Defective CuO-rich CuFe2O4 nanofibers enable the efficient synergistic electrochemical reduction of nitrate to ammonia

CuO-rich CuFe 2 O 4 nanofibers with oxygen vacancies as a NO 3 − RR catalyst achieve a high Faradaic efficiency of 91.08% and a large NH 3 yield of 9296.21 μg h −1 cm −2 at −1.0 V vs. RHE in 0.1 M PBS with 0.1 M NO 3 − .