PHOTOCATALYTIC ACTIVITY OF Ag, Au-DEPOSITED TiO₂ NANOPARTICLES PREPARED BY SONOCHEMICAL REDUCTION METHOD

Abstract

The photocatalytic activity of metal-deposited TiO 2 was investigated with different surface coverage of nanosized noble metals ( Ag and Au ). The sonochemical deposition of nanosized metals on the TiO 2 matrix was prepared by adjusting the loading volumes of silver and gold precursors in an ultrasound-driven cell. Non-annealed Ag-TiO 2 exhibited the maximal activity in the optimal loading ranges of silver precursor (e.g. 0.2–0.3 ml of 1.0 wt.% AgNO 3 ), displaying the enhanced efficiency of electron–hole separation. The addition of nanosized Au on Ag-TiO 2 proved to be undesirable to improve the photocatalytic activity of Au/Ag-TiO 2 , except for the excessive loading of metal precursors (0.3 ml of 1.0 wt.% AgNO 3 + 0.2 ml of 1.0 wt.% HAuCl 4 ). XRD and XPS analysis confirmed the co-existence of Ag and Au species, and the reduction of PL (photoluminescence) intensity indicated the efficient separation of electron–hole pairs for optimal doping of nanosized metals on the TiO 2 matrix.