Preparation of siloxy focal dendron-protected TiO 2 nanoparticles and their photocatalysis

Abstract

TiO 2 nanoparticles were synthesized at ∼0 °C by hydrolyzing [(CH 3) 2CHO] 4Ti in 1-propanol solutions of poly(amido amine) dendrons with a siloxy focal point and long alkyl chain spacers. Transmission electron microscopic photographs showed that TiO 2 nanoparticle was 1–5 nm in size and protected by dendrons, when prepared at a mixing ratio 1:10 of Ti ion and dendron. At higher contents of Ti ion, TiO 2 nanoparticles aggregated up to a maximum size of 90 nm, depending on the dendron generation (first to third). It was confirmed from X-ray photoelectron spectroscopy that Si O Ti covalent bond was formed in dendron-protected TiO 2 nanoparticles. The ability of dendron-protected TiO 2 nanoparticles as a photocatalyst for the photodegradation of 2,4-dichlorophenoxyacetic acid was higher than that of nonprotected nanoparticle and superior at higher generation. It was suggested that the dendrons protecting TiO 2 nanoparticle have enough void volume to conserve guest molecules and behave effectively as a reservoir of guest molecules.