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Hydrogen Oxidation-Mediated Current Discharge in Mesoporous Pt/TiO2 Nanocomposite

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journal contribution
posted on 18.12.2017 by Nathan J. Ray, Eduard G. Karpov
Here we report on direct evidence of a correlation between hydrogen-to-water oxidation on mesoporous Pt/TiO2 nanocomposites at room temperature and the conversion of surface-released chemical energy into a stationary electrical current. The Pt phase of this heterojunction device is an electrically continuous 15 nm thick mesh deposited onto a mesoporous TiO2 substrate fabricated with a plasma electrolytic oxidation process. The H2O turnover frequency approaches an asymptotic value associated with the saturation of the Pt/TiO2 interface as the concentration of hydrogen gas is increased. In situ measurements of the reaction-induced current concurrently with mass spectrometry measurements illuminate the polarity switch of the reaction current (from thermionic emission to a reverse steady-state flow) simultaneously with the production of water. Furthermore, a concentration-dependent value of 5 min is measured as the time constant for the adsorption of the initial addition of H2 and H2O formation and desorption.

Funding

This research was supported by the Center for Nanoscale Materials at Argonne National Laboratory. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

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Publisher Statement

Post print version of article may differ from published version. The definitive version is available through American Chemical Society at DOI:10.1021/acsami.6b11794

Publisher

American Chemical Society

issn

19448244

Issue date

23/11/2016

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