Infrared spectra of adsorbed pyridine were taken on a Bruker VERTEX 70 FT-IR spectrometer. The samples were made into selfsupporting wafers and were evacuated in an IR cell at 350 C for 120 min. IR background spectra were recorded after the samples were cooled down to room temperature. Pyridine was thenadmitted into the IR cell and the IR spectra of adsorbed pyridine
were recorded after a degassing at 250 C for 30 min.