Preparation and Photocatalytic Activities of TiO2-Based Composite Catalysts

Abstract

While modern industry has contributed to the prosperity of an increasingly urbanized society, it has also led to serious pollution problems, with discharged wastewater and exhaust gases causing significant environmental harm. Titanium dioxide (TiO2), which is an excellent photocatalyst, has received extensive attention because it is inexpensive and able to photocatalytically degrade pollutants in an environmentally friendly manner. TiO2 has many advantages, including high chemical stability, low toxicity, low operating costs, and environmental friendliness. TiO2 is an N-order semiconductor material with a bandgap of 3.2 eV. Only when the wavelength of ultraviolet light is less than or equal to 387.5 nm can the valence band electrons obtain the energy of the photons and pass through the conduction band and form photoelectrons, while the valence band, correspondingly, forms photogenerated holes, and light in other areas will not be generated. The most common methods used to improve the photocatalytic efficiency of TiO2 involve increasing its photoresponse range and reducing photogenerated-carrier coupling. The morphology, size, and structure of a heterojunction can be altered through element doping, leading to improved photocatalytic efficiency. Mainstream methods for preparing TiO2 are reviewed in this paper, with several excellent preparation schemes for improving the photocatalytic efficiency of TiO2 introduced. TiO2 is mainly prepared using sol-gel, solvothermal, hydrothermal, anodic oxidation, microwave-assisted, CVD and PVD methods, and TiO2 nanoparticles with excellent photocatalytic properties can also be prepared. Ti-containing materials are widely used to purify harmful gases, as well as contaminants from building materials, coatings, and daily necessities. Therefore, the preparation and applications of titanium materials have become globally popular research topics.

Composites of Montmorillonite and Titania Nanoparticles Prepared by Inverse Microemulsion Method: Physico-Chemical Characterization

“…It should be recalled that the interest in the development of titania-based nanocomposites is not limited to photocatalysis and catalysis but also stems from their wide application in photovoltaics, hydrogen storage, sensors, biomedicine, and electronics [ 1 , 8 , 9 , 10 , 11 , 12 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. The synthetic procedure described in this work is aimed specifically at the formation of titanium-clay hybrid systems but can be readily adapted to the deposition of TiO 2 nanoparticles in a variety of matrices or can be used to prepare finely dispersed clay nanoparticles for potential use in other clay-based composites such as, e.g., clay-reinforced polymers.…”

A review of research trends on the usage of photocatalysis for wastewater treatment: bibliometric analysis

“…The first known photocatalysts were wide bandgap semiconductors (Bitaraf and Amoozadeh 2021 ). Despite their popularity and effectiveness, they have significant drawbacks of absorption only at UV region, hence limiting their photocatalytic activity (Yang et al 2022 ). Besides, it is already known that solar energy comprises only 3–5% UV, whereas 43% of solar energy comprises visible light, therefore a significant amount of solar radiation is lost (Yang et al 2022 ).…”

Unraveling the origin of the high photocatalytic properties of earth-abundant TiO2/FeS2 heterojunctions: insights from first-principles density functional theory

“…Among them, TiO 2 has attracted the most attention as an active photocatalyst for several environmental and energy applications owing to its abundance, low cost, chemical stability, non-toxicity, and resistance toward photocorrosion. 15,16 However, the restricted light absorption ability (3-5% of the entire sunlight spectrum) owing to the wide band gap (3.2-3.35 eV) and the fast recombination of photogenerated electron-hole pairs remain as two major factors that limit the practical applications of TiO 2 . 17 To overcome these limitations and promote efficient separation of photogenerated charge carries, various strategies including doping, 18 metal loading, 19 surface modification, 20 and introducing heterojunctions 21 have been adopted.…”