Green photocatalysis focuses on developing processes to address various environmental challenges, such as the treatment of contaminated water and air, the generation of renewable energy, biomass management, carbon monoxide oxidation, and organic synthesis. TiO2 has a wide array of applications in green photocatalysis, including (i) photocatalytic remediation and (ii) the development of alternative, sustainable energy sources. A significant challenge in modern green photocatalysis is the reduction of the band gap energy (Eg), which is essential for determining the suitability of materials for photocatalytic activity. Decreasing Eg enables TiO2 to effectively harness visible light rather than being limited to ultraviolet light. This study investigates the structural changes and subsequent reduction in Eg resulting from two types of TiO2 modification: (i) ionising irradiation and (ii) the incorporation of carbon nanotubes. The structural changes were studied by X-ray powder diffraction and Raman spectroscopy, while Eg of the samples was assessed through UV-Vis spectroscopy.
ThangaduraiPBeuraRKumarJS. Nanomaterials with different morphologies for photocatalysis. In: NaushadMRajendranSLichtfouseE (eds) Green photocatalysts. Switzerland: Springer Nature, 2000, pp.47–87.
2.
PeirisSde SilvaHBRanasingheKN, et al.Recent development and future prospects of TiO2 photocatalysis. J Chin Chem Soc2021; 68: 739–769.
3.
MeinholdG. Rutile and its applications in earth sciences. Earth Sci Rev2010; 102: 1–28.
4.
PerksCMuddG. Titanium, zirconium resources and production: a state of the art literature review. Ore Geol Rev2019; 107: 629–646.
5.
TahirMBSohaibMSagirM, et al.Role of nanotechnology in photocatalysis. Encycl Smart Mater2022; 2: 578–589.
6.
FujishimaAHondaK. Electrochemical photolysis of water at a semiconductor electrode. Nature1972; 238: 37–38.
7.
LuttrellTHalpegamageSTaoJ, et al.Why is anatase a better photocatalyst than rutile? Model studies on epitaxial TiO2 films. Sci Rep2014; 4: 4043.
8.
ZaleskaA. Doped-TiO2: a review. Recent Pat Eng2008; 2: 157–164.
9.
KanounMBAhmedFAwadaC, et al.Band gap engineering of Au doping and Au–N codoping into anatase TiO2 for enhancing the visible light photocatalytic performance. Int J Hydrogen Energy2024; 51: 907–913.
10.
ToyodaMYanoTTrybaB, et al.Preparation of carbon-coated Magneli phases TinO2n–1 and their photocatalytic activity under visible light. Appl Catal B2008; 88: 160–164.
11.
AnHParkSYKimH, et al.Advanced nanoporous TiO2 photocatalysts by hydrogen plasma for efficient solar-light photocatalytic application. Sci Rep2016; 6: 29683.
12.
PriyankaKPJosephSSunnyAT, et al.Effect of high energy electron beam irradiation on the optical properties of nanocrystalline TiO2. Nanosystems: Phys Chem Math2013; 4: 218–224.
DiabKRDoheimMMMahmoudSA, et al.Gamma-Irradiation improves the photocatalytic activity of Fe/TiO2 for photocatalytic degradation of 2-chlorophenol. Chem Mater Res2017; 9: 49–60.
15.
WangWDSerpPKalckP, et al.Visible light photodegradation of phenol on MWNT-TiO2 composite catalysts prepared by a modified sol–gel method. J Mol Catal A: Chem2005; 235: 194–199.
16.
PaunovićPGrozdanovAMakreskiP, et al.Structural changes of TiO2 as a result of CNTs incorporation. Mater Sci & Eng2022; 6: 31–39.
17.
LattheSSAnSJinS, et al.High energy electron beam irradiated TiO2 photoanodes for improved water splitting. J Mater Chem A2013; 1: 13567–13575.
18.
WronskiPSurmackiJAbramczykH, et al.Surface, optical and photocatalytic properties of silica-supported TiO2 treated with electron beam. Radiat Phys Chem2015; 109: 40–47.
19.
SurahSSVishwakarmaMKumarR, et al.Tuning the electronic band alignment properties of TiO2 nanotubes by boron doping. Results Phys2019; 12: 1725–1731.
20.
DongZLiWWangH, et al.Carbon nanotubes in perovskite-based optoelectronic devices. Matter2022; 5: 448–481.
21.
ShabanMAshrafAMAbukhadraMR. Tio2 nanoribbons/carbon nanotubes composite with enhanced photocatalytic activity; fabrication, characterization, and application. Sci Rep2017; 8: 781.
22.
PaunovićPGrozdanovAMakreskiP, et al.Application of ionizing irradiation for structure modification of nanomaterials. In: PetkovPAchourMEPopovC (eds) Nanoscience and nanotechnology in security and protection against CBRN threats. Dordrecht, The Netherlands: Springer Nature B.V., 2020, pp.23–43.
ChoiHCJungYMKimSB. Size effects in the Raman spectra of TiO2 nanoparticles. Vib Spectrosc2005; 37: 33–38.
25.
ParkerJCSiegelRW. Raman Microprobe study of nanophase TiO2 and oxidation-induced spectral changes. J Mater Res1990; 5: 1246–1252.
26.
KhanMMAnsariSAPradhanD, et al.Band gap engineered TiO2 nanoparticles for visible light induced photoelectrochemical and photocatalytic studies. J Mater Chem A2014; 2: 637–644.
27.
XuCYZhangPXYanL. Blue shift of Raman peak from coated TiO2 nanoparticles. J Raman Spectrosc2001; 32: 862–865.
28.
GuiMMChaiS-PXuB-Q, et al.Visible-light-driven MWCNT@TiO2 core–shell nanocomposites and the roles of MWCNTs on the surface chemistry, optical properties and reactivity in CO2 photoreduction. RSC Adv2014; 4: 24007–24013.
29.
SahaAMoyaAKahntA. Interfacial charge transfer in functionalized multi-walled carbon nanotube@TiO2 nanofibres. Nanoscale2017; 9: 7911–7921.
