Narrowing the Band Gap of BiOCl for the Hydroxyl Radical Generation of Photocatalysis under Visible Light

It remains an exciting challenge to achieve a direct production of large quantities of ^{" ¢}OH, generated from photogenerated h⁺ using visible-light-driven photocatalysts fabricated by a one-step method. In this work, a series of hierarchical interconnected BiOCl materials with a tunable absorption range for visible light have been successfully prepared through a one-pot molecular self-assembly technology at room temperature. Depending on the modification of polar organic molecules [i.e., thiourea (TU)], the nonpolar layered semiconductor (BiOCl) turned into an efficient visible-light photocatalyst because it possesses a narrower band gap by surface modification introducing oxygen defects. Meanwhile, the tunable three-dimensional hierarchical architecture of BiOCl was fabricated via the self-assembly of two-dimensional nanosheets with the aid of TU, leading to an enhanced specific surface area along with efficient electron-hole pair separation. Moreover, the obtained BiOCl-10 showed a more positive valence band with an optimized hierarchical porous structure, which produced a sufficient amount of ^{" ¢}OH directly from the reaction between photogenerated h⁺ and water molecules under visible light. Thereby, the BiOCl-10 materials exhibit high photocatalytic activities for almost completely degrading tetracycline and rhodamine B in 20 min, about 20 times better than that of pure BiOCl. Our work provided an innovation strategy that may deliver a promising way to fabricate BiOCl materials with highly efficient visible photocatalytic activity by direct production of large quantities ^{" ¢}OH through its photogenerated h⁺.