Clusters of MnOx and CeOy were modified onto TiO2 (rutile) surface by chemisorption calcination cycle processing. Then the decomposition activity on 2-naphthol in water was evaluated at 50 degrees C under visible light illumination or in the dark. The modification of MnOx and CeOy clusters provided decomposition activity on 2-naphthol in the dark. It was increased by visible light illumination. The decomposition activity in the dark was dependent on the reaction temperature. The synergy effect in the co-modification of these two clusters was inferred from the reaction constants. Although the activity in the dark decreased gradually through repeated use and resultant reduction of MnOx and CeOy clusters, it recovered by UV illumination and subsequent heating at 80 degrees C in ambient air. (C) 2016 Published by Elsevier B.V.