Synergetic effect of both cation and anion doping cobalt oxides on V2C MXene boosting oxygen evolution reaction

Abstract

In order to enhance the conductivity and catalytic efficiency of non-noble electrocatalyst, an electrocatalysts consisting of ZnCo metallic double oxide with S doping embedded on V2C MXene for oxygen evolution reaction (OER) is synthesized. Cobalt serves as the primary active site, while zinc contributes to improve conductivity owing to its high electronegativity. Sulfur doping plays a crucial role in reducing the energy barrier of rate determining step of OER. The V2C MXene as a substrate can promote conductivity as well, resulting in synergistic effect. The electrocatalyst exhibits a low overpotential of 240 mV at 10 mA cm−2 in alkaline electrolyte, surpassing that of IrO2 commercial electrocatalyst. The potential shows only a minimal ∼5 mV day after 72-h stability test at 20 mA cm−2. The current density at 1.6 V vs RHE is 2 times that of commercial IrO2. Both theoretical calculation and experimental result demonstrate the advantage brought by the incorporation of zinc and sulfur. This work introduces a new idea of synergetic effect in non-noble metallic electrocatalysis.