High-Performance alpha-Bi2O3/CdS Heterojunction Photocatalyst: Innovative Design, Electrochemical Performance and DFT Calculation

Heterojunction semiconductor photocatalysis is an auspicious technique for clear up organic pollutants from water, and have been of valuable strategy in the area of photocatalysis. Herein, electrophoretic deposition procedure was used to prepare alpha-Bi2O3/CdS type-II heterojunction photocatalysts. The results of photoluminescence (PL), Raman, and electrochemical impedance spectroscopy (EIS) show that there is a heterojunction effect in alpha-Bi2O3/CdS, which is propitious to improve the separation efficiency of photogenerated electron-hole pairs. The density functional theory (DFT) calculation reveals that the work function of CdS (CS1, 4.57 eV) is higher than that of alpha-Bi2O3 (alpha-BO, 3.37 eV), which facilitates the migrating of e- from the conduction band (CB) of alpha BO to the CB of CS1, and the migrating of h(+) from the valence band (VB) of CS1 to the VB of alpha BO, thus the electron-hole (e(-)-h(+)) pairs with high redox ability are retained. The performances were assessed by degrading methyl orange (MO), acid magenta under simulated visible light irradiation. Under simulated visible light irradiation, BC45 composite exhibited the highest degradation efficiency of 87% (MO) and 81% (acid fuchsin) for 4 h, which was about 2 times higher than that of CS1 (MO) and (acid fuchsin). It is believed that the dual characteristics of H2O wettability and dye adsorption performance in alpha-Bi2O3/CdS composites promote photocatalytic process compared with single alpha-BO and CS1. The study could provide new insights to develop efficiently capable photocatalysts of the alpha-Bi2O3/CdS composites.