PNNL

Abstract

The (111) surface of rutile TiO2 was prepared with argon-ion sputtering and vacuum annealing at 970 K. Scanning tunneling microscope observation revealed nanometer-scale domains of (1 x 1) and (1 x 2) phases covering the surface. Formic acid was dissociatively adsorbed on the surface at room temperature. The recombination and decomposition temperatures of adsorbed formate were similar to those reported on rutile surfaces of different orientations. The CH-related and COO-related stretching modes probed by high-resolution electron energy loss showed two types of formate. The wavenumbers of the vibrational modes can be interpreted with a mixture of monodentate, bidentate, or bridge form of adsorption. The number density and limited mobility of formate evaluated in microscope topography supports monodentate and bidentate forms.