O‐End Nitrate Reduction

Abstract Ammonia (NH₃) is vital in global production and energy cycles. Electrocatalytic nitrate reduction (e‐NO₃RR) offers a promising route for nitrogen (N) conversion and NH₃ synthesis, yet it faces challenges like competing reactions and low catalyst activity. This study proposes a synergistic mechanism incorporating a proton donor to mediate O‐end e‐NO₃RR, addressing these limitations. A novel method combining ultraviolet radiation reduction, confined synthesis, and microwave treatment was developed to create a model catalyst embedding Cu single atoms on La‐based nanoparticles (p‐CNCu^sLaⁿ‐m). DFT analysis emphasizes the critical role of La‐based clusters as proton donors in e‐NO₃RR, while in situ characterization reveals an O‐end adsorption reduction mechanism. The catalyst achieves a remarkable Faraday efficiency (FE_NH3) of 97.7%, producing 10.6 mol g_metal⁻¹ h⁻¹ of NH₃, surpassing most prior studies. In a flow cell, it demonstrated exceptional stability, with only a 9% decrease in current density after 111 hours and a NH₃ production rate of 1.57 mg_NH3/h/cm⁻². The proton donor mechanism's effectiveness highlights its potential for advancing electrocatalyst design. Beyond NH₃ production, the O‐end mechanism opens avenues for exploring molecular‐oriented coupling reactions in e‐NO₃RR, paving the way for innovative electrochemical synthesis applications.