In-Situ Constructing Eosin Y Sensitized Cs2PtSnCl6 Perovskites for Enhanced Photocatalytic Hydrogen Evolution

Vacancy-ordered Cs₂SnX₆ perovskites, with low-toxicity and high stability, have emerged as promising photocatalysts for hydrogen evolution reaction (HER). However, most Cs₂SnX₆ and derivatives have low catalytic activity mainly due to their insufficient light utilization efficiency. Herein, a simple in situ method is introduced to sensitize Cs₂PtSnCl₆ with Eosin Y (EY), forming EY-Cs₂PtSnCl₆ for HER in aqueous solution. Various characterizations indicate that the EY is immobilized onto the Cs₂PtSnCl₆ during the synthesis process. The EY-Cs₂PtSnCl₆ displayed extended light absorption range and efficient charge transfer from EY to Cs₂PtSnCl₆. The resulting EY-Cs₂PtSnCl₆ material exhibits high HER rate of 17.6 mmol g⁻¹ h⁻¹, ≈1760 folds than that of the pristine Cs₂PtSnCl₆. This work demonstrates an effective method to construct dye-sensitized perovskites and highlights the importance of interaction between dye and perovskite. It provides useful guidance for the design of new perovskite-based photocatalysts and it will advance the development of perovskites for solar energy conversion into renewable fuels.