Shape tailored Pd nanoparticles’ effect on the photocatalytic activity of commercial TiO2

Abstract

Shape-controlled synthesis of noble metal nanoparticles and their impact on the photocatalytic activity of semiconductor oxides is continuously gaining more and more attention. Hence, commercial titania-based TiO2-Pd nanocomposites were synthetized and characterized, using spherical and cubical Pd nanoparticles. The obtained photocatalysts were analyzed using optical (DRS) as well as morphological and structural (XRD, HR-TEM) methods in order to understand their properties. The effects of the Pd nanoparticles’ shape on different commercial titania-based catalysts were highlighted in terms of photocatalytic efficiencies toward model organic pollutants (phenol and oxalic acid), evolution of reaction intermediates (hydroquinone, pyrocatechol and resorcinol) and photocatalytic H2 production. It was found that both geometries (spherical, cubic) can enhance the activity of the base photocatalyst, although each Pd morphology modified the ratio of the primary degradation intermediates. Moreover, the photocatalytic hydrogen production of the spherical nanoparticles proved to be more efficient as the cubic ones. The observed activity differences were attributed to a possible change in the electron-transfer process, induced by the different Pd morphologies.