Highly selective electrochemical reduction of nitrite to ammonia over CuWO4 nanoparticles

Abstract

The electrochemical nitrite reduction reaction (NO2 -RR) represents a promising and sustainable strategy for NO2 -removal whilst simultaneously producing high-value-added ammonia (NH3). In this study, CuWO4 nanoparticles exhibited well NO2 -RR performance for NH3 production, achieving an NH3 production rate of 27.46 mg h -1 cm -2 and a Faradaic efficiency of 95.09%, while demonstrating excellent cycling stability at -1.0 V. Notably, the assembled Zn-NO2 -battery delivered a high-power density of 7.6 mW cm -2 while simultaneously yielding a substantial NH₃ production rate of 2.52 mg h -1 cm -2 . Density functional theory (DFT) calculations indicate that CuWO4 catalyzes the reaction from *NO2 to *NO2H, which constitutes the rate-determining step in NH3 synthesis.