Efficient electron channels at the TiO2/BaTiO3 nanodot interface for enhanced CO2 photoreduction

Abstract

Unraveling electron transport channels across S-scheme heterostructures constitutes a pivotal research focus in advancing photocatalysis. Herein, an in situ growth method is used to prepare an island-shaped TiO₂/BaTiO₃ (TB) heterojunction. During the in situ growth process, the Ba²⁺ penetrates into the TiO₂ surface and constructs the BaTiO₃ phase, which produces electron channels. Due to this strategy, the photogenerated electrons of TiO₂ transfer to the valence band of BaTiO₃ via the electron transport channels, while the photogenerated electrons accumulate on the conduction band of BaTiO₃ to reduce CO₂. Owing to the efficient electron transport channel at the BaTiO₃ nanodot interfaces, the performance of the optimized TB sample is greatly improved to 45.4 µmol g⁻¹ h⁻¹ for CO₂-to-CO and 173.3 µmol g⁻¹ h⁻¹ for CO₂-to-CH₄ conversion, with a 93.9% CH₄ electron selectivity. Characterization and theoretical calculations show that the interface constructs an electron transport channel and accelerates the transfer of photogenerated electrons. This work proposes an in situ strategy to construct island-type S-scheme interfaces with directional charge-transfer channels, enabling efficient photocatalytic performance.