Conducting Polymer-Enabled Interfacial Engineering of BiVO₄ Photoanodes for Enhanced Solar Water Splitting

Conducting polymers have emerged as promising materials for enhancing charge transport and interfacial kinetics in photoelectrochemical (PEC) energy conversion systems. In this work, we demonstrate a polymer-assisted strategy for improving the performance of BiVO₄ photoanodes through the incorporation of a polyaniline (PANI) interfacial layer and dithiooxamide-derived N,S co-doped carbon nanosheets (NSCN). The PANI layer acts as an efficient hole-transport medium, facilitating rapid charge transfer from BiVO₄ to the cobalt phosphate (CoPi) oxygen evolution catalyst, while NSCN serves as a visible-light harvester, extending light absorption and promoting photogenerated carrier generation.

The synergistic integration of NSCN and PANI significantly enhances charge separation and interfacial hole-transfer kinetics, resulting in a high-performance BiVO₄–NSCN/PANI@CoPi photoanode. Under simulated solar illumination (1 sun), the optimized photoanode delivers a stable photocurrent density of 4.46 mA cm⁻² at 1.23 V versus the reversible hydrogen electrode (V_RHE) and achieves an applied bias photon-to-current efficiency (ABPE) of 1.13% at 0.74 V_RHE. Furthermore, the photoanode exhibits remarkable operational stability, retaining 97% of its initial photocurrent after 10 h of continuous operation.

Comprehensive investigations reveal that the controlled polymeric PANI interlayer effectively bridges the semiconductor–catalyst interface, minimizes charge recombination, and accelerates hole extraction toward the oxygen evolution reaction. This study highlights the potential of conducting polymers as functional interfacial materials for developing efficient and durable photoelectrodes and provides new insights into polymer-enabled solar fuel generation technologies.