FACILE HYDROGENATION OF CARBON-DIOXIDE AT AL(111) SURFACES - THE ROLEOF COADSORBED WATER

The chemisorption of carbon dioxide and its reactivity in the presence of coadsorbed water has been investigated at Al(111) surfaces through a combination of in situ X-ray and electron energy-loss spectroscopie s. Carbon dioxide forms surface carbonate at low temperatures, which i s readily reduced to form surface carbide and oxide. However, the part icular significance of the present work is that when coadsorbed with w ater, there is a low-energy pathway to surface formate. The vibrationa l loss spectra are compared with spectra of model surface formates gen erated at Al(111) through interaction with formic acid and also when t he latter is coadsorbed with water.