Improving the Catalytic Efficiency of NiFe-LDH/ATO by Air Plasma Treatment for Oxygen Evolution Reaction

Developing efficient catalysts toward the oxygen evolution reaction(OER) is important for water splitting and rechargeable metal-air batteries. Although NiFe oxides are considered as potentially applicable catalysts in the alkaline media, there are still a limited numbers of researches working on membrane electrode assembly(MEA) fed with pure water due to their poor electrical conductivity. In this work, antimony doped tin oxide(ATO) has been employed as conductive supports where NiFe layered double hydroxide uniformly dispersed[named NiFe-LDH(layered double hydroxide)/ATO]. The catalysts have been synthesized by a one-step co-precipitation method, and then NiFe-LDH/ATO-air plasma was obtained through mild air plasma treatment. According to XPS analysis, binding energies of Ni2p and Fe2p were shifted negatively. Moreover, a new signal of low oxygen coordination appeared on O1s spectrum after air plasma treatment. These XPS results indicated that oxygen vacancies(Ov) were generated after air plasma treatment. Electrochemical measurement indicated that the vacancy-rich NiFe-LDH/ATO-air plasma exhibited better performance than NiFe-LDH/ATO not only in 1 mol/L KOH solutions but also in an alkaline polymer electrolyte water electrolyzer(APEWE) fed with deionized water. This work provides a feasible way to design practical catalysts used in electrochemical energy conversion systems by choosing corrosion resistance supports and defect engineering.