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

Abstract

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 (S_BET) 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 ˙O²⁻ 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.