Catalytic oxidation of carbon monoxide on monodispersed platinum clusters:Each atom counts

Nanoclusters open fascinating opportunities for quantum engineering because quantum-size effects become dominant in determining catalytic,(1-3) optica l,(4) electronic,(5) and magnetic(6) properties. We succeeded in the contro lled production of low-energy and high-flux monodispersed cluster beams, wh ich allow for a systematic study of their reactivity after deposition onto a chemically inert substrate. We investigated the catalytic reaction that i s the oxidation of CO on platinum and observed a distinct atom by atom size dependency for monodispersed platinum clusters on thin MgO(100) films. The se results clearly show that the efficiency of a heterogeneous catalytic re action can be tuned by the judicious choice of particle size.