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

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.