Modulation of Photoactive Nanocomposite Cu Doped SnO2 Anchored on G-C3N4 Polymeric Sheets by Green Synthesis and Degradation of Dye Malachite Green

Abstract

Wastewater containing harmful dyes such as Malachite green poses a significant environmental challenge because of its high levels of carcinogenicity, mutagenicity, and toxicity. To address this issue, we developed a photocatalyst consisting of Cu doped SnO₂ nanocomposite supported onto g-C₃N₄ using green synthesis method with the assistance of Murraya paniculata leaves extract. To know about the structural, morphological chemical composition of the synthesized heterojunction several techniques of characterization techniques were employed such as XPS, XRD, BET, HRTEM, FESEM, EDAX and UV-Vis spectra. XRD results shows the spherical shape of the particles with the mean grain size of 2.18 and 2.14 nm for Cu doped SnO₂ and Cu doped SnO₂/g-C₃N₄ respectively. HRTEM results reveal that the fabricated Cu doped SnO₂ shows formation of very small size spherical nanoparticles. The heterojunction Cu doped SnO₂/g-C₃N₄ showed 2-D sheeted structure of g-C₃N₄ which acts as a translucent layer that captured sphere shaped Cu doped SnO₂ NPs. The XPS analysis verifies the existence of Sn, Cu, O, C and N in the synthesized heterojunction. The UV-Visible spectra helped to demonstrate the effective inhibition of plasmonic exciton annihilation within the heterojunction nanocomposite. When exposed to solar light, the designed nanocomposite heterojunction exhibited superior photocatalytic activity in the degradation of MG compared to undoped g-C₃N₄ and Cu doped SnO₂ binary nanocomposite. Radical scavenging studies indicated that •O2– radicals were the principle species accountable for the degradation of MG by the nanocomposite heterojunction. The dye MG photodegraded with pseudo-first order kinetics. The excellent photocatalytic performance and recyclability of nanocomposite can be attributed to its greater surface area, improved separation efficiency of excited e--h+ pairs and superior absorption of visible light.