Semiconductor Nanocomposites for Visible Light Photocatalysis of Water Pollutants

Abstract

Semiconductor photocatalysis gained reputation in the early 1970s when Fujishima and Honda revealed the potential of TiO 2 to split water in to hydrogen and oxygen in a photoelectrochemical cell. Their work provided the base for the development of semiconductor photocatalysis for the environmental remediation and energy applications. Photoactivity of some semiconductors was found to be low due to larger band gap energy and higher electron-hole pair recombination rate. To avoid these problems, the development of visible light responsive photocatalytic materials by different approaches, such as metal and/or non-metal doping, codoping, coupling of semiconductors, composites and heterojunctions materials synthesis has been widely investigated and explored in systematic manner. This chapter emphasizes on the different type of tailored photocatalyst materials having the enhanced visible light absorption properties, lower band gap energy and recombination rate of electron-hole pairs and production of reactive radical species. Visible light active semiconductors for the environmental remediation purposes, particularly for water treatment and disinfection are also discussed in detail. Studies on the photocatalytic degradation of emerging organic compounds like cyanotoxins, VOCs, phenols, pharmaceuticals, etc., by employing variety of modified semiconductors, are summarized, and a mechanistic aspects of the photocatalysis has been discussed.

Stimulated generation of photobiogas by morphologically tuned nanostructured ZnO and ZnO/TiO2

“…Peaks between 2830 and 3000 cm –1 are due to the C–H stretching vibration of alkane groups, which may be attributed to the residues of the capping agents after washing [ 38 , 42 – 44 ]. The absorption peaks in the 400–700 cm −1 could be attributed to the ZnO stretching modes [ 43 – 45 ].…”

Photocatalytic activity of CuO nanoparticles for organic and inorganic pollutants removal in wastewater remediation

“…Volume 300, August 2022, 134623. PREPRINT (submitted version) https://www.sciencedirect.com/science/article/pii/S004565352201116X?via%3Dihub https://doi.org/10.1016/j.chemosphere.2022.134623 reactions [44]. Pure CuO has a bulk bandgap of 1.2 eV and this value could reach up to 3.57 eV in the nanoscale size regime by adjusting synthesis methods [45].…”

The practicality and prospects for disinfection control by photocatalysis during and post-pandemic: A critical review

“…On the contrary, the visible- and/or NIR-light active photocatalytic materials show profound penetration ability leading to effective oxidation destruction of the viral cell ( Parra-Ortiz and Malmsten, 2021 ). Of note, vast modification strategies such as metal/non-metal doping, co-doping, heterostructure formation, defect engineering have been systematically explored to overcome the hurdle associated with less energy utilization and conversion ( Imtiaz et al, 2019 ). However, the research on modified nanomaterials for antiviral activity still needs further exploration.…”