Photocatalytic Degradation of Crystal Violet Dye under Visible Light by Fe-Doped TiO2 Prepared by Reverse-Micelle Sol–Gel Method

Abstract

A reverse-micelle sol–gel method was chosen for the preparation of Fe-doped TiO2 samples that were employed in the photodegradation of the crystal violet dye under visible light irradiation in a batch reactor. The dopant amount was varied to assess the optimal photocatalyst composition towards the target dye degradation. The photocatalysts were characterized through a multi-technique approach, envisaging XRPD and QPA as obtained by Rietveld refinement, FE-SEM analysis, DR UV−vis spectroscopy, N2 adsorption/desorption isotherms measurement at −196 °C, ζ-potential measurement, and XPS analysis. The physical-chemical characterization showed that the adopted synthesis method allows obtaining NPs with uniform shape and size and promotes the introduction of Fe into the titania matrix, finally affecting the relative amounts of the three occurring polymorphs of TiO2 (anatase, rutile and brookite). By increasing the Fe content, the band gap energy decreases from 3.13 eV (with undoped TiO2) to 2.65 eV (with both 2.5 and 3.5 wt.% nominal Fe contents). At higher Fe content, surface Fe oxo-hydroxide species occur, as shown by DR UV-vis and XP spectroscopies. All the Fe-doped TiO2 photocatalysts were active in the degradation and mineralization of the target dye, showing a TOC removal higher than the undoped sample. The photoactivity under visible light was ascribed both to the band-gap reduction (as confirmed by phenol photodegradation) and to dye sensitization of the photocatalyst surface (as confirmed by photocatalytic tests carried out using different visible-emission spectra LEDs). The main reactive species involved in the dye degradation were determined to be positive holes.

Ultraviolet-Induced Gas Sensing Performance of Ag/WO3/rGO Nanocomposites for H2S Gas Sensors

“…Under the influence of UV light, the valence band electrons migrate in the conduction band, increasing the number of electron and hole residences in the nanocomposite (as shown in process (i) in Figure 10b). 47,48 The adsorbed oxygen and gas ions can gain energy from UV photons and be excited, leading to an increase in the electron concentration on the sensor (as shown in process (ii) in Figure 10b). 49,50 The increase in electron concentration promotes the adsorption of H 2 S and the formation of oxygen ions in the reaction with the free electrons trapped in the conduction band, as shown in Figure 10d.…”

Synthesis rifaximin with copper (Rif-Cu) and copper oxide (Rif-CuO) nanoparticles Considerable dye decolorization: An application of aerobic oxidation of eco-friendly sustainable approach

“…Industrial expansion and environmental pollution have negative effects on human health, with water contamination being a serious problem, particularly in wastewater from the food, beverage, leather, cosmetic, dyeing, textile, and printing industries. Traditional wastewater treatment methods are generally insufficient for dealing with synthetic dyes, which may persist in the environment for extended periods and harm ecosystems [ 32 ]. Coomassie Brilliant Blue G250 and Rhodamine B are examples of dyes with various chemical structures.…”

A Photocatalysis of CV Dye Under UV Light Degradation using Laboratory Prepared In(OH)3 And In2O3 By Hydrothermal Method: Nano-Matrrials For Dye Sensitive Solar Cell

“…Non-biodegradable pollutants in air and water are eliminated by using some semiconductors [1][2][3][4][5][6][7]. Usually, oxide semiconductors have higher band gap (5.5 eV).…”

“…It is for this reason, Indium oxide and hydroxide are studied exhaustibly for their physico-chemical properties as well as for their potential applications in various electronic fields [1,9]. In(OH)3 is observed to be an useful photocatalyst used for the removal of benzenes as compared to other materials such as P2O5, TiO2 [2][3][4][5][6][7]10]. It has now been accepted that In2O3 would be a suitable semiconductor for application in gas sensor, transparent conductors, solar cells and solid-state application devices [11].…”