Selective photo-deposition of Cu onto the surface of monodisperse oleic acid capped TiO2nanorods probed by FT-IR CO-adsorption studies

Abstract

A novel, non-aqueous, organometallic route to nanocomposite Cu@TiO₂ materials is presented. TiO₂ nanorods stabilized with oleic acid (OLA) were used as support for the photo-assisted deposition of Cu using the organometallic Cu(II) precursor [Cu(OCH(CH₃)CH₂N(CH₃)₂)₂] (1). The copper precursor 1 penetrates through the shell of OLA and is photo reduced to deposit Cu⁰ directly at the surface of the TiO₂ rods. The obtained Cu decorated nanorods were still soluble in nonpolar organic solvents without change of the morphology of nanorods. The Cu@TiO₂ colloid was characterized by means of UV-VIS, XRD, AAS, and HRTEM. FTIR CO adsorption studies provide evidence for Cu⁰ anchored at the titania surface by a characteristic absorption at 2084 cm⁻¹. Comparative studies of Cu-deposition were performed using CuCl₂ as simple Cu source which proved that the concept of organometallic disguise of the metal centre results in a higher reaction rate and the circumvention of non-selective reduction, parasitic side reactions and undesired agglomeration of the OLA stabilized titania nanorods.