Tunable photocatalytic selectivity of TiO2/SiO2 nanocomposites : Effect of silica and isolation approach

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

22 Scopus Citations
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Author(s)

  • Esfandiar Pakdel
  • Shayan Seyedin
  • Jinfeng Wang
  • Joselito M. Razal
  • Lu Sun
  • Xungai Wang

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)130-141
Journal / PublicationColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume552
Online published16 May 2018
Publication statusPublished - 5 Sep 2018

Abstract

TiO2 nanoparticles have widely been used as a photocatalyst to eliminate organic contaminants from wastewater. However, the lack of selectivity is considered as one of the main drawbacks of TiO2 nanoparticles in wastewater treatment applications. To overcome this problem, this study aims at developing highly adsorbent photocatalysts with tunable selective photocatalytic activity. To this end, the selective photocatalysts of anatase TiO2 nanoparticles and TiO2/SiO2 nanocomposites with different surface charges were synthesized through a sol-gel method. TiO2/SiO2 nanocomposites were prepared based on three molar ratios of Ti:Si, which were 1:0.43, 1:1, and 1:2.33. Two isolation procedures of base-precipitation (BP method) and solvent-evaporation (SE method) were adopted to extract the nanoparticles from the colloids and clarify their impact on selective performance of the photocatalysts. The sequential decolorization processes of aqueous dye solutions consisting of methylene blue (MB) and methyl orange (MO) in the presence of photocatalysts were monitored under UV illumination and used as probes to compare the selective behaviors of TiO2 and TiO2/SiO2 powders. The results revealed that while commercial TiO2 (Degussa P-25) decomposed both dyes non-selectively, the synthesized photocatalysts induced a selective and sequential decomposition of dyes. The samples prepared through the BP and SE methods showed selective adsorption and photocatalytic activity in favor of cationic MB and anionic MO dye molecules, respectively. The presence of silica significantly increased the MB dye adsorption on photocatalysts prepared through BP method compared with pure TiO2. The isolation method of nanoparticles had a direct impact on surface charge and selective performance of photocatalysts.

Research Area(s)

  • Adsorption, Nanocomposite, Selective photocatalysis, Sol-gel method, TiO2

Citation Format(s)

Tunable photocatalytic selectivity of TiO2/SiO2 nanocomposites : Effect of silica and isolation approach. / Pakdel, Esfandiar; Daoud, Walid A.; Seyedin, Shayan; Wang, Jinfeng; Razal, Joselito M.; Sun, Lu; Wang, Xungai.

In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 552, 05.09.2018, p. 130-141.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review