Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy
Max-Planck-Institut für Kohlenforschung, Department of Heterogeneous Catalysis, 45470 Mülheim an der Ruhr, Germany
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Molecules 2019, 24(17), 3199; https://doi.org/10.3390/molecules24173199
Received: 13 August 2019
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Revised: 26 August 2019
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Accepted: 29 August 2019
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Published: 3 September 2019
(This article belongs to the Special Issue Zeolites and Related Porous Materials: Design, Synthesis, and Applications)
We report a varying temperature infrared spectroscopic (VTIR) study with partial deuterium isotopic exchange as a method for characterizing proton mobility in acidic materials. This VTIR technique permits the estimation of activation energies for proton diffusion. Different acidic materials comprising classical proton-conducting materials, such as transition metal phosphates and sulfonated solids, as well as different zeolites, are tested with this new method. The applicability of the method is thus extended to a vast library of materials. Its underlying principles and assumptions are clearly presented herein. Depending on the temperature ranges, different activation energies for proton transfer are observed irrespective of the different materials. In addition to the well-studied transition metal phosphates, Si-rich zeolites appear to be promising proton-transfer materials (with Eact < 40 kJ mol−1) for application in high-temperature (>150 °C) PEM fuel cells. They significantly outperform Nafion and sulfonated silica, which exhibit higher activation energies with Eact ~ 50 and 120 kJ mol−1, respectively.
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Keywords:
pProton-conducting materials; VTIR; acidic materials; zeolites
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MDPI and ACS Style
Losch, P.; Joshi, H.; Stegmann, N.; Vozniuk, O.; Schmidt, W. Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy. Molecules 2019, 24, 3199. https://doi.org/10.3390/molecules24173199
AMA Style
Losch P, Joshi H, Stegmann N, Vozniuk O, Schmidt W. Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy. Molecules. 2019; 24(17):3199. https://doi.org/10.3390/molecules24173199
Chicago/Turabian StyleLosch, Pit, Hrishikesh Joshi, Niklas Stegmann, Olena Vozniuk, and Wolfgang Schmidt. 2019. "Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy" Molecules 24, no. 17: 3199. https://doi.org/10.3390/molecules24173199
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