Synthesis, characterization, and photocatalytic activity of silver and zinc co-doped TiO₂ nanoparticle for photodegradation of methyl orange dye in aqueous solution

Abstract

In this study, TiO2 nanocrystals, 1 mol% Ag-doped TiO2, and 1 mol% Ag and 0.6 mol% Zn co-doped TiO2 powders were synthesized by the sol–gel route. Their photocatalytic activities on methyl orange dye under visible irradiation were investigated. The powders were characterized by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), Brunauer–Emmett–Teller (BET), and Fourier transform infrared spectroscopy (FTIR). The XRD results revealed the presence of a rutile phase with an average crystallite size of 9 and 11 nm. The UV–vis spectra showed a red-shift towards a longer wavelength with the corresponding decrease in band gap from 2.9 to 2.5 eV. The BET surface areas of the nanoparticles ranged from 4.7 to 11.8 m2 g−1 with an average pore size between 18.9 and 56.6 nm. The Ag-doped TiO2 has the largest surface area of 11.8 m2 g−1, whereas the Ag–Zn co-doped TiO2 was found to have the highest pore size and volume. The absorption bands at 750–500 cm−1 were attributed to the –O–Ti–O– bond in the TiO2 lattice. The photocatalytic efficiency was highest at an optimum pH of 4.1 for Ag–Zn co-doped TiO2. The results confirmed that Ag-doped and Ag–Zn co-doped TiO2 were more effective than pure TiO2. The kinetic data were fitted into a pseudo first-order equation using a Langmuir–Hinshelwood kinetic model.

Impact of Titanium Dioxide (TiO2) Modification on Its Application to Pollution Treatment—A Review

“…Co-doped nanoparticles exhibit higher visible light absorption than single doped TiO 2 due to a synergistic effect between the two dopants, which can efficiently increase the photocatalytic performance [150]. Co-doping can be divided into different metal elements co-doping [151][152][153], metal elements and non-metal elements doping [154][155][156] and different non-metal elements doping [157][158][159]. As shown in Table 2, many researchers have used co-doping method to modify TiO 2 and tested the photocatalytic performance of the materials.…”

LaFeO₃ Modified RuO₂ for Enhancing Electrochemical Performances

“…No diffraction peaks of perovskite-type oxide LaFeO3 is found from the XRD spectra due to the low doping level. The crystallite sizes of the samples are calculated by Scherrer Equation[10] according to the peaks of (110) plane, and the corresponding size of the RuO2 and RuO2-LaFeO3 samples are 35.1 nm and 33.0 nm, respectively, indicating that LaFeO3 nanoparticles doping can lead to crystallite size decrease.EDS of the RuO2 and the RuO2-LaFeO3 samples was carried out to analyze the composition. The ratio of O, Ru, La and Fe in the RuO2-LaFeO3 sample is 68.4:30.6:0.5:0.6.…”