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 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.

Colloidal Strategies for Preparing Oxide‐Based Hybrid Nanocrystals

“…The altered carrier separation dynamics in such HNCs can be advantageously manipulated in order to benefit from either higher photocatalytic reaction yields or enhanced charge storage capability under equilibration of the Fermi levels of two materials, as well as modulate the metal surface plasmon absorption. [31][32][33][34][35][36] A few attempts to form core@shell associations of two semiconductors have been also reported. They involve the coupling of ZnO with CdSe or CdS.…”

“…[25,28] Another class of core@shell structures that have been obtained by this scheme is represented by oxide@metal HNCs, which normally combine ZnO or TiO 2 with Au, Ag, Pt or Cu. Typical preparations start from an alcohol suspension of weakly organic-passivated oxide NCs on which either chemical [31][32][33][34] or oxide-photocatalyzed reduction [35][36] of the desired metal precursors is accomplished. Depending on the specific experimental conditions used, the deposition process can achieve various degrees of surface coverage, leading to oxide NCs decorated with small island-like metal patches or entirely coated by a shell of irregular thickness.…”

Nano-brass colloids: synthesis by co-hydrogenolysis of [CpCu(PMe3)] with [ZnCp*2] and investigation of the oxidation behaviour of α/β-CuZn nanoparticles

“…11 Photocatalytic deposition of nano-Cu onto the surface of ZnO nanoparticles and as well onto free-standing oleic acid (OLA) capped monodisperse TiO 2 nanorods was studied, in order to obtain Cu@ZnO and Cu@TiO 2 composite nanoparticles dispersed as a colloidal solution. 12,13 These investigations focusing on the nanochemistry of the Cu/ZnO system have been largely motivated by the goal to achieve a quasi-homogeneous, non-aqueous colloidal model of the Cu/ZnO heterogeneous solid state catalyst for methanol synthesis. Binary Cu/ZnO and ternary Cu/ZnO/Al 2 O 3 powder materials prepared by classical co-precipitation-calcinationreduction protocols represent commercial, well-established heterogeneous catalysts of the large-scale industrial production of methanol from carbon monoxide and hydrogen and are also important for the steam reforming of methanol to produce hydrogen within the frame of the upcoming hydrogen technology (fuel cells).…”

Photochemical formation of semiconducting nanostructures

“…Microcrystalline and nanocrystalline oxide semiconductors can provide the basis for the photocatalytic formation of a wide range of metal-semiconductor nanostructures, such as TiO 2 /Pt 0 , TiO 2 /Pd 0 [119,144,145], TiO 2 /Rh 0 [146], TiO 2 /Au 0 [119,[147][148][149][150][151][152][153][154][155][156][157], TiO 2 /Ag 0 [131,150,155,, TiO 2 /Cu 0 [106,107,[181][182][183][184][185][186][187], TiO 2 /Hg 0 [181], TiO 2 /Ni 0 [188], TiO 2 /Cd 0 [189,190], TiO 2 /Zn 0 , TiO 2 /Mn 0 , TiO 2 /Tl 0 [190], ZnO/Au 0 [148], ZnO/Ag 0 [191,192], ZnO/Cu 0 [109,192,193], ZnO/Pd 0 [194], and ZnO/Pt 0 [126,192,195]. Features of the photoinduced production of metal-semiconductor nanostructures were investigated [196][197]…”