Controlled Synthesis of Hollow PbS‐TiO 2 Hybrid Structures through an Ion Adsorption–Heating Process and their Photocatalytic Activity

Hollow hybrid nanostructures have received significant attention because of their unique structural features. This study reports a facile ion adsorption–heating method to fabricate hollow PbS‐TiO 2 hybrid particles. In this method, the TiO 2 spheres used as a substrate material to grow PbS are aggregates of many small amorphous TiO 2 particles, and each small particle is covered with thioglycolic acid ligands through Ti 4+ –carboxyl coordination. When Pb 2+ ions are added to a colloidal solution of these TiO 2 spheres, these ions are adsorbed by sulfhydryl (‐SH) groups to form metal thiolates, and the C−S bond is dissociated by heating to release S 2− . The S 2− ions react with Pb 2+ ions to form PbS without additive sulfur sources. Additionally, the amorphous TiO 2 spheres are transformed into the anatase phase during the heating process. As a result, the crystallization of TiO 2 spheres along with the formation of PbS is simultaneously carried out by heating. During the heating process, owing to the Kirkendall effect of S 2− diffusion and the Ostwald ripening effect of the crystallization of amorphous TiO 2 spheres, PbS‐TiO 2 hollow hybrid structures can be obtained. The XRD and XPS characterizations proved the formation of anatase TiO 2 and PbS. The TEM characterization confirmed the formation of hollow structures in the PbS‐TiO 2 hybrid sample. The photocatalytic activity of the hollow PbS‐TiO 2 hybrid spheres have been investigated for the degradation of Cr 6+ under visible light. The results show that hollow PbS‐TiO 2 hybrid spheres exhibited the highest photocatalytic activity, in which almost all the Cr 6+ was degraded after 140 min.