Antimony-Based Composites Loaded on Phosphorus-Doped Carbon for Boosting Faradaic Efficiency of the Electrochemical Nitrogen Reduction Reaction

Abstract

A nanocomposite of PC/Sb/SbPO4 (PC, phosphorus-doped carbon) exhibits a high activity and an excellent selectivity for efficient electrocatalytic conversion of N-2 to NH3 in both acidic and neutral electrolytes under ambient conditions. At a low reductive potential of -0.15 V versus the reversible hydrogen electrode (RHE), the PC/Sb/SbPO4 catalyst achieves a high Faradaic efficiency (FE) of 31 % for ammonia production in 0.1 m HCl under mild conditions. In particular, a remarkably high FE value of 34 % is achieved at a lower reductive potential of -0.1 V (vs. RHE) in a 0.1 m Na2SO4 solution, which is better than most reported electrocatalysts towards the nitrogen reduction reaction (NRR) in neutral electrolyte under mild conditions. The change in surface species and electrocatalytic performance before and after N-2 reduction is explored by an ex situ method. PC and SbPO4 are both considered as the active species that enhanced the performance of NRR.