Exploring the thickness dependent photocatalytic oxygen evolution performance for Bi4TaO8Cl two-dimensional semiconductor

The utilization of solar energy for water splitting has great potential to alleviate the worsening environmental issues. Two-dimensional (2D) materials, possessing tunable band gap, large surface area with more active sites, and short photogenerated carriers migrating distance, have attracted massive research interests as promising photocatalysts. In the water splitting reaction, compared with the hydrogen evolution reaction, the four elementary steps of oxygen evolution reaction (OER) is a complex and difficult reaction. Among 2D materials, Bi4TaO8Cl exhibits great potential for the OER. It is worth noting that the thicknesses of 2D materials is a significant factor for modifying physicochemical properties. However, the thickness dependence of OER performance remains unclear in Bi4TaO8Cl. Here, we systematically studied the effects of thicknesses on photocatalytic performance. Interestingly, we found that the few-layer Bi4TaO8Cl possesses more remarkable photocatalytic properties than monolayer Bi4TaO8Cl deriving from interlayer coupling effect. Compared with monolayer Bi4TaO8Cl, the few-layer exhibits broader range of light absorption accompanied with larger transition dipole moment, stronger reduction potential to drive the OER, and lower recombination probability of photogenerated electron and hole. The interlayer coupling interaction improves the photocatalytic properties, which promotes the progress of 2D material at photocatalytic water splitting reaction.