A Polyaniline Derivative Interlayer Mediated Z-Scheme BiVO ₄ /MoO ₃ Heterostructure for Enhanced Photoelectrochemical Water Oxidation

A BiVO 4 /polyaniline derivative interlayer mediated Z-Scheme BiVO 4 /MoO 3 (BPM) heterostructure photoanode is rationally designed and fabricated for enhanced photoelectrochemical (PEC) water oxidation. The polyaniline derivative interlayer, formed via annealing polyaniline at 500 °C under Ar, serves as an efficient charge-transfer mediator. Selective Au photodeposition experiments provide direct evidence for the Z-scheme charge transfer pathway, preserving the strong reducibility of BiVO 4 conduction band electrons. The optimized BPM photoanode delivers a photocurrent density of 0.92 mA cm –2 at 1.23 V vs RHE, which is further boosted to 2.13 mA cm –2 after Co-Pi cocatalyst modification, 3.9 times higher than that of pristine BiVO 4 . Frequency-dependent Mott–Schottky analysis confirms a significantly enhanced effective carrier density and negatively shifted flat-band potential. Moreover, the BPM/Co-Pi photoanode exhibits good stability with ∼85% photocurrent retention after 10 h continuous operation. This work presents a strategy utilizing conductive polymer-derived carbon-rich interlayers to mediate Z-scheme charge transfer, offering a promising route to design high-performance photoanodes for solar fuel production.