Photocatalyst separation from aqueous dispersion using graphene oxide/TiO2 nanocomposites

“…20 Metal or metal oxides (Ag, Au, TiO 2 and SnO 2 ) are combined with graphene and the resultant hybridized materials exhibit superior photocatalytic properties than the bulk metal or metal oxide. 24,25 The better solubility of GO in water and other solvents allows to ease their deposition onto the surface of metal/metal oxides. 23 On the other hand, graphene oxide (GO) is a layer-structured graphite compound built up by hydrophilic, stacked graphene sheets bound to oxygen in the form of carboxyl, hydroxyl or epoxy groups.…”

Section: Introductionmentioning

confidence: 99%

Graphene oxide and Ag engulfed TiO₂ nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance

et al. 2014

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were investigated using the composite of Ag nanoparticles (Ag NPs) and graphene oxide (GO) deposited over TiO 2 nanotube arrays (TNTs). The resulting TNTs in the composite showed 100% anatase phase with no occurrence of the rutile phase. An implicit microscopic and spectroscopic technique (FESEM, HRTEM, FTIR and Raman analysis) confirmed the presence of Ag NPs and GO in the composite photocatalyst. It also exhibited an evident shift of the absorption edge in the visible range. The successful depositions of Ag contributed to improved photocatalytic activity in the visible spectrum owing to the existence of localized surface plasmon resonance (LSPR), and further the deposition of GO minimized the recombination of electron-hole pairs. The photocatalytic degradation of both MB and 2-CP followed pseudo-second order kinetics. In the primary run, both MB and 2-CP exhibited almost similar degradation efficiency of 68.3 and 66.8%, respectively. The reusability studies showed a deprived performance for MB degradation than that of 2-CP, due to chemisorption of MB. The prepared composite exhibited significantly larger enhancement in the photocatalytic oxidation of pollutants with greater electrons mobility to reactive sites of GO and Ag. 03 7967 5318; Tel: +60 03 7967 7678 † Electronic supplementary information (ESI) available: FTIR spectra of GO-Ag-TNTs before and aer the adsorption of MB, photocatalytic degradation kinetic parameters and kinetic plots of rst order and second order. SeeFig. 7 (a) Photoluminescence spectra of TNTs, Ag-TNTs and GO-Ag-TNTs. Core level XPS spectra of (b) Ti 2p (c) Ag 3d and (d) C 1s of GO-Ag-TNTs.This journal is

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“…The catalyst recovery can be achieved through aggregation and subsequent sedimentation followed by filtration of the titanate compounds, or through their deposition on appropriate materials. [16] The type of liquid-phase aggregation of the nanoparticles has a significant effect on the textural properties such as the porosity, pore-size distribution, and mechanical stability of different solution casts, for example, dip-coated, screen-printed, and doctor-bladed functional coatings. [3] Importantly, the nanoand micron-scale structure of the aggregates greatly influences their level of toxicity, and hence, their potential impact on human health and the environment.…”

Section: Introductionmentioning

confidence: 99%

Dispersion Characteristics and Aggregation in Titanate Nanowire Colloids

et al. 2014

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Titanate nanowires (TiONWs) are synthesized through the hydrothermal method and characterized in acidic aqueous dispersions by using electrophoresis, dynamic light scattering, and atomic force microscopy. The TiONWs have a rodlike shape with an average length of about 600 nm and a thickness of 35 nm. They are positively charged under the conditions used. Their surface charge properties and aggregation are investigated in the presence of oppositely charged poly(styrene sulfonate) (PSS) polyelectrolyte. Charge neutralization followed by a subsequent charge reversal process is observed, which is attributed to the adsorption of PSS. The colloids are unstable near the charge neutralization point and stable at lower and higher PSS doses, in good qualitative agreement with the theory developed by Derjaguin, Landau, Verwey, and Overbeek (DLVO). The nanowires prefer to align along the walls, leading to “spaghetti‐like” oriented aggregates. The aggregation processes of bare and PSS‐coated TiONWs are monitored at different concentrations of an inert electrolyte; slow aggregation is found at low salt levels, whereas aggregation is rapid beyond the critical coagulation concentration, as predicted by the DLVO theory, which describes the colloid stability of the TiONWs adequately in all the systems investigated. Coating of the nanowires with the polyelectrolyte leads to a critical coagulation concentration 75 times higher than that of the bare titanates, indicating the enormous stabilizing effect of PSS.

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Photocatalyst separation from aqueous dispersion using graphene oxide/TiO2 nanocomposites

Cited by 50 publications

References 36 publications

Employing TiO 2 photocatalysis to deal with landfill leachate: Current status and development

Employing TiO 2 photocatalysis to deal with landfill leachate: Current status and development

Graphene oxide and Ag engulfed TiO₂ nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance

Dispersion Characteristics and Aggregation in Titanate Nanowire Colloids

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Photocatalyst separation from aqueous dispersion using graphene oxide/TiO2 nanocomposites

Cited by 50 publications

References 36 publications

Employing TiO 2 photocatalysis to deal with landfill leachate: Current status and development

Employing TiO 2 photocatalysis to deal with landfill leachate: Current status and development

Graphene oxide and Ag engulfed TiO2 nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance

Dispersion Characteristics and Aggregation in Titanate Nanowire Colloids

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Graphene oxide and Ag engulfed TiO₂ nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance