Anodic titania nanotubes decorated with gold nanoparticles produced by laser-induced dewetting of thin metallic films

Abstract

Herein, we combine titania layers with gold species in a laser-supported process and report a substantial change of properties of the resulting heterostructures depending on the major processing parameters. Electrodes were fabricated via an anodisation process complemented with calcination to ensure a crystalline phase, and followed by magnetron sputtering of metallic films. The obtained TiO2 nanotubes with deposited thin (5, 10 nm) Au films were treated with a UV laser (355 nm) to form Au nanoparticles on top of the nanotubes. It was proven that selected laser working parameters ensure not only the formation of Au nanoparticles, but also simultaneously provide preservation of the initial tubular architecture, while above-threshold laser fluences result in partial destruction (melting) of the top layer of the nanotubes. For almost all of the samples, the crystalline phase of the nanotubes observed in Raman spectra was maintained independently of the laser processing parameters. Enhanced photoresponse up to ca 6 mA/cm2 was demonstrated by photoelectrochemical measurements on samples obtained by laser annealing of the 10 nm Au coating on a titania support. Moreover, a Mott–Schottky analysis indicated the dramatically increased (two orders of magnitude) concentration of donor density in the case of a laser-treated Au–TiO2 heterojunction compared to reference electrodes.

Scanning with Laser Beam over the TiO2 Nanotubes Covered with Thin Chromium Layers towards the Activation of the Material under the Visible Light

“…Moreover, the position of the main anatase peak at 144 cm −1 remained unchanged regardless of the applied energy fluence used to modify electrode material ( Figure S2 ). It should be mentioned that the change in position was previously observed for pristine laser-treated titania nanotubes [ 30 , 40 ]. Nonetheless, similar behavior, namely no peak shift due to the laser treatment, was also reported for thin gold layers deposited onto TNT [ 40 ].…”

The Impact of Side-Selective Laser Tailoring of Titania Nanotubes on Changes in Photoelectrocatalytic Activity

“… Illustration of protocol to obtain laser-modified TiO 2 NTs, based on Au-decorated TiO 2 NTs. Reprinted with permission from [ 45 ]. Copyright (2022) Creative Commons Attribution.…”

“… XRD patterns for calcined TiO 2 nanotubes treated with different laser fluences. Reprinted with permission from [ 45 ]. Copyright (2022) Creative Commons Attribution.…”

Influence of Annealing Atmospheres on Photoelectrochemical Activity of TiO2 Nanotubes Modified with AuCu Nanoparticles

“…−1.0 V versus Ag/AgCl/0.1 M KCl. According to Grochowska et al, 67 the flat band potential for pure TiO 2 NTs calcined in a tube furnace at 450 °C in the air atmosphere was equal to −0.67 V versus Ag/AgCl/0.1 M KCl. Therefore, annealing in the argon atmosphere shifts the potential toward more negative values, and causes an increase in the concentration of defects.…”