Ultrahigh vacuum compatible all-glass high pressure reaction cell for accurate and reproducible measurement of small reaction rates

Reichl, W.; Rosina, G.; Rupprechter, Günther; Zimmermann, C.; Hayek, K.

doi:10.1063/1.1150486

Cited by 28 publications

(18 citation statements)

References 20 publications

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“…Preparation and characterization of the model catalysts were performed under ultrahigh vacuum conditions in an experimental setup described before [11]. It consists of a conventional UHV chamber with a long travel z-manipulator and a small-volume Pyrex glass reactor (52 ml) attached to the outside of the chamber and accessible via a sample transfer port.…”

Section: Apparatusmentioning

confidence: 99%

Catalytic Oxidation of Ethene on Polycrystalline Palladium: Influence of the Oxidation State of the Surface

et al. 2005

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The partial and total oxidation of ethene was studied on clean and oxidized polycrystalline Pd in a UHV high-pressure cell. The model catalyst was prepared under UHV conditions and characterized by thermal desorption and Auger and Raman spectroscopy. Starting from either a Pd or PdO surface, reaction to CO 2 is the predominant pathway, and acetic acid is the main byproduct between 453 and 523 K. The route to partially oxidized products, in particular acetic acid, is more favoured on the PdO surface, while on Pd metal acetic acid is formed at lower temperatures than on PdO. On stoichiometric PdO activation for both partial and total oxidation occurs during an induction period, until under working conditions Pd metal, PdO, ÔPdC x ' and isolated defects are coexistent on the surface. The presence of an extended metal surface favours the follow-up oxidation of byproducts, while the presence of PdO stabilizes acetic acid far beyond 473 K.

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Section: Apparatusmentioning

confidence: 99%

Catalytic Oxidation of Ethene on Polycrystalline Palladium: Influence of the Oxidation State of the Surface

et al. 2005

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“…The first setup (for high-pressure kinetic studies) is located at Innsbruck University [27], the second one (for high-pressure in-situ XPS) at the HZB/BESSY II synchrotron facility (Berlin, Germany) [28], and the third one (for in-situ PM-IRAS) at Vienna University of Technology [29]. A detailed description of all three systems is given in the supporting information section of [14].…”

Section: Methodsmentioning

confidence: 99%

“…The main strength of the all-glass high-pressure cell, as described in detail in [27], is that any heated metal parts coming into contact with the respective reaction gas mixture are avoided, which is of paramount importance when measuring reaction rates on the model catalyst surfaces which exhibit only a small surface area of a few cm 2 . Therefore, also blind reaction runs under the exactly identical reaction conditions are regularly performed to ensure the "intrinsic inactivity" of our setup.…”

Section: Innsbruck Experimental Setupmentioning

confidence: 99%

“…The UHV system with attached high-pressure reaction cell [27] is designed for catalytic studies up to 1 bar on a larger piece of 2 cm × 2 cm polycrystalline Pd foil, allowing us to detect reaction products and even minor intermediates with high sensitivity, either by discontinuous sample injection into the gas chromatography-mass spectrometry (GC-MS) setup (HP G1800A) or by direct online MS analysis of the reaction mixture via a capillary leak into the GC/MS detector. The system consists of an UHV chamber with a long-travel Z-manipulator and a small-volume Pyrex glass reactor (52 ml, no hot metal components) attached to the outside of the UHV chamber and accessible via a sample transfer port.…”

Section: Innsbruck Experimental Setupmentioning

confidence: 99%

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Steam reforming of methanol on PdZn near-surface alloys on Pd(1 1 1) and Pd foil studied by in-situ XPS, LEIS and PM-IRAS

Rameshan

Weilach

Stadlmayr

et al. 2010

Journal of Catalysis

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The CO2-selectivity in methanol steam reforming was investigated for a "multilayer" PdZn 1:1 surface alloy (thickness of ~1.3 nm) and for a subsurface-Zn diluted "monolayer" PdZn surface alloy, both exhibiting a 1:1 composition in the surface layer. Despite having almost the same surface layer stoichiometry, these two types of near-surface alloys exhibit different corrugations and electronic structures. The CO2-selective multilayer alloy features a lowered density of states close to the Fermi edge and surface ensembles of PdZn exhibiting a "Zn-up/Pd-down" corrugation, acting as bifunctional active sites both for reversible water activation as ZnOH and for reaction of methanol (via formaldehyde + ZnOH) toward CO2. The thermochemical stability limit of the multilayer alloy at around 573 K was determined in-situ at elevated pressures of water, methanol and CO, applying in-situ XPS, PM-IRAS spectroscopy, LEIS and AES. Above 573 K, the coordination of the surface 1:1 PdZn layer with subsurfaceZn gradually decreased by bulk diffusion of Zn "escaping" from the second and deeper layers, resulting in a transition from the CO2-selective PdZn "multilayer" state to the unselective "monolayer" state, which only catalyses methanol dehydrogenation to CO.

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“…The quartz-to-metal seal is welded to a stainless steel cylinder which is the main part of the transfer unit. The transfer unit itself and its mechanism is described in detail in reference 16 , section II C.…”

Section: B Uhv Chambermentioning

confidence: 99%

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

Mayr

Rameshan

Klötzer

et al. 2014

Review of Scientific Instruments

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An ultra-high vacuum (UHV) setup for "real" and "inverse" model catalyst preparation, depth-resolved near-surface spectroscopic characterization and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the allquartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in-situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy (AES) and low-energy ion scattering (LEIS) measurements. Due the dedicated geometry of the X-ray gun (54.7°, "magic angle") and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depth, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained.To demonstrate the capability of the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming (MSR) on PdGa and PdZn near-surface intermetallic phases (NSIP) are shown.3

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Ultrahigh vacuum compatible all-glass high pressure reaction cell for accurate and reproducible measurement of small reaction rates

Cited by 28 publications

References 20 publications

Catalytic Oxidation of Ethene on Polycrystalline Palladium: Influence of the Oxidation State of the Surface

Catalytic Oxidation of Ethene on Polycrystalline Palladium: Influence of the Oxidation State of the Surface

Steam reforming of methanol on PdZn near-surface alloys on Pd(1 1 1) and Pd foil studied by in-situ XPS, LEIS and PM-IRAS

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

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