Effect of CO on the morphology of Pt nanoparticles supported on TiO2(1 1 0)-(1 × n)

The effect of CO on the morphology of Pt nanoparticles of different sizes (1–4 nm) supported on TiO2(1 1 0)-(1 × n) surface was investigated by scanning tunnelling microscopy (STM). The CO pressure was varied in the range of 10−3–101 mbar. It was found that CO adsorption induces a significant increase in the initial size of the Pt nanoparticles of 1–2 nm even at room temperature. The agglomeration, however, is characteristically preceded by disruption of the smaller Pt nanoclusters at lower CO pressures. This finding was explained by CO-assisted Ostwald ripening, in which the mass transport proceeds via surface carbonyl intermediates.