Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic-Surface Control
Author
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Doll, Theodor
Author
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Velasco Vélez, Juan J.
es_CL
Author
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Rosenthal, Dirk
es_CL
Author
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Avila, Jonathan
es_CL
Author
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Fuenzalida Escobar, Víctor
es_CL
Admission date
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2014-01-29T14:14:32Z
Available date
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2014-01-29T14:14:32Z
Publication date
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2013
Cita de ítem
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ChemPhysChem 2013, 14, 2505 – 2510
en_US
Identifier
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DOI: 10.1002/cphc.201201013
Identifier
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https://repositorio.uchile.cl/handle/2250/126324
General note
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Artículo de publicación ISI
en_US
Abstract
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Microchemical sensors and catalytic reactors make use of gases during adsorption in specific ways on selected materials. Fine-tuning is normally achieved by morphological control and material doping. The latter relates surface properties to the electronic structure of the bulk, and this suggests the possibility of electronic control. Although unusual for catalytic surfaces, such phenomena are sometimes reported for microsensors, but with little understanding of the underlying mechanisms. Herein, direct observation of the electroadsorptive effect by a combination of X-ray photoelectron spectroscopy and con-ductivity analysis on nanometre-thick semiconductor films on buried control electrodes is reported. For the SnO2/NO2 model system, NO3 surface species, which normally decay at the latest within minutes, can be kept stable for 1.5 h with a high coverage of 15% under appropriate electric fields. This includes uncharged states, too, and implies that nanoelectronic structures provide control over the predominant adsorbate conformation on exterior surfaces and thus opens the field for chemically reactive interfaces with in situ tunability.