PHOTOCHEMICAL FABRICATION OF TRANSITION METAL NANOPARTICLES USING CdS TEMPLATE AND THEIR CO-CATALYSIS EFFECTS FOR TiO2 PHOTOCATALYSIS

Abstract

Transition metal nanoparticles were prepared by chemical dissolution of CdS template from metal photodeposited CdS nanorod (length = 70–85 nm and width = 5–6 nm) heterocomposites. Size (9–10 nm) of metal nanoparticles obtained after CdS removal was larger than the size (4–6 nm) of metal nanodeposits over CdS template. The obtained Au nanoparticles displayed a broad red shifted absorption band at 660 nm, whereas Pt , Pd and Rh nanoparticles exhibit featureless absorption spectra. Elemental analysis confirms the complete removal of CdS template from Au – CdS ( Au — 2.65 at.%) and Ag – CdS ( Ag — 2.06 at.%) composites showing no Cd peak. These metal nanoparticles imparted dissimilar co-catalytic activity of TiO 2 for photocatalytic degradation of salicylic acid in the order Au > Pt > Pd > Ag > Rh as a function of their nature, electronegativity, redox potential and work function.