Surface-enhanced bimetallic effect of Au-Pd by internal electromagnetic fields from Au@Cu₂O for efficient electrochemical nitrate reduction to ammonia

Electrochemical synthesis of ammonia from nitrate is an attractive approach to produce high-value “zero-carbon” fuel. However, this nitrate-to-ammonia technology is still restricted by its unsatisfactory ammonia conversion, which is resulted from the inevitable by-products formed during the complicated proton-coupled electron transfer process. In this study, Au NR@Cu₂O-AuPd NPs were designed by taking advantage of the internal electromagnetic field derived from Au NR for enhanced nitrate-to-ammonia performance. The constructed Au NR@Cu₂O-AuPd NPs exhibited a high yield of ammonia (4587.00 μg h⁻¹mg_cat.⁻¹) and FE(93.09 %) in neutral solution (pH = 7), which is attributed to the different adsorption capacities of the surface bimetals for nitrate and the reaction intermediates of nitrate reduction to NH₃. Under the irradiation of light, the surface bimetals showed different responsiveness to the generated internal electromagnetic field derived from Au NR, enabling a further increase in the yield of NH₃ to 5328.99 μg h⁻¹mg_cat.⁻¹. This work provides new insights into enhancing the conversion of nitrate to NH₃ by electrocatalytic reduction through photo-modulation of the adsorption capacity on the catalyst surface.