Sonochemical reassembling of Acacia nilotica bark extract mediated Mg doped WO3@g-C3N4 ternary nanocomposite: A robust nanophotocatalyst

Abstract

One of the most significant environmental issues of the modern era is malachite green dye wastewater due to its high toxicity, susceptibility for mutagenicity, and carcinogenicity. In order to tackle this problem, we prepared Z-scheme type Mg-doped WO3 supported onto g-C3N4 ternary photocatalyst by sonochemical intercalating Mg into WO3@g-C3N4 binary composite in the Acacia nilotica bark extract medium. X-ray diffraction, SEM, EDS, HR-TEM, photoluminescence, and BET surface area analysis were used to explore the structural, morphological and surface characteristics. The findings indicated that the formation of highly crystalline with aggregated lump-based flakiness and various nano-sized crystals in stacked layers with smooth assemblies were taken place. The photoluminescence spectra illustrated that the annihilation of the plasmonic excitons was sufficiently suppressed in ternary composite. Under solar light irradiation, the designed Mg doped WO3@g-C3N4 ternary nanocomposite shown better photocatalytic activity for Malachite green (MG) degradation than undoped g-C3N4 and WO3@g-C3N4 binary composite. It was also investigated how physical parameters like pH, and catalyst dose affected the photo-degradation of MG as well as examined the recyclability up to 4 cycles. The radical scavenging studies suggested that the primary species responsible for the breakdown of MG by the Mg doped WO3@g-C3N4 ternary nanophotocatalyst materials is the •O2– radicals. Photodegradation of MG followed pseudo-first order kinetics with highest rate constant 0.090 min−1 using ternary composite. The superior visible radiation absorption, enhanced surface area, improved separation efficacy of excited e--h+ couples, and the photo-generated electron movement from g-C3N4 to WO3 bands via Mg can all be contributed to the ternary WO3@g-C3N4 nanocomposite’s excellent photocatalytic performance as well as recyclability.