Reduced Graphene Oxide/TiO2 Nanocomposite: From Synthesis to Characterization for Efficient Visible Light Photocatalytic Applications

Rommozzi, Elena; Zannotti, Marco; Giovannetti, Rita; D’Amato, Chiara Anna; Ferraro, Stefano; Minicucci, Marco; Gunnella, R.; Cicco, Andrea Di

doi:10.3390/catal8120598

Cited by 57 publications

(27 citation statements)

References 44 publications

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“…By observing the curve of 1%, 3%, and 5% rGO-P25, it is obvious that the Ti-O-Ti absorption peak was weakened in composite catalysts; this may be the result of the combination of TiO 2 and graphene. Furthermore, the observed enhancement of the absorption band at 1621 cm −1 could be attributable to skeletal vibration of the graphene [48]. The presence of GO in the 1% rGO-P25 composite catalyst was confirmed by these results [49].…”

Section: Introductionsupporting

confidence: 55%

Reduced Graphene Oxide–P25 Nanocomposites as Efficient Photocatalysts for Degradation of Bisphenol A in Water

Bai

Yang

et al. 2019

Catalysts

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Reduced graphene oxide-titanium dioxide photocatalyst (rGO-TiO 2 ) was successfully synthesized by the hydrothermal method. The rGO-TiO 2 was used as photocatalyst for the degradation of bisphenol A (BPA), which is a typical endocrine disruptor of the environment. Characterization of photocatalysts and photocatalytic experiments under different conditions were performed for studying the structure and properties of photocatalysts. The characterization results showed that part of the anatase type TiO 2 was converted into rutile type TiO 2 after hydrothermal treatment and 1% rGO-P25 had the largest specific surface area (52.174 m 2 /g). Photocatalytic experiments indicated that 1% rGO-P25 had the best catalytic effect, and the most suitable concentration was 0.5 g/L. When the solution pH was 5.98, the catalyst was the most active. Under visible light, the three photocatalytic mechanisms were ranked as follows:1% rGO-P25 also had strong photocatalytic activity in the photocatalytic degradation of BPA under sunlight irradiation. 1% rGO-P25 with 0.5 g/L may be a very promising photocatalyst with a variety of light sources, especially under sunlight for practical applications.Catalysts 2019, 9, 607 2 of 15 out under normal temperature and pressure [10]; modern production cleaning process, where the energy source of this process is solar energy that cannot cause secondary pollution, and organic matter can be mineralized into clean energy such as H 2 O and CO 2 [11]; fast reaction rate, where organic pollutants can be destroyed completely within minutes to hours [12]. However, some drawbacks limit the practical application of TiO 2 . For instance, fast h + /e − recombination [13]; the large bandgap energy of 3.2 eV can only be excited by ultraviolet light (UV) with a wavelength less than 387 nm [3,6,[14][15][16][17]. In recent years, scientists have advanced many strategies in order to further improve the photocatalytic performance of TiO 2 , such as doping with non-metallic elements, combining with metal ions, depositing noble metals, and creating heterojunctions with other semiconductors [12,[18][19][20][21][22]. More recently, in contrast to other materials, graphene, graphene oxide (GO), and the graphene monolith formed by the stripping of GO, reduced graphene oxide (rGO) used in this experiment received wider attention because of its good mechanical strength, high electron mobility, chemical stability, optical properties, and high surface area [23][24][25][26][27]. Among them, rGO is a derivative of graphene and has a unique sp 2 hybrid carbon network [28]. The surface of the relatively inert graphene becomes extremely active due to the introduction of a large number of oxygen-containing functional groups such as hydroxyl group, epoxy group, carbonyl group, and a carboxyl group [29,30]. Therefore, the surface of graphene can also be connected to specific functions such as biomolecules, polymers, and inorganic particles [31]. The photocatalytic enhancement of rGO-TiO 2 composites can be attributed to three aspects: fi...

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Section: Introductionsupporting

confidence: 55%

Reduced Graphene Oxide–P25 Nanocomposites as Efficient Photocatalysts for Degradation of Bisphenol A in Water

Bai

Yang

et al. 2019

Catalysts

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“…The effective utilization of TiO 2 is hindered by its large bandgap (3–3.2 eV) and activation requirements in the UV region of the spectrum. Thus it is essential to tune the bandgap of TiO 2 into the visible area [ 12 ] through modification of the TiO 2 lattice structure [ 13 , 14 , 15 ]. Generally, heterogeneous photocatalysis follows the advance oxidation process at the surface of a semiconductor through the absorption of photons, which cause electron excitation from the valance band to the conduction band, and this charge separation leads to the generation of free radicals.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Decolorization and Biocidal Applications of Nonmetal Doped TiO2: Isotherm, Kinetic Modeling and In Silico Molecular Docking Studies

et al. 2020

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Textile dyes and microbial contamination of surface water bodies have been recognized as emerging quality concerns around the globe. The simultaneous resolve of such impurities can pave the route for an amicable technological solution. This study reports the photocatalytic performance and the biocidal potential of nitrogen-doped TiO2 against reactive black 5 (RB5), a double azo dye and E. coli. Molecular docking was performed to identify and quantify the interactions of the TiO2 with β-lactamase enzyme and to predict the biocidal mechanism. The sol-gel technique was employed for the synthesis of different mol% nitrogen-doped TiO2. The synthesized photocatalysts were characterized using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) and diffuse reflectance spectroscopy (DRS). The effects of different synthesis and reaction parameters were studied. RB5 dye degradation was monitored by tracking shifts in the absorption spectrum and percent chemical oxygen demand (COD) removal. The best nanomaterial depicted 5.57 nm crystallite size, 49.54 m2 g−1 specific surface area, 11–40 nm particle size with spherical morphologies, and uniform distribution. The RB5 decolorization data fits well with the pseudo-first-order kinetic model, and the maximum monolayer coverage capacity for the Langmuir adsorption model was found to be 40 mg g−1 with Kads of 0.113 mg−1. The LH model yielded a higher coefficient KC (1.15 mg L−1 h−1) compared to the adsorption constant KLH (0.3084 L mg−1). 90% COD removal was achieved in 60 min of irradiation, confirmed by the disappearance of spectral peaks. The best-optimized photocatalysts showed a noticeable biocidal potential against human pathogenic strain E. coli in 150 min. The biocidal mechanism of best-optimized photocatalyst was predicted by molecular docking simulation against E. coli β-lactamase enzyme. The docking score (−7.6 kcal mol−1) and the binding interaction with the active site residues (Lys315, Thr316, and Glu272) of β-lactamase further confirmed that inhibition of β-lactamase could be a most probable mechanism of biocidal activity.

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“…After hybridizing with TiO2, a drastically decreased PL intensity can be observed in TNT, indicating the formation of heterojunction can effectively accelerate the separation of photogenerated electrons and holes. After The photoluminescence (PL) technique has been widely employed to investigate the migration, transfer, and recombination process of photoinduced electrons and holes in semiconductors [42,43]. The high emission intensity indicates the fast recombination rate of electron-hole pairs.…”

Section: Photocatalytic Mechanism Discussionmentioning

confidence: 99%

N-Doped K3Ti5NbO14@TiO2 Core-Shell Structure for Enhanced Visible-Light-Driven Photocatalytic Activity in Environmental Remediation

Gao

Wang

et al. 2019

Catalysts

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A novel N-doped K3Ti5NbO14@TiO2 (NTNT) core-shell heterojunction photocatalyst was synthesized by firstly mixing titanium isopropoxide and K3Ti5NbO14 nanobelt, and then calcinating at 500 °C in air using urea as the nitrogen source. The samples were analyzed by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopic (XPS) spectra. Anatase TiO2 nanoparticles were closely deposited on the surface of K3Ti5NbO14 nanobelt to form a nanoscale heterojunction structure favorable for the separation of photogenerated charge carriers. Meanwhile, the nitrogen atoms were mainly doped in the crystal lattices of TiO2, resulting in the increased light harvesting ability to visible light region. The photocatalytic performance was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The enhanced photocatalytic activity of NTNT was ascribed to the combined effects of morphology engineering, N doping and the formation of heterojunction. A possible photocatalytic mechanism was proposed based on the experimental results.

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Reduced Graphene Oxide/TiO2 Nanocomposite: From Synthesis to Characterization for Efficient Visible Light Photocatalytic Applications

Cited by 57 publications

References 44 publications

Reduced Graphene Oxide–P25 Nanocomposites as Efficient Photocatalysts for Degradation of Bisphenol A in Water

Reduced Graphene Oxide–P25 Nanocomposites as Efficient Photocatalysts for Degradation of Bisphenol A in Water

Photocatalytic Decolorization and Biocidal Applications of Nonmetal Doped TiO2: Isotherm, Kinetic Modeling and In Silico Molecular Docking Studies

N-Doped K3Ti5NbO14@TiO2 Core-Shell Structure for Enhanced Visible-Light-Driven Photocatalytic Activity in Environmental Remediation

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