| Autor: |
Kumarage GWC; SENSOR Laboratory, Department of Information Engineering, University of Brescia, Via Valotti 9, 25133 Brescia, Italy.; Department of Physics and Electronics, Faculty of Science, University of Kelaniya, Kelaniya 11600, Sri Lanka., Panamaldeniya SA; Postgraduate Institute of Science, University of Peradeniya, Peradeniya 20400, Sri Lanka.; Department of Physics, Faculty of Science, University of Peradeniya, Peradeniya 20400, Sri Lanka., Maraloiu VA; Laboratory of Atomic Structures and Defects in Advanced Materials, National Institute of Materials Physics, Atomistilor Str. 405 A, 077125 Magurele, Romania., Dassanayake BS; Department of Physics, Faculty of Science, University of Peradeniya, Peradeniya 20400, Sri Lanka., Gunawardhana N; Research and International Affairs, Sri Lanka Technological Campus, Padukka 10500, Sri Lanka., Comini E; SENSOR Laboratory, Department of Information Engineering, University of Brescia, Via Valotti 9, 25133 Brescia, Italy. |
| Abstrakt: |
Pseudohexagonal Nb 2 O 5 microcolumns spanning a size range of 50 to 610 nm were synthesized utilizing a cost-effective hydrothermal process (maintained at 180 °C for 30 min), followed by a subsequent calcination step at 500 °C for 3 h. Raman spectroscopy analysis unveiled three distinct reflection peaks at 220.04 cm -1 , 602.01 cm -1 , and 735.3 cm -1 , indicative of the pseudohexagonal crystal lattice of Nb 2 O 5 . The HRTEM characterization confirmed the inter-lattice distance of 1.8 Å for the 110 plain and 3.17 Å for the 100 plain. The conductometry sensors were fabricated by drop-casting a dispersion of Nb 2 O 5 microcolumns, in ethanol, on Pt electrodes. The fabricated sensors exhibited excellent selectivity in detecting C 2 H 5 OH (ΔG/G = 2.51 for 10 ppm C 2 H 5 OH) when compared to a variety of tested gases, including CO, CO 2 , NO 2 , H 2 , H 2 S, and C 3 H 6 O. The optimal operating temperature for this selective detection was determined to be 500 °C in a dry air environment. Moreover, the sensors demonstrated exceptional repeatability over the course of three testing cycles and displayed strong humidity resistance, even when exposed to 90% relative humidity. This excellent humidity resistance gas sensing property can be attributed to their nanoporous nature and elevated operating temperature. |
