Semi-coherent Interface and Vacancy Engineering for Constructing NiTe/FeTe/Fe3O4/FF to Boost Electrochemical Overall Water Splitting.

Abstract

Transition metal-based tellurides (TMTs) with excellent electrical conductivity are expected to be ideal electrocatalysts for overall water splitting. However, compared to transition metal sulfides and selenides, the reported applications of TMTs in overall water splitting are fewer. Herein, the NiTe/FeTe/Fe3O4/FF carnation flower-like with a semi-coherent interface is successfully constructed to enhance the electrochemical overall water splitting performance. Specifically, it achieves low overpotentials of 54 and 176 mV at 10 mA cm-2 forthe hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. What's more, the electrolyzer requires a cell voltage of 1.5 V to sustain a current density of 10 mA cm-2 and maintains remarkable stability for an extensive duration of 450 h even at a current density of 100 mA cm-2. Semi-coherent interface engineering and vacancy engineering not only improve the OH⁻ adsorption capacity of catalysts but also promote the desorption of adsorbed hydrogen (Hads). In situ Raman spectroscopy reveals that FeOOH and NiOOH formed by NiTe/FeTe/Fe3O4/FF during the OER are the genuine active sites. This study provides a promising approach for the electrochemical water splitting of TMTs by combining semi-coherent interface engineering and vacancy engineering.