Interfacial Charge Transport Engineering in MoO3 via Integration of PEDOT:PSS for Efficient and Durable Oxygen Evolution Reaction

Electrochemical water oxidation is a grave half-reaction in overall water splitting. However, its practical efficiency is largely restricted by sluggish oxygen evolution reaction (OER) kinetics and the poor electrical conductivity of many transition-metal oxide catalysts. Herein, we report a rationally engineered molybdenum oxide-poly(3,4-ethylenedioxythiophene) (MoO3-PEDOT:PSS) hybrid electrocatalyst designed to enhance interfacial charge transport and accelerate alkaline OER kinetics. The MoO3 framework was first grown on carbon cloth through a hydrothermal route, accompanied by PEDOT:PSS surface modification using a simple immersion strategy. The conformal deposition of PEDOT:PSS onto molybdenum oxide nanostructures establishes a highly conductive and electronically coupled interface that significantly accelerates charge transport and optimizes adsorption energetics of reaction intermediates. Benefiting from the optimized integration of conductive PEDOT:PSS with the MoO3 framework, the MoO3-PEDOT:PSS-2 electrode delivers enhanced OER activity with a low overpotential of 302.4 mV at 10 mA cm−2, a Tafel slope of 65.9 mV dec−1, and stable performance after 5000 CV cycles and 30 h chronopotentiometry. In particular, the PEDOT:PSS layer not only facilitates efficient electron transport but also stabilizes the reconstructed active phases during prolonged operation, thereby suppressing performance degradation. This work highlights the critical role of polymer-assisted interfacial electronic modulation in transition metal oxides and provides a versatile strategy for designing next-generation, binder-free electrocatalysts for effectual and durable water oxidation.