Effect of CO on the morphology of Pt nanoparticles supported on TiO2 (110)-(1xn)

The effect of CO on the morphology of Pt nanoparticles of different sizes (1-4 nm) supported on TiO2 (1 1 0)-(1 x n) surface was investigated by scanning tunnelling microscopy (STM). The CO pressure was varied in the range of 10(-3)-10(1) 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. (C) 2004 Elsevier B.V. All rights reserved.