(406d) Probing Hydroxyl Groups on Metal-Supported 2-D Silica Films

Norton, A. M., University of Delaware
Boscoboinik, J. A., Brookhaven National Laboratory
Vlachos, D. G., University of Delaware
Zheng, W., University of Delaware
Tsapatsis, M., Johns Hopkins University
In catalysis, it is generally recognized that the performance of silica, as either the support or the active surface, is primarily determined by the surface hydroxyl species. Numerous studies have examined how water interacts with silica and zeolites, but due to the structural complexity and diversity of these materials, chemical properties of hydroxylated silica surfaces remain unknown. These issues are overcome, though, when we perform surface science studies on well-ordered, thin silica films supported on metal substrates. In the present work, we investigate water adsorption on two-dimensional (2-D) silicates and zeosil nanosheets under vacuum conditions using infrared reflection-absorption spectroscopy (IRRAS). We introduce defects (silanol groups) on the silicates and characterize their formation via H-D exchange with deuterated water. Finally, we compare our results with those reported for bulky silica materials.