Synergistic Experimental-Theoretical DFT Study on the Photocatalytic Properties of Fibrous Silica-Titania and MoS₂ Nanostructures

Abstract

Photocatalytic degradation presents a sustainable and effective approach for addressing environmental pollution and wastewater treatment issues. This study investigates the synthesis of MoS2 and Fibrous Silica Titania (FST) photocatalysts using eco-friendly hydrothermal methods to enhance the degradation of the industrial dye Methylene Blue (MB). Density Functional Theory (DFT) calculations were performed to investigate the electronic structure and optical properties of FST and MoS2 nanomaterials. The computed band structure and density of states reveal enhanced visible-light absorption and effective charge carrier separation, and reduced electron–hole recombination.The structural characteristics of these materials cockscomb-like nanospheres for FST and a layered structure for MoS2 were analysed using X-ray diffraction (XRD), which confirmed their high crystallinity and purity. Morphological analysis through Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) revealed distinct spherical and dendritic Fiber morphologies for FST and a layered configuration for MoS2. Optical properties, assessed by UV-vis spectroscopy, indicated bandgaps of 1.75 eV for FST and 1.90 eV for MoS2, which contribute to their enhanced photocatalytic activity under visible light. FST exhibited exceptional degradation performance, achieving 99.34% MB degradation, due to its high surface area, efficient charge carrier separation, and reduced electron-hole recombination rate, as confirmed by photoluminescence (PL) measurements. Fourier Transform Infrared Spectroscopy (FTIR) identified key functional groups that provide insights into the photocatalytic mechanisms. Additionally, surface area and pore size analyses using BET confirmed the suitability of these photocatalysts for environmental applications. Our results highlight FST and MoS2 as promising, cost-effective, and high-performance materials for the photocatalytic treatment of organic pollutants.