Berlin 2012 – wissenschaftliches Programm

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 2: Desorption

VA 2.2: Vortrag

Montag, 26. März 2012, 14:20–14:40, HFT-FT 131

AP-TDS characterization of CO₂ methanation catalysts — •Matthias Städter and Dieter Schmeißer — Brandenburg University of Technology, Cottbus, Germany

Development of new catalysts and their characterization by TDS (thermal desorption spectroscopy) is used in a wide field of applications. In our group we focus on catalysts usable to convert CO₂ towards methane by the Sabatier reaction (CO₂ + 4H₂ → CH₄ + 2H₂O at 375^∘C). For measuring large numbers of samples we designed an AP-TDS (ambient pressure TDS) chamber where various desorption experiments can be performed without bringing the catalyst into vacuum. The well-defined reaction chamber, in terms of temperature, pressure and gas composition (Ar atmosphere), is separated by a pin hole (∅ = 6 µ m) from an external UHV chamber. Evolving species and their composition are monitored by a mass spectrometer attached to the UHV chamber. Our first measurement results on commercially available NiO/SiO₂ and Ru/Al₂O₃ based catalysts, with focus on the identification and enumeration of different adsorption sites for CO₂, will be presented. CO₂ saturated samples were heated from RT to 1100^∘C (heating rate β = 0.3 K/s) while measuring the evolution of the CO₂ content. Our measurements show large numbers of different adsorption sites for NiO (200-750^∘C) whereas Ru shows only few different sites around 440^∘C. For both catalysts, most of the formerly adsorbed CO₂ remains at the surface (at 375^∘C) available for methanation.