Facile fabrication of mesoporous BiOCl/(BiO)2CO3/Bi2O3 ternary flower-like heterostructured microspheres with high visible-light-driven photoactivity

A novel anion exchange method followed by a simple solid-state reaction process has been developed for the controllable synthesis of mesoporous BiOCl/(BiO)(2)CO3/Bi2O3 ternary flower-like heterostructured microspheres (HMSs) using uniform BiOCl microspheres as templates. Firstly, the transformation of BiOCl microspheres into BiOCl/(BiO)(2)CO3 binary HMSs was achieved through a facile in situ anion exchange reaction in the presence of Na2CO3 aqueous solution at 80 degrees C for 8 h. Secondly, the mesoporous BiOCl/(BiO)(2)CO3/Bi2O3 ternary HMSs were obtained by thermal decomposition of the BiOCl/(BiO)(2)CO3 composites at 400 degrees C for 4 h in air. Importantly, the Bi2O3 and (BiO)(2)CO3 content in the ternary system can be conveniently tuned by varying the Na2CO3 concentration in the anion exchange reaction process. Benefiting from unique structural features, the as-obtained mesoporous BiOCl/(BiO)(2)CO3/Bi2O3 ternary flower-like HMSs exhibit remarkably enhanced photocatalytic activity for the degradation of organic pollutants under visible-light irradiation compared with BiOCl/(BiO)(2)CO3 and Bi2O3/(BiO)(2)CO3 binary composites and the mechanical mixture of BiOCl, Bi2O3, and (BiO)(2)CO3 (BBB-mixture), and the total organic carbon (TOC) removal rate could reach 67% after irradiation for 60 min. Furthermore, a test for radical scavengers indicated that photogenerated holes (h(+)) and superoxide anion radicals (O-2(center dot-)) were the main reactive species in the BiOCl/(BiO)(2)CO3/Bi2O3 ternary composites.