Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment

Z. P. Tshabalala, D. E. Motaung, G. H. Mhlongo, O. M. Ntwaeaborwa

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)

Abstract

TiO2 nanoparticles were synthesized via a simple hydrothermal method in a sodium hydroxide (NaOH) aqueous solution and washed with distilled water and different concentrations of hydrochloric acid which acted as the morphological/crystallographic controlling agent. Microscopy analysis showed that the size of the TiO2 nanoparticles could be easily tailored and tuned by varying the HCl concentration. The phase transformation from a mixture of anatase and rutile phases to pure anatase phase was observed at higher HCl concentration. The particle sizes were reduced while the Brunauer-Emmett-Teller surface area increased when increasing the HCl concentration, thus resulting in higher sensing response and selectivity to NO2 at room temperature. The X-ray photoelectron spectroscopy, photoluminescence and electron paramagnetic resonance studies also revealed that the 1.0 M sample contain high relative concentration of oxygen vacancy and Ti4+ and Ti3+ interstitial defect states which played a vital role modulating the sensing properties.

Original languageEnglish
Pages (from-to)841-856
Number of pages16
JournalSensors and Actuators B: Chemical
Volume224
DOIs
Publication statusPublished - 1 Mar 2016
Externally publishedYes

Keywords

  • Gas sensing
  • HCl
  • Morphology
  • NO
  • TiO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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