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

Abstract

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−1mgcat.−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−1mgcat.−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.