Boosted Photothermal Catalytic Hydrogen Evolution in TiO2/Bi2Te3 Systems via Controlled Transformation of Bi–Te Phonon-Glass to Bi–Te–O Glass

Photothermal catalysis has shown great promise for efficient water splitting toward green hydrogen production for its unique capability to convert sunlight into energetic hot carriers and localized thermal energy. However, suitable catalyst systems that fully exploit these effects remain limited. Phonon glass materials such as Bi₂Te₃offer a broad spectrum of light absorption, making them attractive photothermal promoters, yet they contribute minimally to hot carrier generation. In this study, we explored the transformation of Bi₂Te₃into Bi–Te–O glass phases and leveraged their photothermal/excitonic synergy, where thermal energy accelerates surface kinetics and excitonic species supply reactive charge carriers, by integrating them with TiO₂to promote photothermal catalytic performance. Engineering thermal treatment at varying temperatures, we developed a TiO₂/Bi₂Te₃/Bi₂Te₄O₁₁composite that achieved an optimized balance between photothermal and excitonic properties. Structural, optical, and surface analyses reveal that this balance is critical to achieving a hydrogen evolution rate of 2572 μmol h^–1g^–1, nearly 10-fold higher than that of pristine TiO₂(268 μmol h^–1g^–1). These findings demonstrate a novel phase-engineering strategy for Bi₂Te₃-based hybrids, offering a dual approach via thermal and electronic pathways to guide the rational design of next-generation photothermal catalysts for solar fuel production.