Molecular beam study of the CO oxidation on a regular array of Pd clusters on alumina

In this paper, we report first molecular beam study of CO oxidation on a regular array of Pd clusters on alumina. The constant distance with neighbour particles allows to overcome uncertainties in some parameter in the reaction, in comparison of other studies where particles have been grown or deposited on substrates that leads to random distribution. Furthermore, growing such array of particles by condensation of atoms on a surface ensures that the size distribution is very small and offers the possibility to study the size dependence of catalytic reaction and to correlate it to the adsorption energy of CO on Pd clusters. This work opens the way to a systematic study where unexpected size effects could occur, especially for very little sizes i.e. <; 100 atoms.