Two dimensional S-scheme BiWO-TiO-TiC nanocomposites for efficient degradation of organic pollutants under natural sunlight.

Two-dimensional (2D) materials have fascinated the researchers to exploit their properties including large surface area, ability to act as a support and to form face-to-face interfacial contact with other 2D materials for fabricating efficient photocatalytic materials. In this work, BiWO, TiO and TiC nanosheets have been used synthesizing different series of binary BiWO-TiO and ternary BiWO-TiO-TiC 2D nanocomposites by an electrostatic self-assembly synthesis route. The as-prepared pristine materials and binary and ternary nanocomposites were characterized by different structural, morphological and compositional characterization techniques to confirm their successful synthesis and 2D morphology. It was found that the optimized BiWO-TiO (20 wt%) and BiWO-TiO (20 wt%)-TiC (5 wt%) nanocomposites showed 97.0% and 98.5% degradation of methyl green in 80 min and 40 min, respectively, which was higher than their pristine counterparts. The enhanced activity was credited to the large surface area offered by 2D nanocomposites, pollutant adsorption and enhanced photogenerated charge separation and transfer facilitated by S-scheme mechanism and face-to-face interfacial contact of different components of these nanocomposites. This work delivers an example of highly efficient 2D nanocomposites and discusses the role of TiC as an electron acceptor in S-scheme photocatalytic system.