In this paper we describe the use of differently sized PbSe quantum dots as photosensitizers for anatase TiO2 nanowires under visible light illumination. After the organometallic synthesis of PbSe quantum dots with three different average diameters (1.8,2.5 and 4.7 nm), the nanocrystals were attached to the surface of nanowires with thioglycolic acid as a linker molecule. These quantum dot decorated nanowires were used as photocatalyst in the methyl orange degradation model reaction with promising results. The best performance achieved was 90% degradation of the initial concentration of methyl orange in six hours over 2.5 nm PbSe quantum dot sensitized nanowires using a 40W quartz UV lamp equipped with a 400 nm cut-off filter. (C) 2015 Elsevier B.V. All rights reserved.