Zr-Doped β-In2S3 Ultrathin Nanoflakes as Photoanodes: Enhanced Visible-Light-Driven Photoelectrochemical Water Splitting

Photoelectrochemical (PEC) water splitting via semiconductor is a promising approach to the scalable generation of renewable H2 fuels. Several characteristics are crucial for efficient water splitting in PEC cell systems, including low onset potential for the photoanode, high photocurrent, and long-term stability. In this study, we investigated metal ion doping application to prepare 2, 5, and 8 mol % Zr-doped β-In2S3 two-dimensional nanoflakes; we then used the material to create improved photoelectrodes for PEC water splitting. That Zr4+ doping in the crystal lattice of β-In2S3 led to red-shift absorption of the 40 nm wavelength, which benefits visible-light utilization. Three nanoflake samples were tested for use as PEC water splitting electrodes and compared to pure β-In2S3 nanoflakes. We found that the photocurrent density of 2 mol % Zr-doped β-In2S3 nanoflakes was nearly 10 times higher than that of pure β-In2S3 nanoflakes at 1.2 V versus a reversible hydrogen electrode (RHE). In addition, the anodic photocurrent onset had a 0.15 V negative shift compared to pure β-In2S3 nanoflakes. The strategy we propose here can likely be used to develop other n-type semiconducting photoanodes for use in low-cost, solar-fuel-generation devices.