Development of stratified 2D titanate nanosheets-tungsten oxide heterolayered thin films for effective photocatalytic degradation of tetracycline hydrochloride

Abstract

Developing visible-light-active photocatalysts with enhanced photocatalytic properties is essential to use the solar spectrum effectively. Heterolayered photocatalyst thin films of stratified TiO₂-WO₃ are developed by sequential depositions of titanate nanosheets (titanate-NS) and tungsten oxide (WO₃). The electrophoretic deposition method is used for the deposition of exfoliated titanate-NS, and modified chemical solution deposition (MCSD) is used for the deposition of WO₃. The TiO₂-WO₃ heterolayered thin films displayed randomly interconnected WO₃ nanoplate network grown on parallelly stratified titanate-NS. The TiO₂-WO₃ heterolayered thin films display high visible-light absorption with quenched photoluminescence signal, characteristic of visible-light harvesting capability with effective electronic coupling between titanate-NS and WO₃. The TiO₂-WO₃ heterolayered thin films show superior visible-light-driven photocatalytic degradation of tetracycline hydrochloride (TC) antibiotic. The resultant heterolayered thin films photodegrade 86 % of TC in 150 min. These photocatalytic performances surpass the bare WO₃ films under the same conditions. This finding demonstrates that the TiO₂-WO₃ heterolayered thin films are efficient visible-light-active photocatalysts for the degradation of antibiotics. This study clearly demonstrates that 2D exfoliated titanate nanosheets can be used as macromolecules to build a stratified nanosheet thin film platform that is beneficial for developing intimately coupled semiconductor thin films.