Simultaneous induction of high level thermal and visible-light catalytic activities to titanium(IV) oxide by surface modification with cobalt(III) oxide clusters.

This study first presents a "TiO2-based eco-catalyst" working in the dark and under visible-light irradiation for the degradation of environmental organic pollutants. Molecular scale cobalt(III) oxide clusters are formed on the surface of highly active anatase TiO2 nanoparticles (Co2O3-TiO2) by the chemisorption-calcination cycle method. Co2O3-TiO2 exhibits very high visible-light activities for the degradation of 2-naphthol and formic acid used as model organic pollutants. Unprecedented thermocatalytic activity is concomitantly endowed on TiO2 by the surface modification. Prolonging reaction time in the Co2O3-TiO2 photo- and thermo-catalyzed reactions leads to the decomposition of 2-naphthol and formic acid to CO2. The essential action mechanisms of the Co2O3 clusters in the photocatalysis and thermocatalysis of Co2O3-TiO2 were discussed on the basis of spectroscopic and electrochemical data.