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Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control
Author(s) -
Doll Theodor,
VelascoVelez Juan J.,
Rosenthal Dirk,
Avila Jonathan,
Fuenzalida Victor
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201201013
Subject(s) - x ray photoelectron spectroscopy , nanometre , adsorption , semiconductor , nanotechnology , catalysis , electric field , chemical physics , materials science , doping , electronic structure , chemistry , chemical engineering , optoelectronics , computational chemistry , organic chemistry , physics , composite material , quantum mechanics , engineering
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 conductivity analysis on nanometre‐thick semiconductor films on buried control electrodes is reported. For the SnO 2 /NO 2 model system, NO 3 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.