The present paper summarizes the results of comprehensive studies by a set of methods of the processes of reduction of copper chromite and of solid solutions of copper ions in zinc oxide. The composition and structure of copper-containing oxide catalysts in hydrogen medium and the nature of activated hydrogen species were investigated. Quantitative data on the interaction between hydrogen and the oxide catalysts and on the interaction of molecules to be hydrogenated with the reduced state of the catalysts are presented. The mechanisms for the synthesis of methanol from CO and CO2 and for the hydrogenation of acetone to isopropanol are discussed.