Synthesis and Characterization of Au@TiO₂ NWs and their Catalytic Activity by Water Splitting: A Comparative Study with Degussa P25

Abstract

Different amount of gold nanoparticles (1, 3, 5, 10 wt%) were deposited on the surface of synthesized titanium oxide nanowires (TiO₂ NWs) and Degussa P25 (TiO₂-P25). The results evidenced the presence of small and dispersed gold particles on the surface of TiO₂ NWs and TiO₂-P25 and an increase in the specific surface area of all the composites. The photocatalytic activity was characterized by measuring the hydrogen production by water splitting, using UV-vis radiation. Au@TiO₂ NWs catalysts showed the highest production of hydrogen (1,436 μmol hg^-1), with a gold loading of 10 wt%, while in the case of Au@TiO₂-P25 the hydrogen production was slightly lower (800 μmol hg^-1), with a gold loading of 5 wt%. The enhancement in the hydrogen production was 11.5 times higher than that reported by the TiO₂ NWs catalyst (125 µmol hg^-1) and 5.2 times higher than the TiO₂-P25 (154 µmol hg^-1). The activity of the catalysts was found to be dependent both on the surface area of the composites and on the amount of gold.