Z-scheme heterojunction ZnSnO3/rGO/MoS2 nanocomposite for excellent photocatalytic activity towards mixed dye degradation

Abstract

In this work, a novel (ZnSnO3/rGO/MoS2) nanocomposite was prepared and its photocatalytic performances were investigated. The synthesised ZnSnO3 spheres were well dispersed over the surface of rGO sheet and MoS2 layers (ZSGM). The structural, morphological and elemental properties of the composites were examined by XRD, SEM, HRTEM and EDS. The surface chemical composition and functional groups of the elements interlinked in the composites were identified from XPS and FTIR analysis. BET and Raman analysis indicate the effective formation between MoS2/rGO/ZnSnO3 ternary heterostructure nanocomposite. The suppressed photogenic charge carrier's recombination rate was investigated by PL analysis. From UV analysis, the bandgap of ZSGM nanocomposite was successfully tuned from 3.13 eV to 2.70 eV, leading to high photocatalytic performance by mixed dye pollutant under UV-visible light illumination. The ZSGM photocatalyst achieved highest removal rate of 0.0131 min−1 for Rh B degradation, and 0.0153 min−1 for MB dye degradation and efficiency was 78% (Rh B) and 86% (MB), respectively in 100 min, which shows dramatically enhanced activity than other samples. In the presence of rGO/MoS2 in ZS, ZSGM photocatalysts exhibit higher catalytic activity due to a lower bandgap, more absorption in the visible region, and suppressed recombination rate of photogenerated e−/h+ pairs.