CO gas-sensing properties of CuO-TiN and CuO-TiO2 prepared via an oxidizing process of a Cu-TiN composite synthesized by a mechanically induced gas-solid reaction
Abstract
A Cu-TiN composite powder was synthesized by ball milling a Ti2Cu alloy for 25 h in an N2 pressurized atmosphere for use in CuO-TiN and CuO-TiO2 p-type sensing materials. The sensing materials were prepared via a two-step oxidizing process following an investigation of their CO gas-sensing properties. The resistances of both sensing materials increased as CO was introduced, which is typical for a p-type semiconductor at temperature higher than 200 °C. It was found that the CuO-TiN powder shows a better response above 200 °C when compared to the CuO-TiO2 powder. The highest response shown by CuO-TiN was 3.18, while CuO-TiO2 shows a response of 2.20 for 1000 ppm of CO gas at 250 °C. It is believed that the lower responses of CuO-TiO2 at temperature higher than 200 °C was due to the falloff of p-type resistances by simultaneous operation of p- and n-type semiconductors in the presence of CO gas.
- Publication:
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Metals and Materials International
- Pub Date:
- March 2014
- DOI:
- 10.1007/s12540-014-2027-4
- Bibcode:
- 2014MMI....20..323L
- Keywords:
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- composites;
- nanostructured materials;
- mechanical alloying/milling;
- CuO-TiN sensor material;
- p-type semiconductor