Atomic-Scale Insights into the Activation of Near-Infrared- Responsive Photoactivity in BiOCl Grain Boundaries

Two-dimensional bismuth oxychloride (BiOCl) is a promising semiconductor material in energy production and environmental remediation because of its high surface areas and exposed uncoordinated atoms. However, its development is hindered by the large band gap (∼3.40 eV). In this work, using density functional theory, we have demonstrated that ∑5 (120) and ∑5 (310) grain boundaries (GBs) barely change the electronic structure of pristine BiOCl, while ∑13 (320) GB significantly reduces the transition energy barrier of electron and broadens the optical absorption range to near-infrared (NIR). More importantly, the employed structures are stable and their electronic structures can be well maintained at room temperature, according to the molecular dynamic (MD) simulations. Our results suggest that tuning the types of GBs can significantly improve the ability of optical absorption of the BiOCl photocatalyst and provide an alternative way for designing excellent semiconductor photocatalysts.