Efficient ammonia electrosynthesis by coupling to concurrent methanol oxidation

Abstract

The electrosynthesis of ammonia by nitrogen reduction reaction is one of the most attractive research fields; however, it suffers from both extremely low NH3 yield, poor faradic efficiency and the sluggish kinetics of anodic oxygen evolution reaction. Herein, a novel nitrogen-methanol co-electrolysis system has been established to reduce the overall energy consumption and produce value-added formate at anode by employing anodic methanol oxidation reaction substituting for oxygen evolution reaction, for which noble-metal-free Bi-based electrode catalysts were designed and used. Significantly, the Bi/Bi2O2CO3 nanosheets exhibits a rather high NH3 yield of 3.18 ± 0.26 μg h−1 cm−2 and a faradic efficiency of 14.59% ± 1.41% at −1.3 V (vs. Ag/AgCl). Excitingly, the overall required potential of established nitrogen reduction reaction electrolyzer is decreased by 251 mV at 10 mA cm−2 of the novel designed nitrogen-methanol co-electrolysis system compared with traditional nitrogen-water co-electrolysis, manifesting much decreased energy consumption of the coupled system.