Microenvironment Regulation of the electronic structure of bismuth oxychloride via rare-earth element Samarium doping for remarkable Visible-Light-Responsive oxygen evolution

Abstract

Bismuth-based oxyhalides have attracted considerable research interest for visible-light-responsive oxygen evolution reaction, however, their ineffective light absorption and charge separation efficiencies remain a challenge. Herein, a novel visible-light-responsive 2D Bi₂SmO₄Cl nanosheet photocatalyst was designed by introducing rare-earth element Sm into BiOCl and thus its electronic structure microenvironment is commendably tailored to promote the light absorption and charge separation. Moreover, iodine doping and IrO₂ cocatalyst are employed to give rise to IrO₂-Bi₂SmO₄Cl_1-xI_x with a remarkable O₂-evolving rate of 151.2 μmol·h⁻¹ under visible light irradiation, which is more than 500-fold of pristine BiOCl. Both the Sm introduction and I doping significantly shorten the band gap and increase the charge separation efficiency. The density functional theory (DFT) calculation demonstrated that Sm can give electrons to other atoms, benefits the charge separation process and decreases the work function of oxygen evolution reaction. This work can offer new insights into the design and structure modulation of bismuth-based oxyhalides.