Highly sensitive silicon microreactor for catalyst testing

Journal Article · Tue Dec 15 00:00:00 EST 2009 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3270191· OSTI ID:22051124

Henriksen, Toke R; Hansen, Ole ^[1]; Olsen, Jakob L; Vesborg, Peter; Chorkendorff, Ib ^[2]

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1. Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark)
2. Department of Physics, Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, Building 312, DK-2800 Kgs. Lyngby (Denmark)

A novel microfabricated chemical reactor for highly sensitive measurements of catalytic activity and surface kinetics is presented. The reactor is fabricated in a silicon chip and is intended for gas-phase reactions at pressures ranging from 0.1 to 5.0 bar. A high sensitivity is obtained by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally. A corresponding theoretical model is presented, and the gas flow through an on-chip flow-limiting capillary is predicted to be in the intermediate regime. The experimental data for the gas flow are found to be in good agreement with the theoretical model. At typical experimental conditions, the total gas flow through the reaction zone is around 3x10{sup 14} molecules s{sup -1}, corresponding to a gas residence time in the reaction zone of about 11 s. To demonstrate the operation of the microreactor, CO oxidation on low-area platinum thin film circles is employed as a test reaction. Using temperature ramping, it is found that platinum catalysts with areas as small as 15 {mu}m{sup 2} are conveniently characterized with the device.

• OSTI ID: 22051124
• Journal Information: Review of Scientific Instruments, Vol. 80, Issue 12; Other Information: (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
CARBON MONOXIDE
CATALYSIS
CATALYSTS
CHEMICAL ANALYSIS
CHEMICAL REACTORS
GAS FLOW
MASS SPECTROSCOPY
MATERIALS TESTING
OPERATION
OXIDATION
PLATINUM
REACTION KINETICS
SEMICONDUCTOR MATERIALS
SENSITIVITY
SILICON
SURFACE AREA
THIN FILMS