Gallium- and iodine-co-doped titanium dioxide for photocatalytic degradation of 2-chlorophenol in aqueous solution: Role of gallium

Photocatalytic Degradation of Organic Dye by Sol‐Gel‐Derived Gallium‐Doped Anatase Titanium Oxide Nanoparticles for Environmental Remediation

“…As far as the difference between our work against the previously reported sol-gel-derived Ga-doped (or Ga/I codoped) TiO 2 nanomaterials is concerned [37,38], both of these reports indicated the formation of phase impure TiO 2 nanopowders with a mixture of anatase and rutile (as well as a small fraction of brookite) phases under Ga (or Ga/I) (co-)doping, whereas we have been able to obtain phase pure anatase TiO 2 nanoparticles (as shown later) via our solgel route. It has been reported previously that phase pure anatase TiO 2 (along with commercially available Degussa P-25) has the highest hydroxyl radical ( • OH) formation rate under photoirradiation, which is considered to be the main species responsible for the photooxidation of organic compounds [10].…”

“…Apparently, sol-gel deposition process is preferred (at least in the research scale) over vacuumbased as well as hydrothermal syntheses, mainly because of its simplicity and cost-effectiveness in terms of materials, design, process, and implementation. As far as the reason behind the adoption of Ga as the doping material is concerned, previously few authors reported the improved photocatalytic activities of TiO 2 : Ga (and TiO 2 : Ga/I codoped) nanomaterials in terms of solar hydrogen production and photodecomposition of various organic compounds used in disinfectants and pesticides [36][37][38][39][40][41]. The comparable ionic radii of Ta +4 (68 pm) and Ga +3 (62 pm) appears to be favorable for the substitutional doping of Ga atoms into the Ti matrix to improve the optical, electronic, and photocatalytic properties.…”

“…Therefore, it is desirable to synthesize phase-pure anatase TiO 2 for efficient photodegradation of organic molecules, and, in that respect, our process to synthesize phase-pure Ga-doped anatase TiO 2 nanoparticles may become very important for efficient photocatalytic organic waste management. Also, for the application of waste water treatment via TiO 2 : Ga-based photocatalytic degradation of organic molecules, photocatalytic oxidation of water soluble organic dyes (like Rhodamine B, as in our case) should be preferred as the testing agent against sparingly soluble organic substances (like 2-chlorophenol, 1,4-dichlorobenzene, and so forth, as used in [37,38]), because the water soluble toxic dyes released from textile industries in the surface water as waste products pose considerable threats to the environment and, hence, warrants proper attention. 2.2.…”

Improvement of Orange II Photobleaching by Moderate Ga3+ Doping of Titania and Detrimental Effect of Structural Disorder on Ga Overloading

“…Iodinedoped titania photocatalysts were improved by doping with gallium and the resulting physicochemical properties and photocatalytic activity were investigated. Gallium ions played a decisive role in retarding the anatase-rutile phase transformation, extending the absorption spectrum and creating oxygen vacancies for photoelectron trapping to prevent the e − − h + recombination process [12]. Copper-and galliumdoped titania photocatalysts prepared by means of sol-gel technique and analysed by XRD were found to contain specific crystalline phases of anatase, -Ga 2 O 3, and Cu 2 O, which allowed inferring on the doping phenomena of both transition and posttransition metals [13].…”

Synthesis, morpho-structural characterization and environmental application of titania photocatalysts obtained by rapid crystallization

“…Song et al [33] no/ 400 °C no/air no/ 2h not specified Song et al [108] no/ 400, 500 °C not specified no/ 2h not specified Song et al [110] yes/ 400, 500, 600 °C not specified no/ 2h no/ 5 °C/min Szatmáry et al [28] yes/ 400, 500, 600, 700 °C not specified no/ 3h no/ 5 °C/min…”