The geometry of free-standing titania nanotubes as a critical factor controlling their optical and photoelectrochemical performance

Wawrzyniak, Jakub; Grochowska, Katarzyna; Karczewski, Jakub; Kupracz, Piotr; Ryl, Jacek; Dołęga, Anna; Siuzdak, Katarzyna

doi:10.1016/j.surfcoat.2020.125628

Cited by 25 publications

(23 citation statements)

References 79 publications

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“…The E bg of pristine titania NTs equals 3.09 eV, less than reported for bulk anatase (3.20 eV), [ 36 ] due to optimization of the spacing and geometrical features of the nanotubes. [ 37 ] As expected, the E bg values drop to 3.00 eV for Ni‐decorated sample, and further to 2.88 eV after irradiating with 10 mJ cm −2 . A similar trend was observed previously for laser‐treated Cu‐TiO 2 NTs, [ 38 ] which indicates synergistic effects of metal/metal oxide and laser processing in E bg reduction.…”

Section: Figuresupporting

confidence: 73%

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Wawrzyniak

Karczewski

Coy

et al. 2020

Adv Materials Inter

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The selective, laser‐induced modification of the nickel‐decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption band appears at 500 nm, where the local minimum can be found for bare nanotubes. The high‐resolution X‐ray photoelectron spectra indicate the presence of both metallic and hydroxide forms of nickel species. The electrode material treated with 355 nm pulses at 50 mJ cm−2 shows significantly improved current densities in the anodic regime, reaching nearly 300 mA cm−2 while exposed to solar radiation, whereas the untreated sample barely comes to 1.5 mA cm−2 in the same conditions. The tailored titania photoanode also exhibits two orders of magnitude higher donor concentration in comparison to the primary substrate as verified by Mott–Schottky analysis. The electrochemical analysis confirms the key role of laser annealing in enhancing the effectiveness of light‐driven water splitting.

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Section: Figuresupporting

confidence: 73%

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Wawrzyniak

Karczewski

Coy

et al. 2020

Adv Materials Inter

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“…The as-anodized nanotubes are about 800 nm long, have an inner diameter of 120 nm, a wall thickness of 11 nm, and are separated by 90 nm, which is consistent with our previous study [ 37 ]. Their overall morphology is not altered by ultrasonic bath modification either, aside from a few bald patches of detached NTs ( Figure S1 ).…”

Section: Resultssupporting

confidence: 92%

“…Moreover, we provide an example of modification with created colloid, using it to enhance the efficiency of oxygen production in the TiO 2 -based electrode by over an order of magnitude. Due to the easily adjustable TiO 2 nanotubes (NTs) morphology, facile production, high surface area, and stability [ 33 , 34 , 35 , 36 , 37 , 38 , 39 ], together with nickel nanoparticles, they have become a very strong, yet eco-friendly, duet for further research. The electrochemical properties of hybrids composed of Ni nanoparticles electrodeposited onto titania nanotubes were shown for example by Chen et al using nickel sulphate as NPs precursor [ 40 ].…”

Section: Introductionmentioning

confidence: 99%

Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles

et al. 2020

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Nowadays, more than ever, environmental awareness is being taken into account when it comes to the design of novel materials. Herein, the pathway to the creation of a colloid of spherical, almost purely metallic nickel nanoparticles (NPs) through pulsed laser ablation in ethanol is presented. A complex description of the colloid is provided through UV-vis spectroscopy and dynamic light scattering analysis, ensuring insight into laser-induced nanoparticle homogenization and size-control of the NPs. The transmission electron spectroscopy revealed spherical nanoparticles with a narrow size distribution, whereas the energy-dispersive X-ray spectroscopy accompanied by the X-ray photoelectron spectroscopy revealed their metallic nature. Furthermore, an example of the application of the colloidal nanoparticles is presented, where a quick, five-min ultrasound modification results in over an order of magnitude higher current densities in the titania-based electrode for the oxygen evolution reaction.

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“…When the as-anodized TiO 2 samples were annealed at 450 °C for 1 h in air, distinct XRD peaks at 25.3, 47.9, and 54.9° (anatase, JCPDS # 21-1272) as well as two elusive peaks at 27.4 and 54.1° (rutile, JCPDS # 21-1276) appear, confirming crystallization of the TiO 2 layer by the formation of the anatase phase along with the small amount of rutile (Figure a, red spectrum, and Figure S5). Based on the reported literature, the appearance of the rutile peaks can be ascribed to thermal oxidation of the Ti metal substrate at the Ti metal/oxide interface. − …”

Section: Resultsmentioning

confidence: 99%

Morphology and Optical Properties of Highly Ordered TiO₂ Nanotubes Grown in NH₄F/o-H₃PO₄ Electrolytes in View of Light-Harvesting and Catalytic Applications

Tesler

Altomare

Schmuki

2020

ACS Appl. Nano Mater.

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Highly ordered titanium dioxide nanotube (TiO2 NT) arrays were grown by electrochemical anodization of titanium in a molten NH4F/o-H3PO4 electrolyte. NTs with various diameters, lengths, wall thicknesses, and intertube distances could be obtained by tuning key anodization parameters such as the applied potential, anodization time, electrolyte temperature, concentration of NH4F, and H2O content. The morphology and optical properties were characterized by scanning electron microscopy and UV–vis spectroscopy techniques. We show that all aforementioned parameters have a strong influence on the nanostructured morphology and optical characteristics (reflectivity) of the formed nanotubular layers. Their optical features were simulated numerically to support the experimental measurements. We show that the optical features of anodic TiO2 nanotube layers result from the overlay of the individual optical properties of various “structural elements”, e.g., the NT barrier layer, top opening morphology, intertube spacing, and thermally formed oxide sublayer. Our results provide tools for “a priori” design with nanoscale precision of TiO2 structures with advanced optical features for light-harvesting and catalytic applications, e.g., in sensing, photocatalytic self-cleaning processes, solar hydrogen generation, or photovoltaics.

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The geometry of free-standing titania nanotubes as a critical factor controlling their optical and photoelectrochemical performance

Cited by 25 publications

References 79 publications

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles

Morphology and Optical Properties of Highly Ordered TiO₂ Nanotubes Grown in NH₄F/o-H₃PO₄ Electrolytes in View of Light-Harvesting and Catalytic Applications

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The geometry of free-standing titania nanotubes as a critical factor controlling their optical and photoelectrochemical performance

Cited by 25 publications

References 79 publications

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles

Morphology and Optical Properties of Highly Ordered TiO2 Nanotubes Grown in NH4F/o-H3PO4 Electrolytes in View of Light-Harvesting and Catalytic Applications

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Morphology and Optical Properties of Highly Ordered TiO₂ Nanotubes Grown in NH₄F/o-H₃PO₄ Electrolytes in View of Light-Harvesting and Catalytic Applications