title: Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material.
abstract: Graphite oxide has been investigated as a possible room-temperature chemiresistive sensor of ammonia in a gas phase. Graphite oxide was synthesized from high purity graphite using the modified Hummers method. The graphite oxide sample was investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry. Sensing properties were tested in a wide range of ammonia concentrations in air (10-1000 ppm) and under different relative humidity levels (3%-65%). It was concluded that the graphite oxide-based sensor possessed a good response to NH₃ in dry synthetic air (ΔR/R₀ ranged from 2.5% to 7.4% for concentrations of 100-500 ppm and 3% relative humidity) with negligible cross-sensitivity towards H₂ and CH₄. It was determined that the sensor recovery rate was improved with ammonia concentration growth. Increasing the ambient relative humidity led to an increase of the sensor response. The highest response of 22.2% for 100 ppm of ammonia was achieved at a 65% relative humidity level.
authors.affiliation: Department of Chemistry and Chemical Technology, Novosibirsk State Technical University, K. Marx 20, RU-630073 Novosibirsk, Russia. bannov_a@mail.ru.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Bannov
authors.affiliation: SIX Research Centre, Brno University of Technology, Technická 10, CZ-61600 Brno, Czech Republic. prasek@feec.vutbr.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Prášek
authors.affiliation: Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic. jasek@physics.muni.cz.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Jašek
authors.affiliation: Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic. lenkaz@physics.muni.cz.|RG Plasma Technologies, CEITEC-Central European Institute of Technology, Masaryk University, Purkyňova 123, CZ-61200 Brno, Czech Republic. lenkaz@physics.muni.cz.
authors.forename: Lenka
authors.initials: L
authors.lastname: Zajíčková
keywords: ammonia; chemiresistive gas sensor; graphite oxide; sensitivity