XPS NRA INVESTIGATIONS OF PARTICLE-SIZE EFFECTS DURING THE OXIDATION OF CU PARTICLES SUPPORTED ON OXIDIZED SI(100)/

In this study we investigate the effects of the particle size on the o xidation of supported Cu particles under equivalent experimental condi tions with respect to temperature and pressure. We compare the results of oxidation of 4 and 15 nm Cu particles supported on oxidised Si(100 ) at room temperature and 573 K. At room temperature and p = 10 Pa, th e oxidation of Cu-0 to Cu2+ at the surface of 4 nm particles proceeds significantly slower than in the case of 15 nm particles. At 573 K and p = 0.1 Pa, a reverse trend is observed: oxidation of 4 nm particles from Cu-0 to a Cu2+-oxide proceeds significantly faster than in the ca se of 15 nm particles, At both temperatures Cu-0 was oxidised to Cu2+- oxide through an intermediate Cu C-oxide.