B, N co-doped graphite carbon confined CoNiFe core-shell nanocatalyst for highly efficient oxygen evolution reaction...

Seawater splitting can effectively produce clean hydrogen as well as alleviate the problem of fresh water shortage. Herein, CoNiFe@BCN core-shell nanocatalyst is successfully prepared by a facile pyrolysis method, where the formed B, N co-doped C (BCN) shell not only protects the CoNiFe alloy from dissolving under harsh conditions, but also repels chloride ions. In addition, the synergistic effect between metal alloy and BCN shell helps to improve the catalytic activity due to the confinement effect, so that the CoNiFe@BCN only needs overpotentials of 247 and 306 mV at 10 and 100 mA cm^-2 in alkaline medium. In addition, the overpotentials of the catalyst are almost unchanged at the current densities of 10 and 100 mA cm^-2 (258 and 315 mV) in simulated seawater, demonstrating its excellent catalytic property and corrosion resistance. Moreover, the catalyst is able to achieve seawater splitting with almost 100 % Faraday efficiency, indicating its promising application for seawater electrolysis. This work provides an alternative method for preparing confined nano catalysts to produce hydrogen from seawater.