Boosting electrocatalytic ammonia synthesis from nitrate by asymmetric chemical potential activated interfacial electric fields

The electrocatalytic nitrate reduction reaction (NO₃⁻ RR) has immense potential to alleviate the problem of groundwater pollution and may also become a key route for the environmentally benign production of ammonia (NH₃) products. Here, the unique effects of interfacial electric fields arising from asymmetric chemical potentials and local defects were integrated into the binary Bi₂S₃-Bi₂O₃ sublattices for enhancing electrocatalytic nitrate reduction reactions. The obtained binary system showed a superior Faraday efficiency (FE) for ammonia production of 94 % and an NH₃ yield rate of 89.83 mg g_cat^-1h⁻¹ at −0.4 V vs. RHE. Systematic experimental and computational results confirmed that the concerted interplay between interfacial electric fields and local defects not only promoted the accumulation and adsorption of NO₃^–, but also contributed to the destabilization of *NO and the subsequent deoxygenation hydrogenation reaction. This work will stimulate future designs of heterostructured catalysts for efficient electrocatalytic nitrate reduction reactions.