Density Functional Theory Approximations and Experimental Investigations on Co1-xMoxTe2 Alloy Electrocatalysts Tuning the Overall Water Splitting Reactions

Abstract

Understanding the relationship between electronic structure,surfacecharacteristic, and reaction process of a catalyst helps to architectproficient electrodes for sustainable energy development. The highlyactive and stable catalysts made of earth-abundant materials providea great endeavor toward green hydrogen production. Herein, we assembledthe Co1-x Mo x Te (x = 0-1) nanoarray structures intoa bifunctional electrocatalyst to achieve high-performance hydrogenevolution reaction (HER) and oxygen evolution reaction (OER) kineticsunder alkaline conditions. The designed Co0.75Mo0.25Te and Co0.50Mo0.50 electrocatalysts requireminimum overpotential and Tafel slope for high-efficacy HER and OER,respectively. Furthermore, we constructed a Co0.50Mo0.50Te2 parallel to Co0.50Mo0.50Te2 device for overall water splitting with an overpotentialof 1.39 V to achieve a current density of 10 mA cm(-2), which is superior to noble electrocatalyst performance, with stablereaction throughout the 50 h continuous process. Density functionaltheory approximations and Gibbs free energy calculations validatethe enhanced water splitting reaction catalyzed by the Co0.50Mo0.50Te2 nanoarrays. The partial replacementof Co atoms with Mo atoms in the Co0.50Mo0.50Te2 structure substantially enhances the water electrolysiskinetics through the synergistic effects between the combined metalatoms and the bonded chalcogen.