The clusters [Ru6C(CO)16Me](-) supported on SiO2, Al2O3, and TiO2 were characterized by means of EXAFS, TPD, and FT-IR in relation to developments of new catalytic system. The EXAFS analysis demonstrated that the [Ru6C] framework which has an interstitial carbon atom was stable at 473 (silica), 523 (alumina), and 473 K (titania) under CO or CO + H2. The supported clusters produced methane upon heating in vacuum by the reaction with surface hydrogen-bonded OH groups, whereas in the presence of CO + H2, acetaldehyde was preferably produced, unlike [Ru6C(CO)16Me](-) in a homogeneous system where only methane was formed. The selectivity to acetaldehyde was larger with silica (77%) than with alumina (15%) or titania (10%).