The Shifts of Band Gap and Binding Energies of Titania/Hydroxyapatite Material

Linh, Nguyen Thi; Tuấn, Phan Đình; Dzung, Nguyen Van

doi:10.1155/2014/283034

Cited by 14 publications

(5 citation statements)

References 14 publications

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“…The peak in Figure c at 399.3 eV due to the N 1s peak corroborates positively with quinoid amine and benzenoid amine, which is consistent with the structure of PANI as reported by Golczak et al Figure d presents the core level O 1s spectra (530 eV) due to O bonds such as Ti–O–Ti and Ti–O–H . Ti 2p core level spectra are presented in Figure e at 459.2 eV and 464.9 eV due to Ti 2p 1/2 and Ti 2p 3/2 , respectively. , …”

Section: Resultsmentioning

confidence: 99%

Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water

2020

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Polyaniline (PANI)-wrapped TiO2 nanorods (PANI/TiO2), obtained through the oxidative polymerization of aniline at the surface of hydrothermally presynthesized TiO2 nanorods, were evaluated as photocatalysts for the degradation of Bisphenol A (BPA). Fourier-transform infrared spectroscopy analysis revealed the successful incorporation of PANI into TiO2 by the appearance of peaks at 1577 and 1502 cm–1 that are due to the CC and C–N stretch of the benzenoid or quinoid ring in PANI. Brunauer–Emmett–Teller analysis revealed that PANI/TiO2 had almost double the surface area of TiO2 (44.8999 m2/g vs 28.2179 m2/g). Transmission electron microscopy (TEM) analysis showed that TiO2 nanorods with different diameters were synthesized. The TEM analysis showed that a thin layer of PANI wrapped the TiO2 nanorods. X-ray photon spectroscopy survey scan of the PANI/TiO2 nanocomposite revealed the presence of C, O, Ti, and N. Photocatalytic activity evaluation under UV radiation through the effect of key parameters, including pH, contact time, dosage, and initial concentration of BPA, was carried out in batch studies. Within 80 min, 99.7% of 5 ppm BPA was attained using the 0.2 g/L PANI/TiO2 photocatalyst at pH 10. The quantum yield (QY) of these photocatalysts was evaluated to be 9.86 × 10–5 molecules/photon and 2.82 × 10–5 molecules/photon for PANI/TiO2 and TiO2, respectively. PANI/TiO2 showed better performance than as-synthesized TiO2 with a rate constant of 4.46 × 10–2 min–1 compared to 2.18 × 10–2 min–1. The rate of degradation of PANI/TiO2 was also superior to that of TiO2 (150 mmol/g/h vs 74.89 mmol/g/h). Nitrate ions increased the rate of degradation of BPA, while humic acid consistently inhibited the degradation of BPA. LC–MS analysis identified degradation products with m/z 213.1, 135.1, and 93.1. The PANI/TiO2 nanocomposite was reused up to five cycles with a removal of at least 80% in the fifth cycle. LC–MS results revealed three possible BPA degradation intermediates. LC–MS analysis identified degradation products which included protonated BPA, [C14H13O2 +], and [C9H11O+]. The PANI/TiO2 nanocomposite demonstrated superior photocatalytic activity with respect to improved QY and figure of merit and lower energy consumption.

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Section: Resultsmentioning

confidence: 99%

Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water

2020

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“…As shown in Sections and 4.2, synthesized powders can be characterized as Ti-modified hydroxyapatites, containing Ti-doped hydroxyapatite and titanium-bearing amorphous or crystalline impurity phases. As follows from DR spectroscopy data (Section ) and previous studies, ,,− modification of HAp by titanium leads to an emergence of absorption edge in the UV area with the respective red shift. The red shift is more pronounced at higher contents of titanium ions.…”

Section: Discussionmentioning

confidence: 74%

Ti-Modified Hydroxyapatites: Synthesis, Crystal Chemistry, and Photocatalytic Activity

Korneev,

Ryabchuk,

Kuz’mina

et al. 2024

Crystal Growth & Design

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The structural nature of photocatalytic properties of hydroxyapatites (HAp) synthesized from Ti-containing media (of Ti-modified hydroxyapatites) needs clarification. We synthesized hydroxyapatites from Ti-containing water solutions under various conditions and studied the received powder precipitations (before and after calcination at a temperature of 700 °C for 6 h) by a wide set of methods: powder X-ray diffraction (PXRD); vibrational, energy-dispersive X-ray, X-ray photoelectron, and diffuse reflectance spectroscopy; scanning electron microscopy, and gas phase photocatalytic activity tests. Analyzing the variations of unit cell parameters, we have proved that titanium is able to incorporate into the hydroxyapatite lattice in amounts of up to ∼10 wt % depending on synthesis conditions. At low concentrations (Ti/Ca ≤ 0.16), Ti 4+ ions incorporate predominantly to the P site of hydroxyapatite structure. At higher concentrations (0.16 ≤ Ti/Ca ≤ 0.28), additional Ti 4+ ions incorporate Ca sites. Besides, a significant share of titanium forms predominantly amorphous impurity phases, which transform into crystalline TiO 2 (anatase and rutile) upon calcination and are often undetectable by PXRD. The presence of crystalline titanium oxides (anatase and rutile) has a crucial effect on photocatalytic activity of calcined Ti-modified hydroxyapatites. Synthesized HAp/TiO 2 compositions are biocompatible heterostructured materials with photocatalytic activity comparable to that of commercial photocatalysts and could be recommended for medical−biological applications.

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“…Researching on the acetaldehyde gas decomposition of TiHAp by UV with VIS irradiation, the authors investigated the increase of activity comparing with when UV irradiation alone was used. Linh et al [46] also indicated the shift of bandgap of TiO 2 /HAp material synthesized by the hydrothermal process containing TiO(OH) 2 and HAp gels. The binding energy values of Ca 2p, P 2p, and O1s levels are related to hydroxyapatite phase, whereas those of Ti 2p levels corresponded with the characterization of titanium (IV) in TiO 2 .…”

Section: The Promoted Impact Of Hydroxyapatite In the Photocatalytic mentioning

confidence: 98%

Evaluation of the Role of Hydroxyapatite in TiO2/ Hydroxyapatite Photocatalytic Materials

Truc¹,

Hong²,

No³

2019

Photocatalysts - Applications and Attributes

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The TiO 2 /hydroxyapatite (HAp) composite has attracted much attention as a photocatalyst for pollution treatment in water or air because this composite can improve the properties of pure TiO 2 including a low efficiency, narrow light response range, low adsorption capacity for hydrophobic contaminants, and difficult recovery of TiO 2 particles after using in Aquarius environment. To obtain the best composite containing the two components including TiO 2 and HAp, the role of HAp in TiO 2 /hydroxyapatite photocatalytic material should be analyzed and evaluated. This chapter will significantly present a review of the role of HAp in the TiO 2 /hydroxyapatite composite including the adsorption ability of contaminations and the promoted impacts of HAp component.

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The Shifts of Band Gap and Binding Energies of Titania/Hydroxyapatite Material

Cited by 14 publications

References 14 publications

Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water

Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water

Ti-Modified Hydroxyapatites: Synthesis, Crystal Chemistry, and Photocatalytic Activity

Evaluation of the Role of Hydroxyapatite in TiO2/ Hydroxyapatite Photocatalytic Materials

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The Shifts of Band Gap and Binding Energies of Titania/Hydroxyapatite Material

Cited by 14 publications

References 14 publications

Polyaniline-Coated TiO2Nanorods for Photocatalytic Degradation of Bisphenol A in Water

Polyaniline-Coated TiO2Nanorods for Photocatalytic Degradation of Bisphenol A in Water

Ti-Modified Hydroxyapatites: Synthesis, Crystal Chemistry, and Photocatalytic Activity

Evaluation of the Role of Hydroxyapatite in TiO2/ Hydroxyapatite Photocatalytic Materials

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Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water

Polyaniline-Coated TiO₂Nanorods for Photocatalytic Degradation of Bisphenol A in Water