Photocatalytic degradation of imazapyr using mesoporous Al2O3–TiO2 nanocomposites

Ismail, Adel A.; Abdelfattah, Ibrahim; Atitar, M. Faycal; Robben, Lars; Bouzid, Houcine; Al-Sayari, S.A.; Bahnemann, Detlef W.

doi:10.1016/j.seppur.2015.03.012

Cited by 58 publications

(22 citation statements)

References 47 publications

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“…However, its photocatalytic activity remains insufficient for practical applications because of the high recombination rate of photogenerated electronhole pairs (e --h + ) [2][3]. Thus, TiO2 is coupled with other metal oxides, such as ZrO2, CeO2, NiO, WO3 and Al2O3 in order to improve the photocatalytic activity [4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Guerrero-Araque

Ramírez-Ortega

Acevedo–Peña

et al. 2017

Journal of Photochemistry and Photobiology A: Chemistry

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2 Graphical abstract Highlights: ZrO2-TiO2 heterojunction with high photocatalytic activity were obtained by solgel. Energy states at heterojunction interface altered the semiconducting properties. 5 mol% ZrO2 in ZrO2-TiO2 heterojunction propitiated a better electron-hole separation. Photocatalytic activity is improved by favoring the charge transfer process. Direct and indirect charge transfer process involved in phototocatalytic process. Abstract.In this paper, ZrO2-TiO2 composites were synthesized by sol-gel method with different ZrO2:TiO2 molar ratios (01:99, 05:95 and 10:90). The results identified two trends; at a low ZrO2 content, the incorporation of Zr 4+ into the TiO2 lattice was possible provoking generation of oxygen vacancies (1 mol % of ZrO2); while at higher ZrO2 contents, ZrO2-TiO2 heterojunctions were created (5 and 10 mol % of ZrO2). The photocatalytic activity was evaluated by measuring photodegradation of phenoxyacetic acid, 2,4-dichlorophenoxyacetic acid or 4-chlorophenol solutions. The ZT-5 composite shows the best performance attributed to surface states at the interface of ZrO2-TiO2 heterojunctions.These surface states act as traps for charge carriers favoring the spatial separation of electron-hole pairs until reaching a maximum in the composite with 5 mol% of ZrO2. The ZT-5 composite showed the most negative flat band potential and the highest donor density indicating that these surface states are in optimal concentration. At higher ZrO2 contents, charge carrier separation is less effective, which decreases the photocatalytic activity.Nevertheless, the molecule structure has an impact on the direct or indirect charge transfer process as was evidenced by EIS measurements.

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Section: Introductionmentioning

confidence: 99%

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Guerrero-Araque

Ramírez-Ortega

Acevedo–Peña

et al. 2017

Journal of Photochemistry and Photobiology A: Chemistry

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“…Since visible light is accounted as the largest proportion of solar spectrum, the development of effective visible light-driven photocatalysts has become one of the significant subjects to improve the solar energy conversion and purify the environment [9][10][11][12][13][14]. TiO 2 is considered to be a first choice photocatalyst for environmental applications as results of its relatively high photocatalytic activity, biological and chemical stability, low-cost and long stable life [9][10][11][12][13][14]. However, it absorbs almost only the ultraviolet light (l < 400 nm), which means only 4-5% of visible solar spectrum can be utilized by TiO 2 owing to its high bandgap energy [15].…”

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confidence: 99%

Comparative study on photocatalytic performances of crystalline α- and β-Bi2O3 nanoparticles under visible light

Jalalah

Faisal

Bouzid

et al. 2015

Journal of Industrial and Engineering Chemistry

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120

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“…In the present results the presence of alumina plays an important role, acting as a charge transfer catalyst, where the electrons of TiO 2 can be transferred to the alumina, which delays the time of recombination of electron–hole pairs, the electrons generated are adsorbed on the structural defects of the alumina. The photoinduced holes oxidize − OH ions or H 2 O which are adsorbed on the surface to produce highly oxidizing •OH species . The production of •OH radical depends on the competition between oxidation of surface water by the holes and electron–hole recombination .…”

Section: Resultsmentioning

confidence: 99%

“…The photoinduced holes oxidize − OH ions or H 2 O which are adsorbed on the surface to produce highly oxidizing •OH species. 45 The production of •OH radical depends on the competition between oxidation of surface water by the holes and electron-hole recombination. 46 This •OH radical are considered the main species responsible for the photocatalytic oxidation of chemical compounds.…”

Section: Photocatalytic Activitymentioning

confidence: 99%

Alumina coating with TiO₂and its effect on catalytic photodegradation of phenol andp-cresol

Gómez

Angel

Ramos-Ramírez

et al. 2016

J. Chem. Technol. Biotechnol.

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BACKGROUND This study is focused on the peptization of Boehmite and titanium alkoxide (modified sol–gel method) to obtain Al2O3–TiO2 mixed oxides taking advantage of the physicochemical properties of TiO2 and Al2O3. TiO2 is an important semiconductor and the most active photocatalyst. Al2O3 is an insulator with high surface area and thermal, chemical and mechanical resistance. It is possible to produce high surface area materials, where TiO2 is dispersed on the alumina surface for photodegradation of pollutants. RESULTS γ‐Al2O3–TiO2 (5, 10 and 15 wt% TiO2) mixed oxides presented stabilization of the anatase phase. Rietveld studies showed incorporation of the Al3+ into the TiO2 anatase and Ti4+ into the Al2O3. They exhibit higher specific surface area than pure TiO2. The TiO2‐coated alumina surface with small TiO2 particles produced a large number of active sites on the surface. The sample with 15 wt% of TiO2 presented the highest photodegradation of p‐cresol and phenol. CONCLUSION The addition of TiO2 to the alumina improved the photoactivity of pure TiO2 producing materials with higher surface area covered with TiO2. Alumina delayed the recombination of photogenerated electron–hole pairs favoring the formation of highly reactive •OH radicals. The photodegradation of p‐cresol and phenols increased with TiO2 loading increase. © 2016 Society of Chemical Industry

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Photocatalytic degradation of imazapyr using mesoporous Al2O3–TiO2 nanocomposites

Cited by 58 publications

References 47 publications

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Comparative study on photocatalytic performances of crystalline α- and β-Bi2O3 nanoparticles under visible light

Alumina coating with TiO₂and its effect on catalytic photodegradation of phenol andp-cresol

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Photocatalytic degradation of imazapyr using mesoporous Al2O3–TiO2 nanocomposites

Cited by 58 publications

References 47 publications

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Interfacial charge-transfer process across ZrO2-TiO2 heterojunction and its impact on photocatalytic activity

Comparative study on photocatalytic performances of crystalline α- and β-Bi2O3 nanoparticles under visible light

Alumina coating with TiO2and its effect on catalytic photodegradation of phenol andp-cresol

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Alumina coating with TiO₂and its effect on catalytic photodegradation of phenol andp-cresol