BN Pairs Enriched Defective Carbon Nanosheets for Ammonia Synthesis with High Efficiency.

Abstract

Electrochemical synthesis has garnered attention as a promising alternative to the traditional Haber-Bosch process to enable the generation of ammonia (NH3 ) under ambient conditions. Current electrocatalysts for the nitrogen reduction reaction (NRR) to produce NH3 are comprised of noble metals or transitional metals. Here, an efficient metal-free catalyst (BCN) is demonstrated without precious component and can be easily fabricated by pyrolysis of organic precursor. Both theoretical calculations and experiments confirm that the doped BN pairs are the active triggers and the edge carbon atoms near to BN pairs are the active sites toward the NRR. This doping strategy can provide sufficient active sites while retarding the competing hydrogen evolution reaction (HER) process; thus, NRR with high NH3 formation rate (7.75 µg h-1 mgcat. -1 ) and excellent Faradaic efficiency (13.79%) are achieved at -0.3 V versus reversible hydrogen electrode (RHE), exceeding the performance of most of the metallic catalysts.