Using Er/Cd-Codoped Bi₄O₅Br₂ Microspheres to Enhance Antibiotic Degradation under Visible Illumination: A Combined...

High levels of antibiotic accumulation and the difficulty of degradation can have serious consequences for the environment and, therefore, require urgent attention. To solve this problem, a synergistic Er and Cd ion-codoped Bi₄O₅Br₂ photocatalyst was proposed. The degradation rate of sulfamethoxazole (SMX) by Er/Cd-Bi₄O₅Br₂ was eight times higher than that of pure Bi₄O₅Br₂, exceeding that of single Er-doped or Cd-doped Bi₄O₅Br₂, which was attributed to the ability of Er/Cd-Bi₄O₅Br₂ to generate a variety of free radicals. Experimental results and theoretical calculations suggested a possible mechanism for the improved photocatalytic degradation rate. The reduction of the band gap can facilitate the production of electron-hole pairs, which play a significant role in the production of reactive radicals. Furthermore, an optimal stabilized structure of the ErCd-Bi₄O₅Br₂ dopant system was identified based on the formation energy formulas of different ligand configurations. These findings offer promising potential for the degradation of broad-spectrum antibiotics and provide valuable insights for the design and modification of photocatalytic materials.