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Erscheinungsjahr
- 2016 (3) (entfernen)
Dokumenttyp
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- Englisch (3)
Schlagworte
- Adsorbates (2)
- DRIFTS (2)
- Infrared spectroscopy (2)
- Platinum (2)
- Silica support (2)
- X-ray absorption spectroscopy (2)
- XANES (2)
- CO adsoprtion (1)
- CO adsorption (1)
- Characterization (1)
The adsorption behavior of Platinum nanoparticles was studied for the as-received catalyst (under inert gas), under hydrogen and CO atmosphere using our newly designed in-situ cell. X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiments were performed simultaneously with high data quality. Structural information and the type of adsorbate could be revealed via Extended X-ray Absorption Fine Structure (EXAFS) analysis, Δμ X-ray Absorption Near Edge Structure analysis (Δμ XANES) and in-situ DRIFTS. The as-received catalyst showed sub-surface oxygen and O(n-fold). Under CO atmosphere only CO(atop) was found. Reversible adsorbate induced changes of the Pt nanoparticle structure were derived from changes in the Pt-Pt coordination number and the corresponding bond distance. Under reducing conditions (H2, CO) a significant increase in both values occurred. Temperature dependent desorption of CO revealed a gradual shift from Pt-CO to Pt-O. Reoxidation was clearly assigned to strong metal support interaction from the SiO2 support.
The adsorption behavior of Platinum nanoparticles was studied for the as-received catalyst (under inert gas), under hydrogen and CO atmosphere using our newly designed in-situ cell. X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiments were performed simultaneously with high data quality. Structural information and the type of adsorbate could be revealed via Extended X-ray Absorption Fine Structure (EXAFS) analysis, Dl X-ray Absorption Near Edge Structure analysis (Dl XANES) and in-situ DRIFTS. The as-received catalyst showed sub-surface oxygen and O(n-fold). Under CO atmosphere only CO(atop) was found. Reversible adsorbate induced changes of the Pt nanoparticle structure were derived from changes in the PtAPt coordination number and the corresponding bond distance. Under reducing conditions (H2, CO) a significant increase in both values occurred. Temperature dependent desorption of CO revealed a gradual shift from PtACO to PtAO. Reoxidation was clearly assigned to strong metal support interaction from the SiO2 support.
We aim at preparing, characterising, and applying SURMOFs incorporating electro-active and -switchable mechanically interlocked molecules such as rotaxanes as the basis of functional devices.
Preparation and Positioning
Synthesis, purification and analytical characterization of electro-switchable rotaxanes suitable for SURMOF-formation as well as Layer-by-Layer assembly on surfaces.
Controlled deposition of electro-active SURMOFs and Layer-by-Layer self-assembled multilayers based on these switchable rotaxanes.
Construction of SURMOFs on micro-patterned surfaces.
Structural Characterisation and Physico-Chemical Properties
Electrochemical characterization of these rotaxanes in solution with cyclic voltammetry, chronoamperometry and impedance spectroscopy.
Surface characterization of SURMOFs and multilayers with XPS, NEXAFS, AFM, contact-angle measurements, transmission UV/Vis, ToF-SIMS and – in cooperation with partners from SPP – XRD.
Development of ToF-SIMS (also assisted by Principle Component Analysis of the fragment-ion data) as a method for imaging and depth-profiling.
Development of an appropriate electrochemical cell to perform cyclic voltammetry, chronoamperometry and impedance spectroscopy with SURMOFS and multilayers as working electrodes in a three-electrode cell.
Comparison of the structural and electrochemical properties of the redox-active unit in solution, multilayers and SURMOF focusing on the advantages of SURMOFs.
System Integration and Function Demonstration
Examination of the usability of the electroactive SURMOFS as optoelectronic switch or data storage device with a focus on the robustness of the system.
Usage of the SURMOFs as functional electrodes for electrochemical application.
Selective switching of ordered nanostructures to translate molecular motion to macroscopic property changes.