Tuning the electronic structure of W18O49 via dual doping for efficient oxygen evolution reaction

Abstract

Doping is an effective approach to tune the structure of materials at an atomic level, optimizing their performance toward various energy conversion applications. Herein, we show that nickel (Ni) and iron (Fe) dual doping activates the electrochemical inert W18O49 into a highly active electrocatalyst toward the oxygen evolution reaction (OER). Compared to monodoping, dual doping of Ni and Fe in the lattice of W18O49 results in the synergistic modulation of the electronic structure and physicochemical properties of tungsten oxides. The Ni and Fe dual-doped W18O49 (NiFe-W18O49) achieves a low overpotential of 325 mV at a current density of 10 mA cm(-2). and a Tafel slope of 42 mV deC(-1) for the OER in 0.1 M potassium hydroxide (KOH) solution, comparable with those of state-of-the-art IrO2. The Zn-air battery based on a NiFe-W18O49 cathode displays a long-term cycling durability of over 180 h, superior to the battery with a commercial Pt/C-IrO2 cathode. Combined experimental analysis and density functional theory calculations unveil that the distorted geometric structure and regulated electronic structure of W18O49 contribute crucially to the activation of its inert catalytic activity.