Improved Solar‐Powered Water‐Splitting Performance of Bi ₄ Ti ₃ O ₁₂ /TiO ₂ Composite with Synergistically Interacted Heterointerfaces Under Platinum Cocatalysis

Abstract Perovskite‐phase Bi ₄ Ti ₃ O ₁₂ (BTO) is recognized as a potential candidate for solar‐powered water‐splitting due to its special conduction‐band and valence‐band positions. However, due to its broadband defect and surface chemical inertness, it is difficult to obtain outstanding water‐splitting performance under photoirradiation. Herein, a donor‐acceptor system with synergistically interacted heterointerface is constructed by growing TiO ₂ nanoparticles on BTO microspheres, and an internal high‐speed electron transfer channel is established to improve the photoelectric property under the electronic interaction of surface Pt nanocatalyst. Due to the excellent broadband‐light harvesting capacity, significantly accelerated photoexciton separation/transfer, and introduction of abundant active sites, it effectively hindered the photoexciton recombination, thereby ≈3093.16 µmol·g ⁻¹ ·h ⁻¹ of H ₂ O‐to‐H ₂ rate (pH = 11) and 673.85 µmol·g ⁻¹ ·h ⁻¹ of H ₂ O‐to‐O ₂ rate (pH = 4) are achieved under simulated sunlight irradiation, reaching ≈0.1062% of solar‐to‐exciton utilization efficiency, which obviously outperformed the majority of recently reported photocatalysts. After a process of PVDF‐networked membrane, a stable water‐splitting activity is maintained during 10 cycles (50 h) due to the reinforced organic–inorganic interface and convenient separation/recovery property. This study proposes a valuable strategy for improving the water‐splitting performance of BTO‐based photocatalyst.