Composites of carboxylate-capped TiO2 nanoparticles and carbon black as chemiresistive vapor sensors

Edgardo García-Berríos, Ting Gao, Don Walker, Bruce S. Brunschwig, Nathan S. Lewis

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Titanium (IV) dioxide (TiO2) nanoparticles (NPs) with a 1-5 nm diameter were synthesized by a sol-gel method, functionalized with carboxylate ligands, and combined with carbon black (CB) to produce chemiresistive chemical vapor sensor films. The TiO2 acted as an inorganic support phase for the swellable, organic capping groups of the NPs, and the CB imparted electrical conductivity to the film. Such sensor composite films exhibited a reproducible, reversible change in relative differential resistance upon exposure to a series of organic test vapors. The response of such chemiresistive composites was comparable to, but generally somewhat smaller than, that of thiol-capped Au NPs. For a given analyte, the resistance response and signal-to-noise ratio of the capped TiO2-NP/CB composites varied with the identity of the capping ligand. Hence, an array of TiO2-NP/CB composites, with each film having a compositionally different carboxylate capping ligand, provided good vapor discrimination and quantification when exposed to a series of organic vapors. Principal components analysis of the relative differential resistance response of the sensor array revealed a clear clustering of the response for each analyte tested. This approach expands the options for composite-based chemiresistive vapor sensing, from use of organic monomeric or polymeric sorbent phases, to use of electrically insulating capped inorganic NPs as the nonconductive phase of chemiresistive composite vapor sensors.

Original languageEnglish
Pages (from-to)17-22
Number of pages6
JournalSensors and Actuators, B: Chemical
Issue number1
Publication statusPublished - Nov 15 2011


  • Carbon black composites
  • Electronic nose
  • Principal components analysis (PCA)
  • Titanium (IV) dioxide nanoparticles

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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