Modulating Hydrogen Species for Efficient and Sustainable Nitrate Electroreduction to Ammonia

The electrochemical nitrate reduction reaction (NO₃RR) represents a promising strategy for sustainable NH₃ synthesis and environmental remediation. However, developing an NH₃ production process that achieves both high current density and Faradaic efficiency (FE) is challenging owing to the strong electrostatic repulsion of NO₃ ^- from the electrode surface and the competing hydrogen evolution reaction at high current densities. Here, Cu/C electrode, modified using 1-dodecanol (C₁₂OH), achieves an exceptional NH₃ yield rate of 4.50 mmol cm^-2 h^-1 and FE_NH3 of 98.9% at 1.0 A cm^-2. This performance significantly surpasses that of the pristine Cu/C catalyst and most reported state-of-the-art catalysts. C₁₂OH modification, which induces the reconstruction of the hydrogen-bonded network on the electrode surface, not only enhances NO₃ ^- enrichment but also promotes H^• radical generation. This new pathway, mediated by H^• radicals, is both thermodynamically and kinetically favorable and underlies the promoted NH₃ production.