Structural and optical characteristic of single crystal rutile-titania nanowire arrays prepared in alumina membranes

Int J Applied Ceramic Tech

Akhavan-Safaei

Bafandeh

2018

In this study, SnO2 nano‐tube/wire arrays with a diameter in the range of 90‐120 nm and several micrometers in length were synthesized by the liquid phase deposition (LPD) method. The study of structural properties was performed by XRD, Raman and TEM, while the optical properties were measured using UV‐visible absorption and photoluminescence spectroscopy. The Raman spectra of the nano‐tubes/wires revealed the presence of 5 vibration peaks assigned to the tetragonal rutile SnO2 structure in agreement with the XRD results. The estimated optical direct band gap from UV‐visible absorption spectra was found to be 3.73‐3.88 eV. The observed blue shift of the optical band gap can be explained by the higher formation of mesoporous particles on the exposed surface to the photons. The photoluminescence (PL) spectra of the nano‐tubes/wires exhibited a rather broad and intense emission band centered at around 560‐569 nm.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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UV‐visible absorption and photoluminescence characteristics of SnO₂ nano‐tube/wire arrays fabricated by LPD method

Int J Applied Ceramic Tech

Akhavan-Safaei

Bafandeh

2018

“…It is also known that the surface states in TiO 2 nanostructures can be different depending on the preparation method . Some techniques and technologies for fabrication of 1D TiO 2 nanostructure arrays are used nowadays, for example, atomic layer deposition, anodization of Ti foil, hydrothermal, sol‐gel template, liquid phase deposition (LPD) . Among all these, LPD process is one of the simplest and most practical approaches to fabricate the metal oxide or hydroxide films .…”

Section: Introductionmentioning

confidence: 99%

Effect of annealing on UV‐visible absorption and photoluminescence behavior of liquid phase deposited TiO₂ nanorods

Int J Applied Ceramic Tech

Bafandeh

2019

In this work, anatase and rutile TiO 2 nanorods were fabricated using one-step liquid phase deposition process, followed by heat treatment in the range 300-800°C.The direct and indirect band gap of the TiO 2 nanorods was estimated form optical absorption data which illustrated a red shift at higher temperatures owing to the different nature of excitons in anatase and rutile phases. The photoluminescence (PL) spectra revealed the presence of two main emission bands consisting of four peaks.It was found that two high-energy peaks located at 2.95-3.30 eV could be generated from exciton transitions from the conduction band to the valence band of TiO 2 nanorods, while two low-energy peaks located at 2.43-2.64 eV may arise from surface state transitions. The PL intensity firstly increased with temperature and at 500°C reached a maximum value, then decreased through increasing temperature up to 800°C. These variations in the intensity of PL emission could be explained in terms of changes in phase structure, crystallinity, and amount of the oxygen vacancies, which are all dependent to the annealing temperature based on X-ray diffractometer and X-ray photoelectron spectrometer studies. These results indicated that annealing temperature allows to manipulate the properties of TiO 2 nanorods for opto-electronic applications. K E Y W O R D Sannealing temperature, photoluminescence, polycrystalline TiO 2 nanorods, UV-visible absorption, XPS analysis 2430 |

“…To overcome the drawback of low photocatalytic efficiency, considerable efforts have been taken, such as dimensionality reduction [4], metal and non-metal doping [5], and semiconductor coupling [6]. Onedimensional (1D) TiO 2 nanostructures, including nanobelts, nanofibers, nanorods, nanowires, and nanotubes [7][8][9][10][11] can be considered as one of good 108…”

mentioning

confidence: 99%

Photocatalytic degradation evaluation of N-Fe codoped aligned TiO2 nanorods based on the effect of annealing temperature

2020

J Adv Ceram

In this paper, a comparative study on the photocatalytic degradation of the Rhodamine B (RhB) dye as a model compound using N-Fe codoped TiO 2 nanorods under UV and visible-light (λ ≥ 420 nm) irradiations has been performed. TiO 2 photocatalysts were fabricated as aligned nanorod arrays by liquid-phase deposition process, annealed at different temperatures from 400 to 800 ℃. The effects of annealing temperature on the phase structure, crystallinity, BET surface area, and resulting photocatalytic activity of N-Fe codoped TiO 2 nanorods were also investigated. The degradation studies confirmed that the nanorods annealed at 600 ℃ composed of both anatase (79%) and rutile phases (21%) and offered the highest activity and stability among the series of nanorods, as it degraded 94.8% and 87.2% RhB in 120 min irradiation under UV and visible-light, respectively. Above 600 ℃, the photocatalytic performance of nanorods decreased owning to a phase change, decreased surface area and bandgap, and growth of TiO 2 crystallites induced by the annealing temperature. It is hoped that this work could provide precious information on the design of 1D catalyst materials with more superior photodegradation properties especially under visible-light for the further industrial applications. and 3.2 eV for rutile phase), which allows it to absorb only a small portion of sunlight corresponding to the UV region of solar spectrum. On the other hand, the recombination rate of photo-generated electron and hole pairs in TiO 2 is high [3]. Hence, these conclude the low photocatalytic efficiency of TiO 2 in the visible region. To overcome the drawback of low photocatalytic efficiency, considerable efforts have been taken, such as dimensionality reduction [4], metal and non-metal doping [5], and semiconductor coupling [6]. Onedimensional (1D) TiO 2 nanostructures, including nanobelts, nanofibers, nanorods, nanowires, and nanotubes [7][8][9][10][11] can be considered as one of good 108