AMORPHOUS SILICA-SUPPORTED ZrO2-WO3 MESOPOROUS NANOCOMPOSITE FROM AGRO-INDUSTRIAL WASTE (COCONUT COIR): SUSTAINABLE HETEROGENEOUS CATALYST FOR 4H-CHROMENE SYNTHESIS

This study presents a green and cost-effective preparation of amorphous silica-supported ZrO2-WO3 mesoporous nanocomposite from agro-industrial waste, specifically coconut coir. Amorphous silica (AS) was obtained through a sustainable extraction process from coconut coir, and the amorphous silica-supported-ZrO2-WO3 (ASS-ZWOM) nanocomposite was prepared using the wet impregnation technique. The structural features and compositional details of the prepared ASS-ZWOM nanocomposite were evaluated using several advanced analytical techniques. FT-IR analysis confirmed the Si-O-Si vibrations, and the composite exhibited additional Zr-O and W-O bands, indicating the successful metal oxide incorporation. FE-SEM images revealed that the nanocomposites are below 100 nm. Energy-dispersive X-ray spectroscopy was used for element composition, and Raman spectroscopy for studying molecular vibrations. BET measurement demonstrated mesoporosity with a surface area of 2.68 m2/g and a pore diameter of 2.36 nm. This study highlights the potential of agro-industrial waste-derived materials for producing high-performance catalysts, demonstrating a sustainable catalytic route for synthesizing 4H-chromene.