Facile fabrication of BiOCl/RGO/protonated g-C3N4 ternary nanocomposite as Z-scheme photocatalyst for tetracycline degradation and benzyl alcohol oxidation

A novel ternary BiOCl/RGO/PCN nanocomposite was successfully fabricated through coupling-protonated g-C3N4 (PCN) sheets with GO by electrostatic attraction, followed by in situ synthesis of BiOCl layers on the surface on PCN/GO via hydrothermal reaction and simultaneously achieving the reduction in GO. The as-prepared BiOCl/RGO/PCN composite exhibited significantly enhanced photoactivities toward the degradation of representative antibiotic tetracycline and selective aerobic oxidation of benzyl alcohol compared to pristine g-C3N4, protonated g-C3N4, pure BiOCl and binary BiOCl/PCN composite under simulated solar light irradiation. The structure-property relationship was explored by several effective characterization techniques. The results show that RGO coordinated well with two semiconductors of BiOCl and PCN, and BiOCl/RGO/PCN composite with closely contacted interface exhibited broad optical adsorption range and effective photogenerated charge carrier separation efficiency, which are attributed to the improved photocatalytic performance. The results also demonstrate that a Z-scheme charge process was formed between BiOCl and PCN with RGO serving as electron transfer medium to promote the fast transporting of photoinduced electrons. Therefore, more photoinduced electrons and holes could retain in the CB of PCN and in the VB of BiOCl with strong redox ability, respectively, which is beneficial to the further effective generation of active radicals participating in photocatalytic reaction. This work provides a promising Z-scheme ternary photocatalyst with facile synthetic method and potential application in environmental pollution elimination and green oxidative organic transformation.