Plasmonic Titania Photocatalysts Active under UV and Visible-Light Irradiation : Influence of Gold Amount, Size, and Shape

Abstract EN

Plasmonic titania photocatalysts were prepared by titania modification with gold by photodeposition.

It was found that for smaller amount of deposited gold (≤0.1 wt%), anatase presence and large surface area were beneficial for efficient hydrogen evolution during methanol dehydrogenation.

After testing twelve amounts of deposited gold on large rutile titania, the existence of three optima for 0.5, 2 and >6 wt% of gold was found during acetic acid degradation.

Under visible light irradiation, in the case of small gold NPs deposited on fine anatase titania, the dependence of photoactivity on gold amount was parabolic, and large gold amount (2 wt%), observable as an intensively coloured powder, caused photoactivity decrease.

While for large gold NPs deposited on large rutile titania, the dependence represented cascade increase, due to change of size and shape of deposited gold with its amount increase.

It has been thought that spherical/hemispherical shape of gold NPs, in comparison with rod-like ones, is beneficial for higher level of photoactivity under visible light irradiation.

For all tested systems and regardless of deposited amount of gold, each rutile Au/TiO2 photocatalyst of large gold and titania NPs exhibited much higher photoactivity than anatase Au/TiO2 of small gold and titania NPs.