Exploring structural and optical properties of iodine-doped TiO2 nanoparticles in Rhodamine-B dye degradation: Experimental and theoretical investigation

• Published in: Chemosphere (Oxford) Vol. 364; p. 143183
• Main Authors: Raguram, T., Rajni, K.S., Kanchana, D., José, Solar-Encinas, Granados-Tavera, Kevin, Cárdenas-Jirón, Gloria, Shobana, M., Meher, S.R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2024
• Subjects: DFT studies; Dye-degradation; I-doped TiO2; Nanoparticles; UV-DRS; XRD; Nanoparticles; I-doped TiO2; XRD; UV-DRS; DFT studies; Dye-degradation
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2024.143183

Energy conversion and pollutant degradation are critical for advancing sustainable technologies, yet they often encounter challenges related to charge recombination and efficiency limitations. This study explores iodine-doped TiO2 nanoparticles as a potential solution for enhancing both energy conversion and pollutant degradation. The nanoparticles were synthesized via the sol-gel method with varying iodine precursor concentrations (0.025–0.1 M) and were characterized for their structural, compositional, and optical properties, particularly in relation to their photocatalytic performance in Rhodamine-B dye degradation. X-ray diffraction confirmed a tetragonal anatase crystal structure, with the average crystallite size decreasing from 10.06 nm to 8.82 nm with increase in iodine concentration. Selected area electron diffraction patterns verified the polycrystalline nature of the nanoparticles. Dynamic light scattering analysis showed hydrodynamic radii ranging from 95 to 125 nm. Fourier-transform infrared spectroscopy identified metal-oxygen vibrations at 441 cm⁻1, and electron microscopy confirmed the spherical morphology of the nanoparticles. Elemental analysis detected the presence of Ti, O, and I in the samples. Diffuse reflectance spectroscopy indicated the optical absorption edges for the doped samples in the visible region from which the corresponding band gap values were deduced. Photoluminescence spectroscopy revealed that the sample with 0.1 M iodine exhibit the lowest emission intensity, suggesting reduced charge recombination. Notably, 0.1 M iodine doped TiO2 samples demonstrated the highest photocatalytic efficiency, achieving 82.36% degradation of Rhodamine-B dye within 140 min under visible light. Additionally, ab-initio density functional theory calculations were performed to investigate the structural, optical, and adsorption properties of TiO2, iodine-doped TiO2, Rhodamine-B, and their composites, providing further insight into the enhanced photocatalytic activity observed in the experiments. [Display omitted] •I-doping on TiO2 by sol-gel technique and analyzing the structural and optical properties compared with theoretical results.•Avg. crystallite sizes are less than 10 nm and spherical shaped nanoparticles.•Optical absorption edge is shifted from UV to visible region upon I-doping.•Optimum iodine dopant concentration for higher Rhodamine-B dye degaradation efficiencies with support of theoretical results.