Publication detail

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

BANNOV, A. JAŠEK, O. PRÁŠEK, J. BURŠÍK, J. ZAJÍČKOVÁ, L.

Original Title

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

Type

journal article in Web of Science

Language

English

Original Abstract

The ammonia adsorption on the nanostructured carbon thin film was significantly influenced by the choice of deposition temperature and deposition time of thin film synthesis. The thin films were prepared on Si/SiO2 substrates by chemical vapour deposition in Ar/C2H2 gas mixture using iron catalytic nanoparticles. The analysis of the grown layer by the scanning and transmission electron microscopy showed the transition from long multiwalled nanotubes (MWCNTs) to bamboo-like hollow carbon nanofiber structure with the decrease of the deposition temperature from 700 to 600°C. Further, the material was analyzed by energy-dispersive X-ray spectroscopy and Raman spectroscopy confirmed the transition from graphitic sp ² structure to highly defective structure at lower deposition temperature. The resistance of the prepared layer strongly depends on deposition temperature ( Td ) and deposition time ( td ). High resistance layer, 38.6 kΩ, was formed at Td 600°C and td 10 min, while at Td 700°C and td 60 min, the resistance decreased to 860 ohms. Such behaviour is consistent with MWCNTs being responsible for the formation of the conductive network. Such system was studied using chemiresistor ammonia gas sensor configuration. The sensor resistance increased when exposed to ammonia in all the cases, but their response varied considerably. A decrease in deposition time, from 60 to 10 min, and the deposition temperature, from 700 to 600°C, led to the 10-fold increase in the sensor response. The measurements carried out at room temperature showed the higher sensor response than the measurements carried out at 200°C. This behaviour can be explained by the change in adsorption-desorption equilibrium at different temperatures. Analysis of dependence of the sensor response on the ammonia concentration proved that the underlying resistance change mechanism is chemisorption of ammonia molecules on the carbon network corresponding to the Langmuir isotherm.

Keywords

ammonia; nanofibrous carbon; MWCNTs; gas sensor

Authors

BANNOV, A.; JAŠEK, O.; PRÁŠEK, J.; BURŠÍK, J.; ZAJÍČKOVÁ, L.

Released

17. 9. 2018

Publisher

Hindawi

ISBN

1687-7268

Periodical

Journal of Sensors

Year of study

2018

Number

7497619

State

United States of America

Pages from

1

Pages to

14

Pages count

14

URL

http://dx.doi.org/10.1155/2018/7497619

Full text in the Digital Library

http://hdl.handle.net/11012/193261

BibTex

@article{BUT150641,
  author="Alexander G. {Bannov} and Ondřej {Jašek} and Jan {Prášek} and Jiří {Buršík} and Lenka {Zajíčková}",
  title="Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films",
  journal="Journal of Sensors",
  year="2018",
  volume="2018",
  number="7497619",
  pages="1--14",
  doi="10.1155/2018/7497619",
  issn="1687-7268",
  url="http://dx.doi.org/10.1155/2018/7497619"
}