Hydrothermal synthesis of porous CdS/Bi2S3/BiOIO3 nanocomposites for solar-driven photocatalytic degradation of rhodamine B

Abstract

A heterojunction structure incorporating three photocatalysts, corresponding to a ternary composite CdS/Bi2S3/BiOIO3, was proposed to address the issues of poor stability, low efficiency in utilizing visible light, and poor performance in degrading refractory organic pollutants for conventional photocatalysts. Therefore, the interconnected CdS/Bi2S3/BiOIO3 structure facilitated the transfer of electrons from Bi2S3 to BiOIO3 by reducing the band gap, as well as the transfer of h+ from BiOIO3 to Bi2S3. As a result, slow carrier recombination and a decreasing band gap were found, resulting in the good performance of RhB degradation. As a medium, CdS could improve the e- and h+ transmission efficiency between Bi2S3 and BiOIO3. According to performance measurements, after excluding the influence of adsorption, the photocatalytic activity of CdS/Bi2S3/BiOIO3 reached 94.22 % after 30 min and remained stable after five cycles. A quenching experiment illustrating the importance of superoxide and hydroxyl radicals in RhB degradation, which might be applied to other refractory organic contaminants. DRS studies demonstrated that the composite combines the benefits of CdS and Bi2S3, with better light absorption across a broader wavelength range. According to the photocatalytic mechanism, the formation of a compact, three-component heterostructure at the interface increases light absorption while decreasing electron-hole recombination. The results of corresponding novels may yield valuable insights for the development of an effective approach in the design of a high-performance photocatalysis system for the degradation of pollutants.