Tailoring S-scheme-based carbon nanotubes (CNTs) mediated Ag-CuBi2O4/Bi2S3 nanomaterials for photocatalytic dyes degradation in the aqueous system

In this study, S-scheme-based hydrothermal synthesis of Ag-CuBi2O4/CNTs/Bi2S3 layered composites has been successfully reported. The photo-degradation of toxic dyes, viz. methyl orange (MO), and methylene blue (MB), has been used to examine nanocomposites with varying weight percent of Bi2S3 for photocatalytic activity in the visible range. Among candidates, Ag-CuBi2O4/CNTs/Bi2S3 with a 10% loading of Bi2S3 outperformed both pure and hybrid composites in photocatalytic activity. For MO degradation, the hybrid composite with 10% Bi2S3 loading degrades 7.04 times higher than pristine CuBi2O4 and Bi2S3 samples, and for MB degradation, it degrades 4.96 times higher than pristine samples. High surface area, less recombination rate of photogenerated charge carriers, photogenerated carriers faster separation, and high redox ability of Ag-CuBi2O4/CNTs/Bi2S3 (10%) are all attributed to the improving photocatalytic performance. Even after ten cycles, the hybrid composite is chemically stable and reusable. Carbon nanotubes (CNTs) are a transfer bridge in layered structure for electrons because of their coordinated Fermi level between Ag-CuBi2O4 and Bi2S3. In addition, the scavenger and electron spin resonance (ESR) experiments verified that ∙O2−, ∙OH, and h+ were the important reactive species that successfully facilitated the photocatalytic degradation process to degrade dyes. This study presents a straightforward and economical approach for obtaining a stable semiconductor-based photocatalytic system and a potential technique for future applications.