Infrared spectroscopic investigations of zeolites and adsorbed molecules. Part V. Carbon dioxide

Abstract

When bivalent cation-exchanged, but not univalent or decationized, Type X or Y zeolites are heated at 500° in the presence of carbon dioxide, two or three bands appear in the 1600 to 1300 cm−1 region of the infrared spectrum. These bands are stable even at 700°, and their frequencies are cation-dependent. They are assigned to a unidentate surface carbonate species, which (in the case of Ca Y) blocks about 20% of the surface cations.