Design of graphene-based TiO2 photocatalysts—a review

Morales‐Torres, Sergio; Pastrana‐Martínez, Luisa M.; Figueiredo, José L.; Silva, Adrián M.T.

doi:10.1007/s11356-012-0939-4

Cited by 271 publications

(109 citation statements)

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“…Like other AOPs such as photocatalysis [3], ozonation [4], catalytic wet air oxidation [5], electrooxidation [6], persulfate oxidation [7], cavitation [8] and the Fenton process [9], CWPO relies on the formation of highly oxidizing hydroxyl radicals (HO%), which subsequently serve as effective species for the destruction of most of the organic pollutants present in aqueous phase [10,11]. In CWPO, HO%are formed from the catalytic decomposition of hydrogen peroxide (H 2 O 2 ).…”

Section: Introductionmentioning

confidence: 99%

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The role of cobalt in bimetallic iron-cobalt magnetic carbon xerogels developed for catalytic wet peroxide oxidation

et al. 2017

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A B S T R A C TThree magnetic carbon xerogels were developed by inclusion of iron and/or cobalt precursors during the synthesis procedure. The synthesized materials were tested in the catalytic wet peroxide oxidation (CWPO) of aqueous solutions containing 4-nitrophenol (4-NP) − a refractory organic model pollutant, under a water treatment process intensification approach. For that purpose, the experimental runs were performed with high pollutant load (5 g L, corresponding to a fixed pollutant/catalyst mass ratio of 2), atmospheric pressure, 50°C, pH = 3 and stoichiometric amount of hydrogen peroxide (H 2 O 2 ).The bimetallic magnetic carbon xerogel catalyst (CX/CoFe) was more active than each of the monometallic catalysts (CX/Fe or CX/Co). The better performance was explained in terms of a synergic association of factors: (i) the enhanced accessibility to the active iron species at the surface of CX/CoFe promoted by the simultaneous incorporation of cobalt, (ii) the ability of metallic Co to catalyse H 2 O 2 decomposition via hydroxyl radicals (HO%) formation, and (iii) the efficient reduction of Fe 3+ to Fe 2+ promoted by metallic Co on the surface of CX/CoFe. A 4-NP conversion of 98.5% was determined after 30 min of CWPO reaction. Leaching of the iron species in the bimetallic CX/CoFe was considerably reduced with relation to the monometallic iron catalyst. However, partial catalyst deactivation occurred due to lower stability of oxidized cobalt species. A detailed reaction mechanism is proposed for the surface catalytic reactions occurring over the CX/CoFe catalyst.

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Section: Introductionmentioning

confidence: 99%

“…), which in turn leads to the undesired production of large amounts of iron sludge in the form of Fe(OH) 3 [9,13]. In this case, the costs associated to the subsequent treatment and disposal of the iron sludge may represent up to 50% of the total operating costs [13].…”

Section: Introductionmentioning

confidence: 99%

The role of cobalt in bimetallic iron-cobalt magnetic carbon xerogels developed for catalytic wet peroxide oxidation

et al. 2017

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“…In the mixing method (M), GO and semiconductors are mixed with stirring and ultrasonication in order to obtain the exfoliation of GO and, successively, GO/TiO 2 product with uniform distribution; in a second step the reduction of GO is performed [51,[172][173][174][175].…”

Section: Preparation Methods Of Gtio 2 Nsmentioning

confidence: 99%

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

et al. 2017

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Synthetic dyes are widely used in textile, paper, food, cosmetic, and pharmaceutical industries. During industrial processes, some of these dyes are released into the wastewater and their successive release into rivers and lakes produces serious environmental problems. TiO 2 is one of the most widely studied and used photocatalysts for environmental remediation. However, it is mainly active under UV-light irradiation due to its band gap of 3.2 eV, while it shows low efficiency under the visible light spectrum. Regarding the exploration of TiO 2 activation in the visible light region of the total solar spectrum, the incorporation of carbon nanomaterials, such as graphene, in order to form carbon-TiO 2 composites is a promising area. Graphene, in fact, has a large surface area which makes it a good adsorbent for organic pollutants removal through the combination of electrostatic attraction and π-π interaction. Furthermore, it has a high electron mobility and therefore it reduces the electron-hole pair recombination, improving the photocatalytic activity of the semiconductor. In recent years, there was an increasing interest in the preparation of graphene-based TiO 2 photocatalysts. The present short review describes the recent advances in TiO 2 photocatalyst coupling with graphene materials with the aim of extending the light absorption of TiO 2 from UV wavelengths into the visible region, focusing on recent progress in the design and applications in the photocatalytic degradation of synthetic dyes.

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“…Therefore, suppressing the recombination of photo-generated charge carriers, as well as the efficient utilization of visible light, are some of the main challenges to develop economically feasible photocatalytic processes. In order to overcome these shortcomings, various strat-egies have been developed to improve the photocatalytic performance of semiconductor materials, such as the addition of electron donors, metal ion or anion doping, noble metal loading, dye sensitization and fabrication of composite semiconductors (Linsebigler et al, 1995;Morales-Torres et al, 2012).…”

Section: Heterogeneous Photocatalysismentioning

confidence: 99%

An overview on the advanced oxidation processes applied for the treatment of water pollutants defined in the recently launched Directive 2013/39/EU

Ribeiro

Nunes

Pereira

et al. 2015

Environment International

806

319

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Environmental pollution is a recognized issue of major concern since a wide range of contaminants has been found in aquatic environment at ng L −1 to μg L −1 levels.In the year 2000, a strategy was defined to identify the priority substances concerning aquatic ecosystems, followed by the definition of environmental quality standards (EQS) in 2008. Recently it was launched the Directive 2013/39/EU that updates the water framework policy highlighting the need to develop new water treatment technologies to deal with such problem. This review summarizes the data published in the last decade regarding the application of advanced oxidation processes (AOPs) to treat priority compounds and certain other pollutants defined in this Directive, excluding the inorganic species (cadmium, lead, mercury, nickel and their derivatives).The Directive 2013/39/EU includes several pesticides

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Design of graphene-based TiO2 photocatalysts—a review

Cited by 271 publications

References 98 publications

The role of cobalt in bimetallic iron-cobalt magnetic carbon xerogels developed for catalytic wet peroxide oxidation

The role of cobalt in bimetallic iron-cobalt magnetic carbon xerogels developed for catalytic wet peroxide oxidation

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

An overview on the advanced oxidation processes applied for the treatment of water pollutants defined in the recently launched Directive 2013/39/EU

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