Rational sonochemical engineering of Ag₂CrO₄/g-C₃N₄ heterojunction for eradicating RhB dye under full broad spectrum

In this novel research, S-scheme Ag₂CrO₄/g-C₃N₄ heterojunctions were generated by sonochemical hybridization of different compositions of Ag₂CrO₄ nanoparticles [E_VB = +2.21 eV] and g-C₃N₄ sheets [E_CB = -1.3 eV] for destructing RhB dye under artificial solar radiation. The as-synthesized nanocomposites were subjected to X-ray diffraction [XRD], diffuse reflectance spectrum [DRS], X-ray photoelectron spectroscopy [XPS], N₂-adsorption-desorption isotherm, photoluminescence [PL] and high resolution transmission electron microscope [HRTEM] analysis to explore the interfacial interactions between g-C₃N₄ sheets and Ag₂CrO₄ nanoparticles. Spherical Ag₂CrO₄ nanoparticles deposited homogeneously on the wrinkles points of g-C₃N₄ sheets at nearly equidistant from each other facilitating the uniform absorption of solar radiations. The absorbability of solar radiations was enhanced by introducing 20 wt % Ag₂CrO₄ on g-C₃N₄ sheets. The surface area of g-C₃N₄ sheets was reduced from 37.5 to 16.4 m²/g and PL signal intensity diminished by 80 % implying the successful interfacial interaction between Ag₂CrO₄ nanoparticles and g-C₃N₄ sheets. The photocatalytic performance of heterojunctions containing 20 % Ag₂CrO₄ and 80 % g-C₃N₄ destructed 96 % of RhB dye compared with 60 and 33 % removal on the surface of pristine g-C₃N₄ sheets and Ag₂CrO₄, respectively. Benzoquinone and ammonium oxalate are strongly scavenged the dye decomposition revealing the strong influence of valence band holes of Ag₂CrO₄ and superoxide radicals in destructing RhB dye under solar radiations. S-scheme charge transportation mechanism was suggested rather than type II heterojunction on the light of scavenger trapping experiments results and PL spectrum of terephthalic acid. Overall, this research work illustrated the manipulation of novel S-scheme heterojunction with efficient redox power for destructing various organic pollutants persisted in water resources.