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

Abstract

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.