Possible future developments of new automobile catalysts undoubtedly utilize transient phenomena at the change of gas composition under the cooperative functions of the catalytic components such as noble metal particles, supports and third additives including 'migration' of adsorbed species and their temporal 'storage'. To explore highly cooperative heterogeneous arrangements of the catalytic components, a new tool to detect transient products from artificially designed small area samples in the millisecond range was developed, which is more robust and tolerant for dynamic changes of vacuum conditions than the conventional UHV surface science tools. The tool employs four pulsed valves to supply a planar sample surface with sub-millisecond gas pulses of different species at different timings and a time of flight mass spectrometer which detects simultaneously all the species formed by the surface reaction. It also has a sample preparation chamber in which thin films such as Pt or CeO₂ can be deposited on the samples and the samples can be transmitted to the main reaction chamber without breaking the vacuum. To display the performance of the tool, some initial results of CO+O₂, NO+H₂ and C₃H₆+O₂ reactions on the conventional but planar Al₂O₃ catalysts impregnated with Pt or on thin Pt films are presented.

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