Diffusion versus desorption: Complex behavior of H atoms on an oxide surface

Abstract

Adsorption of atomic hydrogen on single-crystalline rutile TiO 2(110)-(1 x 1) (see picture) at room temperature leads to ordered H adlayers with (1 x 1) periodicity and many vacancies. Unexpectedly, almost no recombinative desorption of H2 (or H2O) occurs on heating to above 600 K, because the activation energy of 1.11 eV for H atoms migrating into the bulk is significantly smaller as shown by DFT calculations. (Figure Presented). © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.