S-rGO modified sulphur doped carbon nitride with mixed-dimensional hierarchical nanostructures of silver vanadate for the enhanced photocatalytic degradation of pollutants in divergent fields

Abstract A sheet on sheet (2D/2D) structure of highly conductive S-rGO on S-gC3N4 promote effective transfer of electrons for Cr(VI) reduction and subsequent degradation of organic pollutants. The photocatalytic activity of the 2D/2D hybrid material is significantly increased by the decoration of α-Ag3VO4 hollow nanoflowers through ultrasonic assisted Kirkendall effect. The inter-particle electronic coupling in hollow nanoflower leads to self-narrowing of the band gap. The in-situ fabrication of β-AgVO3 nanowires to form a quaternary catalyst enhanced the photocatalytic activity and corrosion inhibition by supporting a combined conventional and Z-scheme mechanism. This enhanced photocatalytic activity is due to the synergistic effects of heterostructured semiconductor photocatalysis, increased surface area, improved utilization of solar light due to hollow structure, decreased photocorrosion and the surface plasmon resonance(SPR) of Ag0. The photocatalytic activities of S-gC3N4/S-rGO/Ag3VO4/AgVO3(SGO-SGA-x) composite photocatalysts were measured by the degradation of methylene blue(MB), methyl Orange(MO), 2,4-dichlorophenoxy acetic acid(2,4-D) and Cr(VI) reduction under visible-NIR irradiation. Electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectral analysis indicated that the in-situ formation of β-AgVO3 from Ag3VO4 could efficiently promote the separation efficiency of photogenerated charge carriers. Our present work indicated that the photocatalytic activity can be significantly enhanced by judiciously designing the semiconductor nanomaterials.