Enhanced Charge Carrier Lifetime of TiS3 Photoanode by Introduction of S22− Vacancies for Efficient Photoelectrochemical Hydrogen Evolution

Abstract Recent advances in layered TiS 3 has shown appealing potential for photoelectrochemical hydrogen evolution due to its excellent optical and electronic properties. Here, an excellent photoanode, composed of TiS 3 nanoribbon arrays with moderate S 2 2− vacancies, is proposed to achieve efficient photoelectrochemical hydrogen evolution. These unique S 2 2− vacancies are introduced in the TiS 3 photoanode by a simple vacuum re‐annealing method, which is inspired by crystal structure analyses of TiS 3 and TiS 2 . The existing S 2 2− vacancies are revealed to significantly promote the electron conductivity, charge separation, and transport of the photoanode simultaneously. The resulting TiS 3− x photoanode with ≈22% S 2 2− vacancies exhibits a twofold increase in the electron diffusion length for efficient electron collection and a remarkably high photocurrent density of 15.35 mA cm −2 at 1.4 V versus reversible hydrogen electrode.