Šoltić, Monika; Klencsár, Zoltán; Dražič, Goran; Gotić, Marijan; Ivanda, Mile; Baran, Nikola (2024) Hydrogen gas sensing properties of mechanochemically dispersed platinum on α-Fe2O3 support. Sensors and Actuators A: Physical, 376 . ISSN 0924-4247
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Abstract
We investigated the H-2 sensing performance of pure alpha-Fe2O3 and Pt/alpha-Fe2O3 samples, where platinum was mechanochemically dispersed on reducible alpha-Fe2O3 supports by ball miling, at concentrations of 1, 3, 5 and 10 mol%. The hematite nature of the supports was confirmed by Mossbauer spectroscopy. Raman spectroscopy reveals signature lines of hematite as well as ''forbidden'' longitudinal optical modes indicating stress-induced asymmetry. Scanning and transmission electron micrographs show nanometer-sized Pt dots dispersed on loosely aggregated alpha-Fe2O3 crystallites with a diameter of (sic) 50 nm. Pt/ alpha-Fe2O3 powder was suspended in ethanol and drop-cast onto glass substrates with interdigitated electrodes. The samples were exposed to H-2 concentrations from 0 - 500 ppm at different temperatures from 293 K to 553 K. The electrical resistance of the samples with Pt decreased with increasing H-2 concentration even at room temperature, indicating sensitivity to H-2. The sensitivity and response time improved significantly at higher temperatures. The response and response time at 100 ppm H-2 ranged from similar to-10% and (sic)75 s at 298 K to similar to-50% and similar to 5 s at 553 K. No dependence of the sensitivity on the Pt loading was observed, but a Pt loading of at least 1 mol% is essential for the sensors to function. The behavior of the sensors suggests a reversible sensing mechanism based on the Pt-mediated interaction of H-2 with adsorbed oxygen. These results indicate a possible use of Pt/alpha-Fe2O3 as a sensor for H-2 with a linear response at concentrations of 0-100 ppm and encourage further research.
| Item Type: | Article | ||||||||
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| Uncontrolled Keywords: | Hydrogen gas; sensing properties; platinum | ||||||||
| Subjects: | NATURAL SCIENCES > Chemistry | ||||||||
| Divisions: | Division of Materials Physics | ||||||||
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| Depositing User: | Sanja Jurković | ||||||||
| Date Deposited: | 29 Jul 2024 10:29 | ||||||||
| URI: | http://fulir.irb.hr/id/eprint/8973 | ||||||||
| DOI: | 10.1016/j.sna.2024.115539 |
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