We performed H 2-D 2 exchange reactions over TiO x/Au(100) and compared the observed reaction kinetics with those reported for TiO x/Au(111) in order to clarify the influence of the Au and TiO 2 structures on dissociation of H 2 molecules. Low energy electron diffraction observations showed that the TiO 2 produced on Au(100) was disordered, in contrast to the comparatively ordered TiO 2 structure formed on Au(111). The activation energies and the turnover frequencies for HD formation over TiO 2/Au(100) agreed well with those for TiO 2/Au(111), clearly indicating that the hydrogen dissociation sites created over TiO 2/Au(100) were the perimeter interface between stoichiometric TiO 2 and Au, as was previously concluded for TiO 2/Au(111). We concluded that the creation of active sites for hydrogen dissociation was independent of the Au and TiO 2 structures consisting perimeter interface, and that local bonds that formed between Au and O atoms of stoichiometric TiO 2 were essential for the creation of active sites.
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