Microreactor for studies of low surface area model catalysts made by electron-beam lithography

A flow reactor for evaluation of low surface area, model catalysts has been designed. The aim is to measure catalytic activity at atmospheric pressure on nanofabricated model catalysts, primarily made by the electron-beam lithography (EBL) technique. This is a challenge because of the low attainable active surface area on such model catalysts, due to the serial processing in EEL manufacturing. The interest in using EBL-nanofabricated model catalysts derives from the high level of control over the catalyst geometry that is obtainable. In order to evaluate the performance of the reactor for such catalysts, two different sample types were studied with regard to their activity for CO oxidation, during a heating ramp. One sample was an EBL-microfabricated Pt/CeOx model catalyst with Pt disks 700 nm in diameter, arranged in ordered arrays, with a total active Pt area of about 0.4 mm(2). The other sample was a Pt wire with a diameter of 0.1 mm and a length of about 1 mm. The light-off traces of these samples were measured during heating ramps for different relative CO partial pressures. Platinum bulk-like behavior for the CO-oxidation reaction was confirmed for both types of samples, indicating that the reactor is working properly and that the EEL fabrication technique is clean enough for model catalyst preparation. The total molar flow through the reactor at room temperature is typically 6 X 10(-8) mol/s, corresponding to a volume flow of about 1.7 mm(3)/s. (C) 2000 American Vacuum Society. [S0734-2101(00)03104-3].