Abstract
Ambient ammonia synthesis via the electrochemical reduction of nitrate (NO3-) offers us a sustainable alternative to the industrial energy-intensive Haber-Bosch process. Here, we report on the development of NiFe2O4 nanosheet arrays on carbon cloth (NiFe2O4/CC) for high-efficiency NH3 electrosynthesis via the selective reduction of NO3- under ambient conditions. When operated in 0.1 M phosphate-buffered solution with additional 0.1 M NaNO3, such NiFe2O4/CC achieves a remarkable faradaic efficiency of 96.6% and a high NH3 yield of up to 10.3 mg h(-1) cm(-2). Furthermore, it possesses excellent electrochemical and structural stability. The theoretical calculations reveal that the metallic NiFe2O4 surface has strong interactions with NO3- and can seriously inhibit the HER aiding in more efficient NO3- reduction to NH3.