Photocatalytic reduction and scavenging of Hg(II) over templated-dewetted Au on TiO${}_2$ nanotubes

Abstract

Gold-decorated TiO${}_2$ nanotubes were used for the photocatalytic abatement of Hg(II) in aqueous solutions. The presence of dewetted Au nanoparticles induces a strong enhancement of photocatalytic reduction and scavenging performances, with respect to naked TiO${}_2$. In the presence of chlorides, a massive formation of Hg2Cl2 nanowires, produced from Au nanoparticles, was observed using highly Au loaded photocatalysts to treat a 10 ppm Hg(II) solution. EDS and XPS confirmed the nature of the photo-produced nanowires. In the absence of chlorides and/or at lower Hg(II) starting concentrations, the scavenging of mercury proceeds through the formation of Hg-Au amalgams. Solar light driven Hg(II) abatements up to 90% were observed after 24h. ICP-MS analysis revealed that the removed Hg(II) is accumulated on the photocatalyst surface. Regeneration of Hg-loaded exhaust photocatalysts was easily performed by anodic stripping of Hg(0) and Hg(I) to Hg(II). After four catalytic-regeneration cycles only a 10% decrease of activity was observed.

References in corpus (3)

• Aligned metal oxide nanotube arrays: key-aspects of anodic TiO2 nanotube formation and properties
• Templated Dewetting-Alloying of NiCu Bilayers on TiO${}_2$ Nanotubes Enables Efficient Noble Metal-Free Photocatalytic $H_2$ Evolution
• Photocatalytic H2 generation using dewetted Pt-decorated TiO2 nanotubes - Optimized dewetting and oxide crystallization by a multiple annealing process

Cited by in corpus (1)

• Dewetted Au nanoparticles on TiO${}_2$ surfaces -- Evidence of a size-independent plasmonic photo-electrochemical response