Detachable photocatalysts of anatase TiO 2  nanoparticles: Annulling surface charge for immediate photocatalyst separation

Al‐Hetlani, Entesar; Amin, Mohamed O.; Madkour, Metwally

doi:10.1016/j.apsusc.2017.03.151

Cited by 50 publications

(24 citation statements)

References 25 publications

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“…The TiO 2 BET surface areas were increased upon increasing the pH of preparation, this can be related to the increasing value of the pore volume. At P/P o = 0.8–1.0, the hysteresis loop obtained of type H4 which can be ascribed to the narrow slit like pores due to the large inter aggregated pores enriched by the generation of hollow interiors 11 . Consequently, TiO 2 NPs present a bimodal pore-size distribution ranging in the mesoporous region centered at 3.4 and >100 nm.…”

Section: Resultsmentioning

confidence: 93%

“…However, there are two major shortcomings that impede the industrial applicability of TiO 2 photocatalysis which are: 1) the large band gap which requires an ultraviolet illumination 9 and 2) the high electron–hole pair recombination rate 10 . Thus, many efforts have been devoted to surmount the issues associated with the TiO 2 NPs 11 .…”

Section: Introductionmentioning

confidence: 99%

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The effect of surface charge on photocatalytic degradation of methylene blue dye using chargeable titania nanoparticles

Azeez

Al‐Hetlani

Arafa

et al. 2018

Sci Rep

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425

138

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Herein, a simple approach based on tailoring the surface charge of nanoparticles, NPs, during the preparation to boost the electrostatic attraction between NPs and the organic pollutant was investigated. In this study, chargeable titania nanoparticles (TiΟ2 NPs) were synthesized via a hydrothermal route under different pH conditions (pH = 1.6, 7.0 and 10). The prepared TiΟ2 NPs were fully characterized via various techniques including; transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and dynamic light scattering (DLS). The influence of the preparation pH on the particle size, surface area and band gap was investigated and showed pH-dependent behavior. The results revealed that upon increasing the pH value, the particle size decreases and lead to larger surface area with less particles agglomeration. Additionally, the effect of pH on the surface charge was monitored by XPS to determine the amount of hydroxyl groups on the TiO2 NPs surface. Furthermore, the photocatalytic activity of the prepared TiΟ2 NPs towards methylene blue (MB) photodegradation was manifested. The variation in the preparation pH affected the point of zero charge (pHPZC) of TiO2 NPs, subsequently, different photocatalytic activities based on electrostatic interactions were observed. The optimum efficiency obtained was 97% at a degradation rate of 0.018 min−1 using TiO2 NPs prepared at pH 10.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

The effect of surface charge on photocatalytic degradation of methylene blue dye using chargeable titania nanoparticles

Azeez

Al‐Hetlani

Arafa

et al. 2018

Sci Rep

Self Cite

425

138

View full text Add to dashboard Cite

show abstract

“…The electrons act on the O 2 adsorbed on the semiconductor surface and form reactive superoxide radicals. These radicals react with organic dyes and produce CO 2 and H 2 O, so as to achieve photocatalysis [36]. The reaction processes can be understood with the following chemical equations [34][35][36][37]…”

Section: Resultsmentioning

confidence: 99%

Effects of Al doping on defect behaviors of ZnO thin film as a photocatalyst

Wang

et al. 2019

Materials Science-Poland

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Al doped ZnO (AZO) thin films were prepared on silica substrates by sol-gel method. The films showed a hexagonal wurtzite structure with a preferred orientation along c-axis. Suitable Al doping dramatically improved the crystal quality compared to the undoped ZnO films. Dependent on the Al dopant concentration, the diffraction peak of (0 0 2) plane in XRD spectra showed at first right-shifting and then left-shifting, which was attributed to the change in defect concentration induced by the Al dopant. Photocatalytic properties of the AZO film were characterized by degradation of methyl orange (MO) under simulated solar light. The transmittance of the films was enhanced by the Al doping, and the maximum transmittance of 80 % in the visible region was observed in the sample with Al concentration of 1.5 at.% (mole fraction). The film with 1.5 at.% Al doping achieved also maximum photocatalytic activity of 68.6 % under solar light. The changes in the film parameters can be attributed to the variation in defect concentration induced by different Al doping content.

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“…Titanium dioxide (TiO 2 ) has been proposed as an ideal semiconductor for the removal of recalcitrant compounds because it is chemically and biologically resistant and nontoxic, and can be simply applied (Ayati et al, 2014;Pelaez et al, 2012;Zhang, Wang, Liu, Sang, & Liu, 2017). The photocatalytic activity of TiO 2 mainly occurs on the surface of materials (Al-Hetlani, Amin, & Madkour, 2017;Yan et al, Research Article 2017). Thus, increases in interaction site area and improved surface morphology properties are believed to be the key factors for enhancing the photocatalytic degradation of recalcitrant compounds using TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Enhancing photocatalytic degradation of methyl orange by crystallinity transformation of titanium dioxide: A kinetic study

Adnan

Phattarapattamawong

2019

Water Environment Research

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This work aimed to enhance the photocatalytic degradation of methyl orange (MO) by crystallinity transformation of titanium dioxide (TiO2). In addition, the kinetic degradation of MO was determined. To transform its crystallinity, TiO2 was synthesized using a sol–gel method and calcined at between 200°C to 600°C. Calcination at a temperature of 250°C resulted in TiO2 that showed the best performance, corresponding to MO removal of 87% ± 7%. MO removal by TiO2 calcined between 250°C to 400°C was higher than for commercial TiO2 powder (Sigma‐aldrich) (62% ± 4%). TiO2 with a small crystallite size and high anatase fraction enhanced the photocatalytic degradation of MO, while the specific surface area and surface roughness seemed to play a minor role. The photocatalytic degradation of MO was NaCl‐independent, while the photocatalytic activity increased with decreased pH. Reused TiO2 showed similar photocatalytic degradation of MO compared with pristine TiO2, at 84 ± 2%. The oxidation kinetics of TiO2 calcined at 250°C were fitted to the Langmuir–Hinshelwood model (R2 = 0.9134). The kr and Ks values were 0.027 mg L−1 min−1 and 0.621 L/mg, respectively. Crystallinity transformation was a major factor in the enhancement of photocatalytic degradation of MO. Practitioner points Photocatalytic activity of TiO2 depends on calcination temperature, pH, and a number of UVC lamps. TiO2 with a small crystallite size and high anatase fraction enhanced the photocatalytic degradation of MO.

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Detachable photocatalysts of anatase TiO 2 nanoparticles: Annulling surface charge for immediate photocatalyst separation

Cited by 50 publications

References 25 publications

The effect of surface charge on photocatalytic degradation of methylene blue dye using chargeable titania nanoparticles

The effect of surface charge on photocatalytic degradation of methylene blue dye using chargeable titania nanoparticles

Effects of Al doping on defect behaviors of ZnO thin film as a photocatalyst

Enhancing photocatalytic degradation of methyl orange by crystallinity transformation of titanium dioxide: A kinetic study

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