The present thesis comprises catalytic and mechanistic studies of the value-adding transformation of carbon dioxide into i) carbon monoxide and methane by hydrogenation of CO2 over potassium-modified Rh/Al2O3 catalysts as well as ii) 1-propanol, 1-butanol and iso-butanol by reaction of CO2 with hydrogen and olefins over Au/TiO2 and Au/SiO2 catalysts modified with alkali metals. For elucidating the specific role of the catalyst components related to catalyst activity and selectivity as well as reaction mechanism in situ and operando FTIR spectroscopic investigations have been carried out.