Simonkolleite nano-platelets: Synthesis and temperature effect on hydrogen gas sensing properties

• Published in: Applied surface science 2012-08, Vol.258 (20), p.7839-7843
• Main Authors: Sithole, J., Ngom, B.D., Khamlich, S., Manikanadan, E., Manyala, N., Saboungi, M.L., Knoessen, D., Nemutudi, R., Maaza, M.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Gas sensors; Hydrothermal; Morphology; Nano-particles; Nanocomposites; Nanomaterials; Nanostructure; Photonics and gas sensing; Physics; Scanning electron microscopy; Simonkolleite; X-rays; Zinc; Zinc oxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.04.073

► The crystallinity indicates that the plate-like Zn5(OH)8Cl2·H2O possessed a smooth surface. ► The fast responses and high sensitivity due to high polarity and/or porosity in plate-like structure of simonkolleite sample. ► The sensitivity ΔR/R of our sensor is attractive for further investigation for practical H2 sensor applications. ► The simonkolleite Zn5(OH)8Cl2·H2O nano-platelets revealed a significant and singular H2 gas sensing characteristics. In this work, the new refined mineral platelets-like morphology of simonkolleite based particles described by Shemetzer et al. (1985) were synthesized in zinc nitrate aqueous solution by a moderate solution process. The morphological and structural properties of the platelets-like Zn5(OH)8Cl2·H2O were characterized by scanning electron microscope energy dispersed X-ray spectroscopy, transmission electron microscope, powder X-ray diffraction and selected area electron diffraction as well as attenuated total reflection infrared spectroscopy. The morphology as well as the size in both basal and transversal directions of the simonkolleite Zn5(OH)8Cl2·H2O nano/micro crystals was found to be significantly depending on the specific concentration of 0.1M of Zn2+/Cl− ions in the precursor solution. The simonkolleite Zn5(OH)8Cl2·H2O nano-platelets revealed a significant and singular H2 gas sensing characteristics. The operating temperature was found to play a key role on the sensing properties of simonkolleite. The effect of temperature on the simonkolleite sample as a hydrogen gas sensor was studied by recording the change in resistivity of the film in presence of the test gas. The results on the sensitivity and response time as per comparison to earlier reported ZnO based sensors are indicated and discussed.