TiO2-Based Heterostructure Containing g-C3N4 for an Effective Photocatalytic Treatment of a Textile Dye

Abstract

Water pollution has become a serious environmental issue. The textile industries using textile dyes are considered to be one of the most polluting of all industrial sectors. The application of solar-light semiconductor catalysts in wastewater treatment, among which TiO2 can be considered a prospective candidate, is limited by rapid recombination of photogenerated charge carriers. To address these limitations, TiO2 was tailored with graphitic carbon nitride (g-C3N4) to develop a heterostructure of g-C3N4@TiO2. Herein, a simple hydrothermal synthesis of TiO2@g-C3N4 is presented, using titanium isopropoxide (TTIP) and urea as precursors. The morphological and optical properties and the structure of g-C3N4, TiO2, and the prepared heterostructure TiO2@g-C3N4 (with different wt.% up to 32%), were analyzed by various laboratory methods. The photocatalytic activity was studied through the degradation of methylene blue (MB) aqueous solution under UV-A and simulated solar irradiation. The results showed that the amount of g-C3N4 and the irradiation source are the most important influences on the efficiency of MB removal by g-C3N4@TiO2. Photocatalytic degradation of MB was also examined in realistic conditions, such as natural sunlight and different aqueous environments. The synthesized g-C3N4@TiO2 nanocomposite showed superior photocatalytic properties in comparison with pure TiO2 and g-C3N4, and is thus a promising new photocatalyst for real-life implementation. The degradation mechanism was investigated using scavengers for electrons, photogenerated holes, and hydroxyl radicals to find the responsible species for MB degradation.

Obtaining TiO₂ Nanostructures by Electrospinning and Analysis of Absorbance in the UVA Spectrum for Photocatalytic Application

“…The W 6+ sites capture the electrons that are promoted to the conduction band, causing the reduction of the ions. The holes, can dissociate H 2 O molecules or organic molecules that donate protons, which are adsorbed on the surface of the particles [8]. The reflection/absorption of light modifies the color of the material, generating positively charged O 2 gaps that capture the photoexcited electrons [11].…”

Microwave Synthesis of (g‐C3N4)−BiVO4: Selective Adsorption and Photocatalytic Activity Towards Dye Degradation

“…The most common routes to the synthesis of graphitic carbon nitride involve thermal methods through pyrolysis of urea [8], melamine [9], and dicyandiamide [19] . Typically, the procedures require calcination temperature varying from 500–550 °C [19–20] in one or two steps, [20a,e] from 2 to 4 hours [19,20b–d,f–h] . Hydrothermal methodologies have been little investigated and are restricted to using melamine as a precursor [21] .…”

“…Hydrothermal methodologies have been little investigated and are restricted to using melamine as a precursor [21] . The resultant particles exhibit irregular shapes, [19b,20a,b,22] nanosheets, [20c,e,g,21] layered wrinkled structures of g‐C 3 N 4 , [20d] fractal layered structures, [20f] and tubular [20h] …”