Mass-selected metal clusters, production

Fig. 1.35. Experimental setup for the investigation of gas-phase catalytic activity of mass-selected metal clusters. The cluster ions are sputtered from solid targets with a CORDIS, mass-selected (Qi), and guided at low energies (Qo and Q2) into the temperature controllable octopole ion trap. By means of appropriate switching of the lenses Li and L2, the reaction products are extracted and subsequently mass-analyzed by another quadrupole mass filter (Q3) [32,186]...

Platinum and palladium were among the first metals that were investigated in the molecular surface chemistry approach employing free mass-selected metal clusters [159]. The clusters were generated with a laser vaporization source and reacted in a pulsed fast flow reactor [18] or were prepared by a cold cathode discharge and reacted in the flowing afterglow reactor [404] under low-pressure multicollision reaction conditions. These early measurements include the detection of reaction products and the determination of reaction rates for CO adsorption and oxidation reactions. Later, anion photoelectron spectroscopic data of cluster carbonyls became available [405, 406] and vibrational spectroscopy of metal carbonyls in matrices was extensively performed [407]. Finally, only recently, the full catalytic cycles for the CO oxidation reaction with N2O and O2 on free clusters of Pt and Pd were discovered and analyzed [7,408]. 

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