Mechanistic Understanding in Manipulating Energetics of TiO₂ for Photocatalysis

Abstract

Titanium dioxide (TiO2) is a wide bandgap semiconductor that has a wide range of applications including wastewater treatment, photocatalysis, solar cells, and sensors owing to its excellent electronic and optical properties. However, the wide bandgap of TiO2 (∼3.2 eV) along with the recombination processes of the photoexcited charge carriers reduce its interfacial charge transport properties and respective activities. Energetics, optical response, and corresponding photophysics of excited charge carriers can be altered through doping and codoping of TiO2 and composite formulation. Therefore, it is very crucial to understand the structure–property and property-application relationships of doped, co-doped, and composite TiO2 to maximize the efficiency and extend the fundamental understanding for their applications in different fields. In this Perspective, we summarize the ongoing research on the advancement of undoped, doped, co-doped, and composite TiO2 including their structure and morphology, energetics, and corresponding photophysics relative to their applications in photocatalysis, wastewater treatment, and water-splitting reactions. We then propose our perspectives on the future potential of energetic manipulation of photocatalytic TiO2 to develop advanced and highly efficacious catalytic materials.

Nanohybrid Composites Based on TiO2 and Single-Walled Carbon Nanohorns as Promising Catalysts for Photodegradation of Amoxicillin

“…A 12.3% decrease in the efficiency of AMOX photodegradation occurs when the TiO 2 /SWCNH composite, with an SWCNH concentration equal to 10%, is used as catalyst, which highlights the good stability of this catalyst and its ability to be reused in the photodegradation processes of waters polluted with such pharmaceutical compounds. An explanation for this behavior must take into consideration that the TiO 2 /SWCNH composite can absorb the full spectrum of incident light, like TiO 2 [33], thereby generating heat at the interface of the TiO 2 /SWCNH composite because the SWCNH powder is black. One consequence of this heat generation is that it will increase the migration of the electronhole pair into the mass of the TiO 2 /SWCNH composite, thus inducing an increase in charge separation that leads to a greater photocatalytic effect than that of TiO 2 [34].…”

Surface Defect Engineered Nano‐Cu/TiO2 Photocatalysts for Hydrogen Production

“…[ 3,8 ] Furthermore, large specific surface area, high crystallinity and anatase phase are known to increase photocatalytic activity. Intense investigations are still ongoing on different aspects of photocatalytic activity of TiO 2 , which can be exploited to improve its performances, including doping and co‐doping, [ 9 ] nanostructuring, [ 10 ] defect engineering, [ 11,12 ] reactor configuration, [ 13 ] heterostructuring, [ 14 ] among the others.…”

Perspective, Review, and Featured Articles of 2023

“…TiO 2 is widely used as a photocatalyst despite the fact that its large band gap requires absorption of ultraviolet light. While doping can address some of the issues of catalysis on TiO 2 surfaces, the effects of modifying other parameters such as crystal form and shape/size of nanoparticles are summarized in Hossain et al…”