Plasmonic photocatalysts consisting of a mixture of Au nanospheres and Au nanorods on TiO2 support for improved visible light induced photocatalytic degradation properties

In this study the influence of shape polydispersity of the AuNPs on the photocatalytic activity of Au/TiO2 photocatalysts has been investigated. Gold nanorods (AuNRs) and gold nanospheres (AuNSs) were mixed at different volume ratios to make polydispersed samples. The prepared polydispersed gold nanoparticle samples were loaded onto TiO2 via the nucleation and growth method to obtain Au/TiO2 plasmonic photocatalysts. The results of Transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) confirmed the presence of the desired shapes and the formation of Au/TiO2 nanocomposites. The photocatalytic activity of Au/TiO2 photocatalysts was evaluated through the degradation of reactive orange 16 under visible light irradiation. The rate of degradation in the AuNRs was approximately 3 times faster compared to the AuNSs. The photocatalysts loaded with the mixed AuNRs-AuNSs nanoparticles showed the highest photocatalytic activity compared to the monodispersed samples. The photocatalytic degradation reached 90.15 % for 2:1 vol ratio of AuNRs to AuNSs in 60 min. of irradiation. The results indicate that a good photocatalytic efficiency after recycling the photocatalysts four times.