کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5424330 | 1395820 | 2010 | 5 صفحه PDF | دانلود رایگان |
Specular reflectance FTIR study of carbon monoxide adsorbed on platinum is performed on Pt/SiO2/Au layered structures prepared by deposition of thin films on silicon (1Â 0Â 0) wafers. The layered structures consist of 5Â nm thick platinum films over SiO2 films of varying thicknesses with 50Â nm thick reflecting gold films underneath. Due to optical interference effects, the reflectance of each of these structures varies with the incident infrared wavelength and goes through a minimum at a wavelength that depends on the thickness of the SiO2 layer. The decrease in the reflectance R causes an effective increase in the ÎR/R value resulting in a large increase in the infrared absorption band intensity of linearly-adsorbed CO. The peak height changes with changing the SiO2 thickness in the structures and is greatest for the sample which has lowest reflectance near the absorption wavelength of CO (â¼2100Â cmâ1). This improvement in the ratio of FTIR signal to background reflectance can be very useful for probing low surface area model catalytic surfaces at atmospheric pressures and under reaction conditions. A spectrum of CO adsorbed on nanofabricated Pt nanowire catalysts on TiO2 support is also shown as an example of the sensitivity enhancement on layered structures.
Journal: Surface Science - Volume 604, Issue 2, 15 January 2010, Pages 79-83