Visible light-driven removal of Rhodamine B using indium-doped zinc oxide prepared by sol–gel method

Abstract

Industrial dye contamination in wastewater poses significant environmental challenges, necessitating the development of efficient photocatalysts for degradation. In this work, we investigate the In doping effect in the photocatalytic activity of zinc oxide (ZnO) nanoparticles for effective RhB degradation. Indium-doped ZnO nanoparticles were synthesized via sol–gel method and x-ray diffraction (XRD) analysis revealed a wurtzite hexagonal structure, with the crystallite size being varying from 65 nm to 53 nm with the introduction of In content. XPS measurements on the 3% In-doped ZnO sample revealed distinct core level spectra for In 3d, Zn 2p, and O 1s regions, confirming the presence of indium, zinc, and oxygen. Brunauer–Emmett–Teller (BET) analysis revealed increased surface area and pore size, with specific surface areas escalating from 0.9 m²/g for pure ZnO to 10.1 m²/g for 3% indium-doped ZnO. Photocatalytic experiments exhibited significant RhB degradation, with degradation efficiencies reaching 93% for 3% indium-doped ZnO under visible light irradiation due to the effect of the presence of In, which causing light absorption enhancement, narrow the band gap and improve charge carrier separation. These findings underscore the potential of indium-doped ZnO nanoparticles as efficient and sustainable photocatalysts for wastewater treatment, offering a promising avenue to address environmental challenges associated with industrial dye-contaminated effluents.

Graphical Abstract