An Unprecedented Strategy to Fabricate Inside/Surface Homojunction in Bismuth Oxychloride for Efficient Photocatalysis

Abstract

The design of an efficient homojunction in bismuth oxychloride via simple means is still challenging. Herein, an inside/surface homojunction of bismuth oxychloride via fabricating surface-layer oxygen vacancies from a sulfur dopant and surface-layer hydroxyl from an alkali modification (BOCSO) in a one-pot hydrothermal process is successfully prepared. BOCSO exhibits enlarged specific surface area, improved adsorption of substrate, and enhanced photogenerated charge separation and transfer efficiencies. Extensive characterizations and density functional theory (DFT) calculations demonstrate BOCSO can form a defect level via surface oxygen vacancies and S doping to narrow the energy gap and capture the photogenerated electrons and holes. Meanwhile, both oxygen vacancies and hydroxyls on the BOCSO surface can also form an inside/surface homojunction containing an interfacial electric field (IEF) to induce a direct Z-scheme charge transfer mechanism. Taking advantage of the above, the photocatalytic degradation activity is remarkably elevated compared to that of pristine BiOCl (BOC). This work provides a new strategy for the fabrication of an inside/surface homojunction in bismuth oxychloride via novel surface modification engineering.