Growth of TiO2 nanotube arrays with simultaneous Au nanoparticles impregnation: photocatalysts for hydrogen production

Abstract

Um novo método para a fabricação de nanotubos (NTs) de TiO 2 organizados e impregnados com nanopartículas (NPs) de ouro foi desenvolvido, e as propriedades estruturais, morfológicas e ópticas dos NTs obtidos foram investigadas. Os arranjos de NTs de TiO 2 foram crescidos pela oxidação anódica de Ti metálico utilizando soluções eletrolíticas contendo íons fluoreto e NPs de Au. As estruturas resultantes foram caracterizadas por espectrometria de retroespalhamento Rutherford (RBS), difratometria de raios X com incidência rasante (GIXRD), microscopias eletrônicas de transmissão (TEM) e de varredura (SEM) e espectroscopia UV-Vis. Tanto os arranjos de NTs sem Au quanto os impregnados com Au mostraram atividade fotocatalítica boa e estável na geração de hidrogênio a partir de misturas água/metanol. Os nanotubos de TiO 2 contendo Au foram mais ativos na fotogeração de hidrogênio do que os NTs de TiO 2 sem Au.A novel method for the fabrication of TiO 2 nanotubes (NTs) impregnated with gold nanoparticles (NPs) is reported. TiO 2 NT arrays were grown by anodic oxidation of Ti metal using fluoride electrolytes containing Au NPs. Resulting structures were characterized by Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffractometry (GIXRD), transmission and scanning electron microscopy (SEM and TEM) and UV-Vis spectroscopy. Au-free and Au-impregnated TiO 2 NT arrays showed good and stable photocatalytic activity for hydrogen generation from water/methanol solutions. Au-containing TiO 2 NTs presented higher hydrogen photogeneration activity than Au-free TiO 2 NTs.

On the formation of anisotropic gold nanoparticles by sputtering onto a nitrile functionalised ionic liquid

“…6 Among all employed PVD methods to prepare colloidal NPs, sputtering deposition onto ionic liquids (ILs) has several advantages since its versatility allows a good control over the size and size distribution of the NPs, 7,8 which is of great importance for special applications. [9][10][11][12][13][14] Moreover, in the case of sputtering deposition onto ILs, very stable spherical NPs are easily prepared by simply adjusting the physical parameters during the sputtering process, allowing for control of the NPs size and size distribution without the addition of extra stabilisers. 15 However, the factors that govern NPs growth in the sputtering process are still unclear.…”

Photosensitised Degradation of Organic Dyes by Visible Light Using Riboflavin Adsorbed on the Surface of TiO2Nanotubes

“…TiO 2 NTs were annealed at 400 °C for 3 h in air atmosphere to obtain the anatase phase. 47,49,51 Finally, TiO 2 NTs were impregnated with RF. The inset of Figure 1-top shows that after RF impregnation, the SEM image of the NTs is blurred and the visualisation of the NTs structure is not clear.…”

“…[47][48][49] After anodisation, the TiO 2 NTs were annealed at 400 °C for 3 h in air atmosphere in order to crystallise the oxide nanotubes layer. The nanotube structures were characterised by scanning electron microscopy (SEM) obtained with EVO50-Carl Zeiss equipment.…”

“…Gas phase product measurements were carried out in a calibrated, gas-closed photochemical reactor made of polytetrafluoroethylene (PTFE) under continuous magnetic stirring. 49,51 A quartz window allowed irradiation of the aqueous mixture under a wide incident spectral range, including UV and visible light. A 150 W mercury-xenon lamp (Sciencetech Inc.) operating at about 90% power was used as an excitation source.…”

Photocatalytic Activity and RNO Dye Degradation of Nitrogen-doped TiO2 Prepared by Ionothermal Synthesis

“…11 Given the current state-of-art, 5,[12][13][14] it is highly desirable to identify new synthesis routes for TiO 2 doping in order to obtain visible light-active photocatalysts. TiO 2 , doped or not, has been synthesized using techniques such as sputtering, 15,16 chemical vapor deposition, 17,18 sol-gel process, 19,20 hydrothermal process, 7 electrochemical methods, 21,22 and, more recently, ionothermal synthesis. 23,24 Ionothermal synthesis was referred for the first time in 2004 by Cooper et al 25 to distinguish the synthesis carried out using solvents composed predominantly by ionic liquids (IL) or deep eutectic mixtures (EU) from hydrothermal preparations, which take place in a predominantly molecular solvent.…”