Preparation of a ternary g-C3N4-CdS/Bi4O5I2 composite photocatalysts with two charge transfer pathways for efficient degradation of acetaminophen under visible light irradiation

It is a challenge to explore highly efficient photocatalysts for the degradation of pharmaceutical contaminant under visible light. In this work, a series of g-C3N4-CdS/Bi(4)O(5)I(2 )composites were prepared by a simple self-assembly and calcination method. The photocatalysts showed good photocatalytic activity and stability for acetaminophen degradation. The enhanced activity and stability can be ascribed to the reason that the formed ternary heterojunctions provided multi-channel for the transfer of photogenerated charges. Meanwhile, the visible light absorption capacity was improved effectively because of the addition of Bi4O5I2. Furthermore, the transfer of holes from CdS to g-C3N4 prohibited the photocorrosion of CdS, thus improving the stability of the composites. The apparent rate constant of the optimal sample (g-C3N4-CdS/Bi4O5O2) for acetaminophen degradation was 5 and 2.5 times as that of g-C3N4-CdS and pure Bi4O5I2. The degradation pathway of acetaminophen was proposed based on the detected intermediates. This work provided an idea to design multi-heterojunction photocatalysts with high performance for the degradation of drug pollutants.

Automated summary

A series of g-C3N4-CdS/Bi(4)O(5)I(2) composites with good photocatalytic activity and stability for acetaminophen degradation were prepared in this study. The enhanced performance is attributed to the formation of ternary heterojunctions providing multiple channels for photogenerated charge transfer and the improved visible light absorption capacity with the addition of Bi4O5I2. Additionally, the transfer of holes from CdS to g-C3N4 helped prevent photocorrosion of CdS, enhancing the stability of the composites.