Carbon Layer-Promoted Carrier Separation of BiVO4 at the Gas−Solid Interface for Solar-Driven Water Oxidation

Abstract Water oxidation constitutes the persistent rate-determining bottleneck in overall photocatalytic water splitting. To break this barrier, incorporating a carbonaceous intermediate layer can drastically boost charge separation, while a localized thermal field accelerates carrier migration kinetics. Herein, a bismuth vanadate (BiVO4)/carbon composite photocatalyst was fabricated and immobilized onto a carbonized foam skeleton, successfully constructing a distinctive gas−solid interface for solar-driven photothermal catalytic water oxidation. Under AM 1.5 G irradiation, the polydopamine (PDA)-derived carbon-modified system exhibits exceptional oxygen evolution performance, delivering a remarkable ∼15-fold performance enhancement compared to its pristine counterpart. Comprehensive electrochemical and photoluminescence investigations substantiate that the interfacial carbon layer not only establishes an accelerated transport pathway for rapid charge separation but also acts as a robust photothermal receptor. This dual-functionality induces substantial thermal localization at the reaction sites, thereby driving the reaction kinetics. Overall, this work provides a versatile paradigm for interface and thermal engineering in semiconductors, paving a promising avenue for high-efficiency solar-to-chemical energy conversion. The key point is that this material is cost-effective and, combined with the scalable carbonization preparation process, makes this gas−solid photocatalytic structure a promising candidate solution for large-scale solar-driven water treatment and clean fuel production.