Visible active gold/carbon co-doped titanium dioxide photocatalytic nanoparticles for the removal of dyes in water

Gold/carbon co-doped TiO2 photocatalysts with different contents of gold were prepared using a wet chemical technique, immobilized on fused silica and tested for their photocatalytic activity using methyl orange under visible light. Co-doping significantly red shifted the absorption edge of the photocatalysts. The synergistic effects between gold and carbon were best when the Au content was 1.0% where the lowest band gap of 2.45 eV and high photocatalytic activity towards methyl orange were achieved. Co-doping was also found to promote anatase to rutile phase transformation and the highest transformation was achieved by using 0.5% of Au. The effect of the simultaneous photodegradation of methyl orange and bisphenol A was also studied and it was observed that the photodegradation rates achieved for each contaminant was reduced in the bi-component system when compared to the mono-component system.