Cl-doped Bi2S3 homojunction nanorods with rich-defects for collaboratively boosting photocatalytic reduction performance

Due to the slow charge separation and low efficiency of surface reactive site, developing efficient catalysts to achieve the conversion of toxic Cr (VI) to non-toxic Cr (III) faces huge challenges. Herein, a synthesis route by involving homojunction and surface defects is employed to design defect-rich Cl-doped Bi2S3 homojunction nanorods, which considerably boosted the aqueous Cr (VI) photoreduction activity without co-catalyst, extra photosensitizer or sacrificial agent. Cl-doped Bi2S3 nanorods with surface sulfur defect are grown via the sulfuration of BiOCl and the doping of Cl. The homojunction originates from oriented attachment of the nanoparticles by controlling the synthesis conditions and the introduction of Cl-. Analysis of the defects and homojunctions disclosed that the sulfur defects are mainly concentrated on the exposed {1-12} facet of the homojunction rather than the exposed {010} facet. The engineered sulfur defects are able to tune the electronic structure of Cl-doped Bi2S3 and serve as the surface active site to activate adsorbed pollutant species. Meanwhile, the homojunction structure with different exposed facets can enhance the electron-hole separation. Thanks to homojunction and surface defects, the defect-rich Cl-doped Bi2S3 homojunction nanorods display 19 and 45 times improved Cr (VI) photoreduction rate than the Bi2S3 and BiOCl.