Plasmon-Driven Reaction Selectivity Tuning for Photoelectrochemical H2O2 Production

Photoelectrochemical (PEC) H2O2 production has gained interest as a green, promising route to produce valuable chemicals. However, it suffers from low H2O2 Faradaic efficiency due to competing O2 generation. Here, we propose a plasmon-driven band structure engineering strategy to thermodynamically regulate the product selectivity of a metal oxide based PEC photoanode. It is demonstrated that the plasmonic near-field generated by the periodically patterned Au nanosphere arrays (Au-PAT) effectively modulates the surface photovoltage and energy band structure of the BiVO4 photoanode. This modulation helps photoinduced charge carriers to satisfy the thermodynamic potential required to shift the water oxidation reaction (WOR) product from O2 to high-value H2O2. As a result, BiVO4/Au-PAT achieves a H2O2 Faradaic efficiency approximately 3.3 times higher than that of pristine BiVO4. These findings suggest the effectiveness of external modulation, originating from a plasmonic near-field effect, in regulating the WOR pathway, providing an efficient and selective route to value-added PEC production.