Integrated Heterostructure of PDA/Bi‐AgIn₅S₈/TiO₂ for Photoelectrochemical Hydrogen Production: Understanding the Synergistic Effect of Multilayer Structure

Abstract

Abstract Overcoming one of most challenging limitations of bare TiO 2 with large bandgap can be achieved by rational design and fabrication of heterostructures. Multicomponent sulfides with a nature of tunable band structure can be a good alternative to decorating TiO 2 , but there remains a major trade‐off between the high efficiency and the long‐term durability, so the stability issue must be addressed upon the use of sulfides. Here, an effective strategy is demonstrated with Bi‐doped AgIn 5 S 8 (Bi‐AgIn 5 S 8 ) decorated TiO 2 photoanode, where twofold enhancement of the photocurrent is achieved. More importantly, it is the first time to integrate polydopamine passivation layer and AgIn 5 S 8 for simultaneously enhancing the solar conversion efficiency and stability. The incident photon‐to‐current conversion efficiency value is tuned up to 45% (0.4 V vs Ag/AgCl), and the photocurrent density can keep for 90.8% after 5 h. Corresponding hydrogen evolution rate has increased to 8.6 µmol h −1 , which is three times higher than that of bare TiO 2 .