Phase-Preserving Defect Engineering of TiO2(B) Nanosheets Enables Vacancy-Anchored Metallic Cu for Photocatalytic H2 Evolution

Mild calcination preserves porous TiO 2 (B) nanosheets and tunes oxygen vacancies • Oxygen vacancies stabilize highly dispersed metallic Cu on TiO 2 (B) • Cu-Vo interfaces promote electron transfer and suppress charge recombination • Cu-TiO 2 (B)-200 reaches 7.92   mmol   g -1 h -1 under AM 1.5 simulated sunlight TiO 2 (B) is a promising photocatalyst for solar-driven H 2 evolution, yet its performance is limited by rapid charge recombination and insufficient surface reduction sites. Herein, a vacancy-assisted strategy combining mild thermal treatment with in situ photodeposition is developed to construct highly dispersed metallic Cu species on TiO 2 (B) nanosheets. Calcination at 200 °C preserves the metastable TiO 2 (B) framework while generating an appropriate concentration of surface oxygen vacancies, which serve as preferential anchoring sites for Cu and promote strong electronic coupling at the Cu-TiO 2 (B) interface. Under air mass 1.5 simulated sunlight with methanol as a sacrificial agent, the optimized Cu-loaded TiO 2 (B) sample treated at 200 °C achieves an H 2 evolution rate of 7.92   mmol   g -1 h -1 and retains stable activity over five consecutive cycles. Comprehensive structural and spectroscopic characterizations, together with first-principles calculations, demonstrate that oxygen-vacancy-mediated Cu anchoring strengthens metal-support electronic coupling, promotes directional charge transfer and carrier separation, and facilitates interfacial proton reduction. These results establish a mechanistic correlation among phase preservation, oxygen-vacancy regulation, Cu dispersion, and photocatalytic performance. This work provides a practical and cost-effective strategy for constructing efficient non-noble-metal interfaces on metastable oxide photocatalysts. Download: Download high-res image (204KB) Download: Download full-size image A mild defect-engineering strategy preserves the TiO 2 (B) framework while generating oxygen vacancies that stabilize highly dispersed metallic Cu species. The resulting Cu-Vo interfaces promote directional electron transfer, suppress charge recombination, and facilitate interfacial proton reduction, thereby enhancing photocatalytic H 2 evolution under AM 1.5 simulated sunlight.