The photocatalytic activity of the composites TiO 2 −MO x (M = Ni, Cu, Zn, Fe, Cr) was studied in the reaction of hydrogen generation from aqueous alcoholic suspensions under UV light. The samples modified by the oxides of the metals capable of being reduced from oxides under photocatalytic conditions showed a high catalytic activity. The studied modifiers were divided in three groups in terms of their effect of the photocatalytic activity of TiO 2 : activating (NiO, CuO), inhibiting (Fe 2 O 3 ), and indifferent (ZnO, Cr 2 O 3 ).