Dynamic studies of CO oxidation on nanoporous Au using a TAP reactor

摘要

The oxidation of CO on nanoporous Au (NPG), in particular the activation of molecular O_2, was investigated by a combination of kinetic and temporal analysis of products (TAP) measurements. Continuous reaction measurements in a flow of reaction gas, at atmospheric pressure, show a catalytic behavior of the NPG, with the activity decreasing to 33% of the initial activity over 1000 min on stream. In contrast, during simultaneous pulsing of CO and O_2, the formation of CO_2 on the NPG catalyst rapidly decreased to values below the detection limit after reactive removal of the surface oxygen species present after sample preparation. Possible mechanisms explaining this discrepancy are discussed, using further information from multi-pulse TAP experiments, which revealed that molecular O_2 can be activated and stored on NPG catalyst at room temperature, though with a low probability.