A comparative scanning tunnelling microscopy study of the adsorption of [RhI(CO)2Cl]2 on the (1×1) and (1×2) surfaces of TiO2[1 1 0]

The room temperature interaction of [RhI(CO)2Cl]2 with the (1×1) and Ti2O3 added row (1×2) terminations of TiO2[1 1 0] has been studied using scanning tunnelling microscopy. Dissociative adsorption of [RhI(CO)2Cl]2 at the (1×1) surface leads to the formation of an adsorbed RhI(CO)2Cl species that coexists with particulate Rh0; the latter forms predominantly at step edges and terrace defects. The saturated RhI(CO)2Cl layer orders into domains showing a 12−11 relationship with respect to the underlying (1×1) structure. However, adsorption of the Rh organometallic at the Ti2O3 terminated (1×2) surface results solely in the formation of metallic Rh: there is no evidence for the formation of a stable RhI(CO)2Cl species. fference in surface reactivity between the two TiO2 surfaces is discussed in terms of their differing structure. A mode of adsorption of the RhI(CO)2Cl species on the (1×1) surface and the resulting structure of the geminal dicarbonyl adlayer are proposed.