Quasi-2D-nanoflakes of Co3O4: synthesis and chemoresistive response to vapors of compound studies
M.A. Solomatin1, F.S. Fedorov1, A.S. Varezhnikov1, D.A. Kolosov3, O.E. Glukhova3, A.G. Nasibulin2, V.V. Sysoev2
1 Yury Gagarin State Technical University of Saratov, Saratov, Russia,
2 Skolkovo Institute of Science and Technology, Moscow, Russia,
3 Saratov State University, Saratov, Russia
Abstract
In this work, quasi-two-dimensional cobalt oxide nanofleakes were obtained by electrochemical deposition. The synthesis was carried out in an aqueous electrolyte, 0.1 M Co (NO3) 2, by applying a potential of -1 V rel. Ag / AgCl sat. to Pt electrodes formed on a Si / SiO2 wafer. By selecting the deposition parameters (electrolyte composition and deposition time), it was possible to control the morphology and thickness of the oxide layer and, in particular, to achieve the characteristic structure of the deposited cobalt (II) hydroxide in the form of hierarchical hexagonal nanofleakes. After annealing in an air atmosphere at a temperature of 300 ° C, the material was transformed into cobalt (II, III) oxide while maintaining the original hierarchical structure. It was shown that sensors based on the obtained structures exhibit a high chemoresistive response, ~ 50-430% at 275 ° C, when interacting with vapors of various alcohols in a mixture with air at concentrations in the range of 1-10 ppm with a detection limit in the ppb range. The observed chemoresistive effect is associated with a change in the concentration of free charge carriers during the interaction of the oxide with organic compounds, and the sensitivity increases with an increase in the molecular weight of alcohol in the homologous series. This feature was confirmed by numerical calculations within the framework of the density functional theory.
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M. Solomatin
Yury Gagarin State Technical University of Saratov
Russia
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