Pd1/MgO(100): a model system in nanocatalysis

Nanocatalysts consist of small size-selected clusters adsorbed on uniform sites of a support material. Here, we focus on a simple model system, which is fabricated by soft-landing atomic Pd ions on oxygen vacancies (F-centers) of a MgO(1 0 0) surface (Pd1/MgO(Fs)). We used thermal desorption and infrared spectroscopies (TDS, FTIR) to study the acetylene polymerization and the CO oxidation catalyzed by this system. In one-heating-cycle experiments, only the formation of benzene is observed during the polymerization reaction and the combustion of CO leads to the formation of CO2 detected at 260 and 500 K. Experimental results in combination with ab initio calculations reveal the mechanisms of these reactions and demonstrate the role of surface defects in nanocatalysis. 2002 Elsevier Science B.V. All rights reserved.