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Keywords:

  • chromium titanium oxide;
  • FTIR spectroscopy;
  • gas sensors;
  • Raman spectroscopy;
  • XRD

Abstract

Titanium substituted chromium oxide (Cr2 − xTixO3 + z, CTO) has gained increasing interest concerning gas sensing applications. CTO is prepared by synthesis of chromium oxide and titanium oxide. Different techniques for verification of successful synthesis of CTO have been investigated. Solid state Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were performed in addition to the common analysis via X-ray diffraction (XRD). The spectroscopic methods offer a fast, qualitative verification of a complete synthesis. CTO was synthesized in a high temperature sintering step, and powders and dispersions of CTO were prepared. A high energy grinding process leads to the required particle size reduction. The size distribution and crystallite size of the CTO particles were measured. Furthermore morphology and surface coverage analysis on novel type gas-sensing CTO layers, deposited via inkjet technology, were performed and specific adsorption energies of nitrogen dioxide on printed CTO layers were derived. High porosity with sub-micron particles was shown to be characteristic for the layers, resulting in a highly sensitive gas-sensing behavior, with 500 ppb of nitrogen dioxide being clearly detectable.