Bannov AG, Prášek J, Jašek O, Zajíčková L. Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material.
SENSORS 2017;
17:s17020320. [PMID:
28208762 PMCID:
PMC5336062 DOI:
10.3390/s17020320]
[Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/02/2017] [Accepted: 02/06/2017] [Indexed: 11/16/2022]
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.
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