Wavelength-dependent switching of photocatalytic reaction pathways on BiVO₄ under visible light irradiation

Hot charge carriers generated under high-energy photoexcitation have attracted significant attention due to their potential to drive photocatalytic reactions beyond conventional thermodynamic limits. However, their direct utilization in semiconductor photocatalysis and their influence on reaction pathways remain insufficiently understood. This work suggests that energetic electrons generated under higher-energy excitation contribute to distinct photocatalytic pathways on BiVO₄ under visible light irradiation. The decolorization of methylene blue (MB) under blue and green light irradiation reveals distinct reaction pathways. Under green light, a pronounced blue shift of the MB absorption peak indicates hole-mediated stepwise demethylation, whereas under blue light, rapid decolorization with minimal spectral shift suggests a dominant electron-driven pathway. Control experiments under matched photon flux and scavenger studies confirm that the distinct spectral evolution originates from the excitation wavelength rather than photon flux. Furthermore, efficient photo-deposition of Au occurs only under blue light irradiation, suggesting that energetic electrons generated under higher-energy excitation may participate in surface reduction reactions before thermal relaxation. These findings suggest that energetic electrons generated under higher-energy excitation contribute to wavelength-dependent photocatalytic pathways.