Semiconductor Photocatalysis for Water Purification

Semiconductor Electrode Materials Applied in Photoelectrocatalytic Wastewater Treatment—an Overview

“…A combination of two or more semiconductors with appropriately selected band gaps and the energy of CB and VB is a method of improvement of photocatalyst activity [174]. Such combined semiconductors are applied as photoelectrode materials in wastewater treatment.…”

Highly Porous and Ultra-Lightweight Aero-Ga2O3: Enhancement of Photocatalytic Activity by Noble Metals

“…On the other hand, the excited electrons in the conduction band are able to produce superoxide anion radicals (O 2 •− ) upon reacting with O 2 . Both (•OH) and (O 2 •− ) are free radicals and being strong oxidants are able to mineralize organic and inorganic carbon compounds producing carbon dioxide, water, and other smaller organic molecules [ 8 , 10 , 27 , 28 , 51 , 52 , 53 ].…”

“…Different approaches have been proposed for enhancing the photocatalytic performance of catalysts, such as making use of co-catalysts, the development of semiconductor-based hybrid photocatalysts, crystal phase engineering, and the rational design of phase junctions [ 24 ], e.g., via implementing heterojunctions [ 25 , 26 , 27 , 28 ]. Furthermore, coupling photocatalysts with conductive materials and utilizing the surface plasmon resonance (SPR) to produce plasmonic photocatalysis [ 26 , 27 , 28 , 29 , 30 ] show promising outcomes.…”

“…Different approaches have been proposed for enhancing the photocatalytic performance of catalysts, such as making use of co-catalysts, the development of semiconductor-based hybrid photocatalysts, crystal phase engineering, and the rational design of phase junctions [ 24 ], e.g., via implementing heterojunctions [ 25 , 26 , 27 , 28 ]. Furthermore, coupling photocatalysts with conductive materials and utilizing the surface plasmon resonance (SPR) to produce plasmonic photocatalysis [ 26 , 27 , 28 , 29 , 30 ] show promising outcomes. By implementing these approaches, the following issues were addressed: (i) the light absorption region was extended by combining various photosensitizers with semiconductors, particularly by deposition of nanoparticles (NPs) of noble metals such as gold (Au), silver (Ag), and platinum (Pt) to enhance visible light absorption due to SPR; (ii) suppression of electron–hole recombination through efficient charge separation and confinement of the photogenerated electrons and holes in different components of semiconductor-based heterostructures or by using conductive materials, particularly noble metal NPs or carbon materials as electron acceptors and traps to enhance the carrier separation in photocatalysts and to avoid the recombination of charges; (iii) surface reactions were enhanced by integrating co-catalysts with semiconductors.…”

Comparison of Photocatalytic Efficiency of TiO2 and In2S3 Thin Films under UV and Visible Light Irradiance

“…The dye molecules too get excited under the irradiation which results in movement of electrons to the CB of the catalyst [38]. In general, the excited electrons have strong reduction capacity while holes possess strong oxidation capacity and therefore, they would act as reductant and oxidant respectively [39]. The excited electron in the conduction band reacts with air to generate super oxide radical anions (O 2 − ).…”