Efficient Electrochemical Ammonia Synthesis from Nitric Oxide Using Highly Dispersed Cu3P Nanoclusters Anchored on N-Doped Carbon Nanorods

Abstract

The electrochemical synthesis of green ammonia from NO has attracted great attention as an alternative strategy for the Haber-Bosch process. However, nitric oxide reduction reaction (NORR) has bottlenecks such as low selectivity toward NH3 and poor stability of catalysts under corrosive reaction environment for efficient NH3 production. Herein, highly dispersed copper phosphide nanocluster embedded in nitrogen-doped carbon nanorod (Cu3P/NCNR) electrocatalysts are obtained by the simple electrospinning technique and calcination process. The Cu3P/NCNR-2 synthesized at 800 °C achieved the highest Faradaic efficiency (FENH3) of 78.7 ± 0.7% with NH3 yield rate of 26.4 ± 0.6 µmol cm−2 h−1 at −0.3 V (vs. RHE) in 0.1 м HCl electrolyte. The control experiments indicated that the Cu3P is the active center in Cu3P/NCNR-2. The synergistic effect of the highly dispersed Cu3P nanoclusters on the N-doped carbon and the optimal Cu/P ratio enhanced NORR performance of Cu3P/NCNR-2. The cycle stability and 24 h long-term durability test are carried out to verify the robustness of Cu3P/NCNR-2 electrocatalyst. Furthermore, the Cu3P/NCNR-2 catalyst is introduced as the cathode in the Zn-NO battery, which delivered a high-power density of 3.3 mW cm−2 at a high current density of 2.5 mA cm−2 while simultaneously producing an NH3 yield of 250.9 µg cm−2 h−1 during the galvanostatic discharge.