Preparation of CdS nanoparticle loaded flower-like Bi₂O₂CO₃ heterojunction photocatalysts with enhanced visible light photocatalytic activity.

In this work, a series of novel flower-like Bi2O2CO3/CdS heterojunctions were prepared by a simple and feasible two-step process. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD). Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to confirm the flower-like heterostructures of the Bi2O2CO3/CdS composites. The Brunauer-Emmett-Teller (BET) specific surface area (SBET) of samples were analyzed by N2 adsorption-desorption isotherms. UV-vis diffuse reflectance spectrometry (DRS) revealed that Bi2O2CO3/CdS heterojunctions exhibited better light absorptive properties than pure Bi2O2CO3. The photocatalytic activity was investigated by the degradation of MB under visible light irradiation. The results showed that the as-prepared Bi2O2CO3/CdS heterojunctions exhibited much higher activity than pure Bi2O2CO3. The photoluminescence (PL) spectra and photocurrent studies indicated that the recombination of photogenerated electron-hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and CdS nanoparticles. Trapping experiments indicated that ˙O(2-) radicals were the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Bi2O2CO3-CdS composites.