The adsorption of triethylenediamine (TEDA) on Lewis acid (Al3+) sites of the highly dehydroxylated Al2O3 surface has been observed by FT-IR spectroscopy. This was done by monitoring the competitive adsorption of TEDA and CO on the Al3+ sites. A stoichiometric replacement of Al3+-Co species was observed as Al3+ -TEDA surface species were formed.