A micro-structured quartz reactor for kinetic and in situ spectroscopic studies in heterogeneous catalysis☆

Beato, Pablo; Kraehnert, Ralph; Engelschalt, S.; Frank, Thomas; Schlögl, Robert

doi:10.1016/j.cej.2007.07.011

Cited by 9 publications

(5 citation statements)

References 10 publications

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“…Miniaturized reaction systems play an increasing role in both in situ spectroscopic studies [1][2][3][4] and technical scale catalysis (microreactor arrays; cf. [5,6]).…”

Section: Introductionmentioning

confidence: 99%

Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

et al. 2009

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The catalytic partial oxidation of methane (CPO) over flame-made 2.5%Rh-2.5%Pt/Al 2 O 3 and 2.5%Rh/Al 2 O 3 in 6%CH 4 /3%O 2 /He shows the potential of in situ studies using miniaturized fixed-bed reactors, the importance of spatially resolved studies and its combination with infrared thermography and on-line mass spectrometry. This experimental strategy allowed collecting data on the structure of the noble metal (oxidation state) and the temperature along the catalyst bed. The reaction was investigated in a fixed-bed quartz microreactor (1-1.5 mm diameter) following the catalytic performance by on-line gas mass spectrometry (MS). Above the ignition temperature of the catalytic partial oxidation of methane (310-330°C), a zone with oxidized noble metals was observed in the inlet region of the catalyst bed, accompanied by a characteristic hot spot (over-temperature up to 150°C), while reduced noble metal species became dominant towards the outlet of the bed. The position of both the gradient in oxidation state and the hot spot were strongly dependent on the furnace temperature and the gas flow (residence time). Heating as well as a higher flow rate caused a migration of the transition zone of the oxidation state/maximum in temperature towards the inlet. At the same time the hydrogen concentration in the reactor effluent increased. In contrast, at low temperatures a movement of the transition zone towards the outlet was observed at increasing flux, except if the self-heating by the exothermic methane oxidation was too strong. The results indicate that in the oxidized zone mainly combustion of methane occurs, whereas in the reduced part direct partial oxidation and reforming reactions prevail. The results demonstrate how spatially resolved spectroscopy can help in understanding catalytic reactions involving different reaction zones and gradients even in micro scale fixed-bed reactors.

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“…Miniaturized reaction systems play an increasing role in both in situ spectroscopic studies [1][2][3][4] and technical scale catalysis (microreactor arrays; cf. [5,6]).…”

Section: Introductionmentioning

confidence: 99%

Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

et al. 2009

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“…Existing studies have revealed that Raman microscopy can be conveniently integrated with microreactors for studying catalysts. ,, Cao et al , successfully showed that for gas-phase oxidation of methanol to formaldehyde over a silver catalyst sputter-coated in a silicon/glass microreactor, Raman microscopy could be used to identify the surface species on the catalyst, and the influence of the reaction temperature as well as water on the catalyst composition and performance can be well explained based on the obtained Raman spectra. However, for liquid-phase oxidation of benzyl alcohol by molecular oxygen on a (Au–Pd)/TiO 2 catalyst packed into another silicon/glass microreactor, the identification of the intermediate species on the catalyst surface via Raman microscopy was less successful mainly due to the strong interfering fluorescence signal.…”

Section: Integration Of Microreactors With Spectroscopic Detection Fo...mentioning

confidence: 99%

“…Beato et al 217 developed a modular microstructured quartz reactor with spin-coated Mo−V−W mixed oxide thin film catalyst and tested the microreactor with the gas-phase selective oxidation of propane. The reactor was placed under a Raman microscope in order to perform in situ Raman measurements.…”

Section: Integration Of Microreactors With Spectroscopic Detection Fo...mentioning

confidence: 99%

Integration of Microreactors with Spectroscopic Detection for Online Reaction Monitoring and Catalyst Characterization

Yue

Schouten

Nijhuis

2012

Ind. Eng. Chem. Res.

125

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Microreactor technology has gained significant popularity in the chemical and process industry in the past decade. The development of microreactors either as innovative production units for chemical synthesis or as promising laboratory tools for reaction and kinetic studies relies highly on the capability of performing online analyses, which opens great opportunities for the integration of spectroscopic detection techniques. This paper gives an overview of the state-of-the-art in the combination of microreactors with spectroscopic analyses for online reaction monitoring and catalyst characterization. In this upcoming field, many studies have been carried out combining fluorescence, ultraviolet−visible, infrared, Raman, X-ray, and nuclear magnetic resonance spectroscopy. Current research progress is reviewed, with emphasis on the existing integration schemes and selected application examples that demonstrate the potential of online spectroscopic detection for rapid microreactor process analysis and optimization. An outlook on the future development in this area is also presented.

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“…The use of microfluidic and microfabricated reactors which can offer accurate control of process conditions, homogeneous temperature distribution and a distinct flow pattern, has been reported for operando spectroscopic studies under realistic reaction conditions. [39][40][41][42][43][44][45][46][47] Such microreactors are valuable and compact tools for spectroscopic studies 24,39 including Raman, 40,48,49 IR, [50][51][52][53] X-ray diffraction (XRD) 45,54,55 and XAS. 42,45,55,56 Among such reactors, silicon microfabricated reactors have unique advantages due to their high thermal conductivity, chemical inertness and mechanical stability.…”

Section: Introductionmentioning

confidence: 99%

Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

Venezia

Cao

Matam

et al. 2020

Catal. Sci. Technol.

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A micro-structured quartz reactor for kinetic and in situ spectroscopic studies in heterogeneous catalysis☆

Cited by 9 publications

References 10 publications

Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

Integration of Microreactors with Spectroscopic Detection for Online Reaction Monitoring and Catalyst Characterization

Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

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