Synthesis and hydrogen gas sensing properties of pure NiS and Au-coated NiS

• Published in: 2012 IEEE Sensors pp. 1 - 4
• Main Authors: Linganiso, E. C., Mwakikunga, B. W., Sone, B. T., Mhlanga, S. D., Coville, N. J., Maaza, M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.10.2012
• Subjects: Gold; Hydrogen; Nanostructures; Resistance; Temperature sensors
• ISBN: 9781457717666; 1457717662
• ISSN: 1930-0395; 2168-9229
• DOI: 10.1109/ICSENS.2012.6411342

NiS nanostructures were synthesized using a microwave-assisted wet chemical hydrothermal technique. XRD analysis of the product obtained after washing the product and drying it at 90°C for 6 hours confirmed that α-NiS and β-NiS phases were formed. Au nanostructures were deposited on the surface of the NiS product via a microwave-assisted impregnation technique. H 2 gas sensitivity of NiS or Au/NiS was measured by recording a change in resistance of the sample with time in the presence and absence of the analyte gas, at 300°C. The materials were exposed to H 2 gas of different flow rates relative to N 2 gas flow. Fast response due to reduced H 2 gas flow over similar time intervals was observed which was suggestive of a reliable sensing behavior of the Au/NiS material. Post sensing phase analysis of the materials showed that NiS phase was reduced to the more stable phase of nickel sulfide (Ni 3 S 2 ).