Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Processo FAPESP: 05/56120-8 ; Commercial TiO2 nanoparticles were superficially modified through polymeric resins obtained from polymerization of citrate complexes of Y3+ and Al3+ with ethylenglycol. The materials were treated at 450 A degrees C for 4 h to obtain modified nanoparticles, which were characterized by HR-TEM, Zeta potential and surface area through N-2 fisisorption. Rhodamine B photodegradation by visible light irradiation and in presence of those modified nanoparticles was compared with the same process in presence of unmodified commercial TiO2 nanoparticles. It was observed, by UV-visible spectroscopy, that the catalytic photoactivity in presence of modified nanoparticles was smaller than that observed with commercial TiO2 nanoparticles. However, the surface modifier played an important role in the photodegradation kinetic process, showing a non-linear relation between modifier amount and photodegradation rate, presenting a maximum value at 0.8% (w/w).