TiO2 nanotubes arrays loaded with ligand-free Au nanoparticles: Enhancement in photocatalytic activity

A new protocol to synthesize size-controlled Au nanoparticles (NPs) loaded onto vertically aligned anatase TiO2 nanotubes arrays (TNTAs) prepared by electrochemical anodization is reported. Ligand-free Au NPs (<10 nm) were deposited onto anatase TNTAs supports, finely tuning the Au loading by controlling the immersion time of the support into metal vapor synthesis (MVS)-derived Au- acetone solutions. The Au/TNTAs composites were characterized by electron microscopies (SEM, (S)TEM), X-ray diffraction, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. Their photocatalytic efficiency was evaluated in toluene degradation in air under ambient conditions without thermal or chemical postsynthetic treatments. The role of Au loadings was pointed out, obtaining a three times enhancement of the pristine anatase TNTAs activity with the best sample containing 3.3 µg Au cm-2.