Electrochemically induced in-situ surface self-reconstruction on Ni, Fe, Zn ternary-metal hydroxides towards the oxygen-evolution performance

Self-reconstruction of oxygen evolution reaction (OER) catalyst, especially metal (oxy)hydroxides or oxides, has attracted much attention. Herein, an in-situ self-reconstruction process for Ni, Fe, Zn ternary-metal hydroxides (NFZ-TH) involving significant morphology transformation, and self-modulated electronic structure change of Ni and Fe owing to the etching of Zn species under anodic polarization potential is revealed. NFZ-TH derived materials, undergoing in-situ self-reconstruction (NFZ-TH-SR), exhibits superior OER performance (η = 217 mV @j = 10 mA cm−2geometry) and excellent stability over a period of ~48 h. Nano-pitted surface resulting from etching of Zn species improves the electrochemical surface area. Meanwhile, in NFZ-TH-SR, large amounts of defects induced defect-/corner-sited Fe and adjustability of NiOOH species are verified by Mössbauer spectra and in-situ Raman spectra respectively. Density functional theory calculations give insight that both defect-/corner- sited Fe and Ni at next-nearest-neighbour defect-site have high activity. This paper helps understand that the proposed in-situ self-reconstruction strategy can improve the electrochemical performance of OER catalysts.