Infrared spectra are reported of Ru/TiO2 and Ru-Rh/TiO2 exposed to CO + H-2 at 553 K and 1.5 MN m(-2) (15 atm). The Ru-Rh catalyst contained both exposed Ru and Rh atoms, which during reaction favoured adsorbed linear CO on Ru and bridged CO on Rh, Formation of an inactive long-chain hydrocarbon was accompanied by the appearance of a short-chain hydrocarbon which could be subsequently converted to methane, Ethoxide and ethanoate ions resulted from catalysis involving Rh. The results contrast with previous data for Ru-Rh/SiO2. A 14:1 ratio of CO:H-2 over Ru-Rh/TiO2 predominantly gave methane and an adsorbed CH2-containing hydrocarbon. The mixed metal catalyst generated more methane but less surface hydrocarbon than either Ru/TiO2 or Rh/ TiO2 catalysts.