Rational Engineering on Copper‐Silver‐Ruthenium Heterostructures for the Electrocatalytic Conversion of Nitrate and Glycerol

Abstract Coupling nitrate reduction reaction (NO 3 RR) with glycerol oxidation reaction (GOR) establishes a sustainable “C─N co‐conversion” electrolysis system to generate ammonium formate. Unfortunately, the rational design of high‐performance bifunctional electrocatalysts remains challenging. Herein, we developed a 3D Ag/Ru‐decorated CuO/Cu(OH) 2 heterostructures supported by copper foams via interface engineering. The optimal catalyst exhibited outstanding NO 3 RR and GOR performance, achieving Faradaic efficiency (FE) of 97.3% and yield of 9.85 mg h −1 cm −2 at −0.5 V vs. RHE for NH 3 synthesis, and FE of 82.6% and yield of 90.31 mg h −1 cm −2 at 1.55 V vs. RHE for formate production. Mechanistic studies revealed that the decoration of Ag and Ru atoms led to electron redistribution around the copper sites, promoting proton‐coupled electron transfer and optimizing the adsorption of the reactants/intermediates. Notably, on the basis of the as‐prepared bifunctional electrode, a “NO 3 RR || GOR” electrolyzer was constructed, which achieved simultaneous output of NH 3 and formate with a current density of 100 mA cm −2 at only 1.48 V. The performance of the electrolyzer was further demonstrated using simulated nitrate pollutants and crude glycerol as feedstock, yielding 20.9 g of ammonium formate via a 4‐h electrolysis. This work demonstrates a sustainable pathway for the synthesis of high‐value‐added ammonium formate by constructing an efficient bifunctional electrocatalyst through rational interfacial engineering.