Bifunctional Cu–Sn Oxides for Electrocatalytic Upgrade of Nitrate and Glucose to Ammonium Formate

ABSTRACT A paired electrochemical system for cathodic electrocatalytic nitrate reduction reaction (NO ₃ ^– RR) and anodic glucose oxidation reaction (GOR) offers a green approach to the sustainable production of high‐value‐added ammonium formate. Herein, bifunctional Cu–Sn oxide catalysts supported on nickel foam were synthesized via a simple one‐step soaking method for NO ₃ ^– RR and GOR. The optimized catalyst achieves a high NH ₃ yield rate of 26.57 mg h ⁻¹ cm ⁻² with a Faradaic efficiency (FE) of 85.3% at −0.4 V vs. RHE for NO ₃ ^– RR, along with excellent stability. As for GOR, a remarkable formate production rate of 44.88 mg h ⁻¹ cm ⁻² and a FE of 81.8% are achieved at 1.55 V vs. RHE. Encouraged by the outstanding performance, we constructed a NO ₃ ^– RR||GOR electrolyzer, using nitrate and glucose‐containing wastes as feedstocks, yielding 6.13 g of ammonium formate after a 4‐h electrolysis at 1.8 V. A comprehensive techno–economic analysis demonstrated that this coupled system is potentially profitable and commercially viable, with projected profits of approximately $700.50 for the co‐production of 1 tonne of ammonium formate and 5.59 tonnes of K ₂ SO ₄ . This work provides a feasible strategy to design coupling systems for the electrocatalytic valorization of renewable biomass.