Promotion of the oxygen evolution performance of Ni–Fe layered hydroxides via the introduction of a proton-transfer mediator anion

Developing efficient catalysts with high durability and activity for the oxygen evolution reaction(OER)is imperative for sustainable energy conversion technologies,including hydrogen generation and CO_(2) reduction,as well as other electrochemical energy storage systems.To this end,a comprehensive understanding of the mechanism for the water oxidation reaction is vital.Herein,a surfactant,nonafluoro-1-butanesulfonate(FBS),was introduced into Ni-Fe layered double hydroxide(Ni Fe-FBS/CFP)via electrochemical deposition on the surface of a carbon fiber paper(CFP)substrate.The as-prepared Ni Fe-FBS/CFP electrode exhibited excellent catalytic activities for OER compared to the Ni-Fe layered double hydroxide based electrode(Ni Fe-LDH/CFP),an excellent stability of 15 h,and an ultralow Tafel slope of 25.8 m V dec-1.Furthermore,by combining the results of p H-dependent kinetics investigations,chemical probing,proton inventory studies,and isotopic and atom-protontransfer measurements,it was observed that a proton-transfer process controls the reaction rates of both the Ni Fe-LDH and Ni Fe-FBS catalysts,and the residual sulfonate groups serve as proton transfer mediator to accelerate the proton transfer rate.