The adsorption and thermal desorption of diethyl ether (DE) and perfluorodiethyl ether (PDE) on a porous silica surface were investigated by FT-IR under ultra high vacuum conditions. The IR spectra of adsorbed species in the 4000–1000 cm −1 range were reported, and for the first time, the vibrational spectra of adsorbates below 1300 cm −1 on porous silica surface were clearly resolved. Basically, both DE and PDE physisorbed onto the silica surface, but DE was found to form much stronger hydrogen bonds with surface hydroxyl groups than PDE and to desorb completely at higher temperatures. The changes in the adsorption geometry of DE during hydrogen bond formation and desorption processes are discussed. The chemistry of DE and PDE on SiO 2 , Al 2 O 3 and TiO 2 are also discussed.