Attenuated total reflection infrared spectroscopy for studying adsorbates on planar model catalysts: CO adsorption on silica supported Rh nanoparticles

Abstract

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. A sensitive method is presented for studying adsorption of gaseous species on metal surfaces in vacuum by attenuated total internal reflection Fourier transform infrared spectroscopy ͑ATR͒. The method is illustrated by CO adsorption experiments on silica supported Rh nanoparticles. An experimental setup and a procedure are described in detail to obtain a sensitivity of reflectance change of ϳ5 ϫ 10 −5 absorbance units. Here, a silicon ATR crystal with a 50 nm layer of hydroxylated silica acts as the support for the Rh nanoparticles. These particles are easily prepared by spincoat impregnation from a RhCl 3 solution followed by H 2 reduction. X-ray photoelectron spectroscopy before and after reduction shows that rhodium is reduced to Rh 0 and that all chlorine is removed. Atomic force microscope images the distribution of the particles, which are 3 -4 nm in height. When the crystal is exposed to pressures up to 1 mbar of CO, a gas which is inert to the silica support, the stretch vibration of linearly adsorbed CO on the Rh nanoparticles is detected at 2023 cm −1 , while no bridged CO or geminal dicarbonyl species can be distinguished. The minimum detectable coverage is estimated ϳ0.005 CO per nm 2 substrate area or ϳ5 ϫ 10 −4 ML.

Unusual Carbonyl−Nitrosyl Complexes of Rh2+ in Rh−ZSM-5: A Combined FTIR Spectroscopy and Computational Study

“…Infrared Spectra of Co-adsorb ed 12 CO and 14 NO. Adsorption of CO on the Rh−ZSM-5 sample, followed by evacuation, results in the appearance of bands, characterizing the Rh + (CO) 2 (2114 and 2048 cm -1 ) ,,,− and Rh 2+ (CO) 2 (2176 and 2142 cm -1 ) 1 species (Figure , spectrum a). A weak band at 2097 cm -1 is also discernible and assigned to the Rh + ( 12 CO)( 13 CO) species formed as a result of the natural 13 C abundance.…”

Cation Bridging Studied by Specular Neutron Reflection

“…In cases where the solution concentration is low and the adsorbed film is comparatively densely packed the observed spectrum is dominated by the adsorbed layer. 46,47 Hence, this approach is ideally suited to the study of adsorbed layers under water where the strong water adsorption bands preclude other IR spectroscopic techniques.…”

“…For a silicon IRE and an angle of incidence of 60° the penetration depth is typically of the order of 3–4 μm; ATR-IR data therefore contain a contribution from both the bulk solution and the adsorbed layer. In cases where the solution concentration is low and the adsorbed film is comparatively densely packed the observed spectrum is dominated by the adsorbed layer. , Hence, this approach is ideally suited to the study of adsorbed layers under water where the strong water adsorption bands preclude other IR spectroscopic techniques.…”

Operando attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy for water splitting

“…It is used for a wide range of chemical (e.g. [23,[30][31][32]), biological (e.g. [26,[33][34][35]), and pharmacological (e.g.…”