Interface excess on Sb-doped TiO2 photocatalysts and its influence on photocatalytic activity

Titanium dioxide (TiO2) is a well-known photocatalyst that has been used in photocatalysis and has been studied as an alternative for artificial photosynthesis cells. Many works have tried doping this material with different elements to increase its photoactivity; however, a consequence of doping that has not received much attention is the segregation at the nanoparticle interfaces, such as the surface and the grain boundary (GB). In this study, Sb-doped TiO2 nanoparticles have been produced by the polymeric precursor method, with the compositional range varying from 0 to 2 mol% Sb. The surface excess was measured by the surface lixiviation method, and the GB excess was calculated considering the total amount of Sb and its solubility in the TiO2 bulk. The results showed that Sb interfacial segregation at both surface and GB increased the specific surface areas, reduced the crystallite sizes, increased the presence of the rutile phase, and changed the CO2 adsorption, evidenced by DRIFT spectroscopy. The photoactivity was tested by the degradation of acetaminophen (ACT) under UV irradiation, revealing an increase of similar to 53% of activity for 0.05 mol% Sb-doped TiO2 compared to undoped TiO2.