A Transition‐Metal‐Based Bifunctional Electrocatalyst for Coupling Glucose Upgrade with Nitrate Reduction

Abstract The integration of glucose oxidation reaction (GOR) and nitrate reduction reaction (NO 3 − RR) in an electrolyzer affords a sustainable approach to produce high value‐added products and remove nitrate pollutants. Herein, a 3D hierarchical architecture consisting of defect‐rich copper–cobalt nanosheets immobilized by a cobalt phosphide‐modified nickel foam (D‐CuCo/CoP/NF) is rationally designed as a bifunctional electrocatalyst for GOR and NO 3 − RR. The resulting self‐standing electrode displayed remarkable GOR activity. Only 1.29 V vs. RHE is required to yield a current density of 100 mA cm −2 . Glucose is efficiently converted into formate with a selectivity value of 93.4% and Faraday efficiency (FE) of 90.3%. The as‐prepared D‐CuCo/CoP/NF is also capable of transforming nitrates into valuable ammonia, leading to an FE value of 96.9% and a yield rate of 802.9 µmol cm −2 h −1 . Such performance of D‐CuCo/CoP/NF renders it the best bifunctional electrocatalysts for GOR and NO 3 − RR. Mechanistic studies revealed that the defects in the catalyst greatly facilitated the adsorption of glucose and that both Cu(OH) 2 and Co 3+ ‐O/Co 4+ ‐O species served as the active sites for the reaction. A GOR||NO 3 − RR hybrid flow cell is constructed using D‐CuCo/CoP/NF as a bifunctional electrode, resulting in a current density of 100 mA cm −2 at a cell voltage of 1.35 V.