Surface acidity and basicity of a rutile powder

In this work, the interaction of a rutile powder sample with pyridine, 2,6-lutidine, CO, and CO2 was studied, at atmospheric pressure and under high-vacuum conditions, to investigate the acid/base character of the surface. The rutile powder has been characterized with DRIFT and XP spectroscopies, XRD, and thermal analysis. The adsorption experiments carried out at atmospheric pressure have been studied by means of DRIFT spectroscopy, whereas QMS and XPS have been used to follow the reactions under HV conditions. The comparison between the obtained results revealed the presence of Lewis acid sites on the TiO2 rutile surface. At least two nonequivalent Lewis acidic sites have been observed by means of CO chemisorption; basic sites were studied by adsorption Of CO2.