Triggering the water oxidation kinetics and reaction pathway via S-doping in layered hydroxides for enhanced electrocatalytic performance

Abstract

Understanding the catalytic properties and reaction kinetics to develop suitable material for OER is a major challenge. The surface morphology, conductivity, active sites, and optimum binding strength with reaction intermediates are crucial factors for choosing a suitable catalyst. In this work, we design an electrocatalyst by doping S in layered CoV hydroxide. The optimized S-doped CoV-LDH possesses high surface area, conductivity, and optimum binding strength to adsorb/desorb reaction intermediates effectively. The introduction of S in the lattice increases the electrochemical surface area and thereby increases the specific activity. The high TOF value of 1.43 s−1 at 1.6 V and 96 % Faradaic efficiency at 1.57 V potential demonstrates its good intrinsic activity and selectivity. Further, the reaction kinetics monitoring via in-situ electrochemical impedance spectroscopy and temperature-dependent study shows the requirement of less activation energy after S doping to promote OER. The mechanistic investigation via experimental and theoretical studies shows adsorbate enhancement mechanism is followed rather than lattice oxygen mechanism. The DFT study confirms that the polarizable nature of S helps to promote the last step for the facile formation of oxygen. This study showcases the in-depth understanding of reaction kinetics and mechanisms to develop a suitable electrocatalyst for OER. © 2025 Elsevier B.V.