scholarly journals Preparation of Nitrogen-Doped Mesoporous TiO2/RGO Composites and Its Application to Visible Light-Assisted Photocatalytic Degradation

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xin Wen ◽  
Siqin Zhao ◽  
S. Asuha
Keyword(s):  
Graphene Oxide ◽  
Methyl Orange ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Anatase Phase ◽  
Methyl Orange Solution ◽  
Nitrogen Doped ◽  
Orange Solution

A series of nitrogen-doped mesoporous TiO2 nanomaterials and nitrogen-doped mesoporous TiO2/reduced graphene oxide (RGO) composites were successfully prepared by hydrothermal method using triammonium citrate as the nitrogen source. The effects of nitrogen and graphene oxide (GO) dopping on the photocatalytic properties of the TiO2 were investigated to optimize preparation conditions. The results showed that all prepared samples were mainly composed of the anatase phase and possessed a mesoporous structure. The use of the triammonium citrate not only significantly increased the specific surface area of the synthesized samples but also caused the partial reduction of GO to RGO, leading to further increase of the specific surface area and the improvement of quantum efficiency of the photogenerated electrons. All synthesized samples showed superior photocatalytic performance for methyl orange solution. Among them, the NMT/RGO-1.8-10 was found to be the best; the degradation rate of methyl orange solution on the sample reached 100% in 30 minutes under visible light irradiation.

scholarly journals Enhanced Photocatalytic Activity for Degradation of Methyl Orange over Silica-Titania

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Yaping Guo ◽  
Shaogui Yang ◽  
Xuefei Zhou ◽  
Chunmian Lin ◽  
Yajun Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Anatase Phase ◽  
Solution Treatment ◽  
X Ray

Silica-modified titania (SMT) powders with different atomic ratios of silica to titanium (Rx) were successfully synthesized by a simple ultrasonic irradiation technique. The prepared samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet visible spectroscopy. The specific surface area was measured according to BET theory. Results indicate that the addition of silica to titania can suppress the crystalline size growth and the transformation of anatase phase to rutile phase of titania, enlarge specific surface area of the titania particles, and result in a blue shift of absorption edge compared to pure titania. The photocatalytic activity of the SMT samples was evaluated by decolorizing methyl orange aqueous solutions under UV-visible light irradiation. It was found in our study that this activity was affected by silica content, calcination temperature, H2SO4, and oxidants such as KIO4, (NH4)2S2O8and H2O2. The results reveal that the photocatalytic activity of 0.1-SMT catalyst is the best among all samples calcined at550°C for 1 h and it is 1.56 times higher than that of Degussa P-25 titania, which is a widely used commercial TiO2made by Germany Degussa company and has been most widely used in industry as photocatalyst, antiultraviolet product, and thermal stabilizer. The optimal calcination temperature for preparation was550°C. The photocatalytic activity of SMT samples is significantly enhanced by H2SO4solution treatment and oxidants.

scholarly journals Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI) in Water

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Xiao ◽  
Wenjie Zhou ◽  
Yanhua Zhang ◽  
Liangliang Tian ◽  
Hongdong Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
Reduced Graphene ◽  
Visible Light Driven

A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO) hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI) in water. Over 95% of Cr(VI) was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5) and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

scholarly journals Preparation of Chitosan—Graphene Oxide Composite Aerogel by Hydrothermal Method and Its Adsorption Property of Methyl Orange

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2169
Author(s):  
Wei Zhu ◽  
Xueliang Jiang ◽  
Fangjun Liu ◽  
Feng You ◽  
Chu Yao
Keyword(s):  
Graphene Oxide ◽  
Methyl Orange ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Hydrothermal Method ◽  
Surface Area ◽  
Specific Surface Area ◽  
Adsorption Property ◽  
High Porosity ◽  
Composite Aerogel

Graphene based aerogel has become one of the most likely functional adsorption materials that is applicable to purify various contaminated water sources, such as dye wastewater, because of its high porosity, structural stability, large specific surface area, and high adsorption capacity. In this study, chitosan and graphene oxide were first selected as the matrix to prepare the composite hydrogel through the hydrothermal method, which was further frozen and dried to obtain the target aerogel. The microscopic structures and adsorption capacity of the composite aerogel were then characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 (nitrogen) physical adsorption and desorption tests. The results show that the specific surface area of the composite aerogel was reached at 297.431 m2/g, which is higher than that of graphene oxide aerogel and chitosan aerogel. The aperture was reduced to about 3 nm. The adsorption rate of the composite aerogel for the methyl orange solution was as high as 97.2% at pH = 1, and the adsorption capacity was 48.6 mg/g. The adsorption process of the composite aerogel satisfies the Langmuir equation and can be described by the second-order adsorption kinetics. In addition, it is worth noting that this composite aerogel can provide a striking adsorption characteristic on methyl orange due to the combining effects from massive amino groups on chitosan and the structural conjugation of graphene oxide.

scholarly journals Graphene Oxide Hybridised TiO2 for Visible Light Photocatalytic Degradation of Phenol

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1420 ◽  
Author(s):  
Guanyu Wang ◽  
Weijie Guo ◽  
Deping Xu ◽  
Di Liu ◽  
Mengtao Qin
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Phenol Solution ◽  
X Ray

In industrial pollutants, phenol is a kind of degradation-resistant hazardous compound. It is generated during industrial processes in factories and treatment at sewage plants. In this study, we analyse the photocatalytic activity of TiO2 and rGO as a composite for the degradation of phenol. Hybridised titanium dioxide/reduced graphene oxide (TiO2/rGO) nanocomposites were synthesised by a simple hydrothermal method using flake graphite and tetrabutyl titanate as raw materials. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) specific area analysis, Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), photoelectrochemical analysis, and UV–vis diffuse reflectance spectra (DRS) were employed to characterise the physicochemical properties of the as-prepared nanocomposites. The results showed the TiO2/rGO nanocomposites’ significant anatase phase and a small fraction of the rutile phase the same as that of the as-prepared TiO2 nanoparticles. The spherical TiO2 nanoparticles (diameter 20–50 nm) were agglomerated slightly and the agglomerates were anchored on the rGO sheets and dispersed symmetrically. The specific surface area of TiO2/rGO-4% nanocomposites was 156.4 m2/g, revealing a high specific surface area. Oxygen-containing functional groups that existed in TiO2/rGO-4% nanocomposites were almost removed during hydrothermal processing. The photocurrent response of TiO2/rGO-4% was strongest among the TiO2/rGO nanocomposites, and the bandgap of TiO2/rGO-4% was 2.91 eV, showing a redshift of absorption into the visible region, which was in favour of the high photocatalytic activity of TiO2/rGO nanocomposites under visible light (λ > 420 nm). Moreover, the samples were employed to photodegrade phenol solution under visible light irradiation. TiO2/rGO-4% nanocomposite degraded the phenol solution up to 97.9%, and its degradation rate constant was 0.0190 h−1, which had higher degradation activity than that of other TiO2/rGO nanocomposites. This is a promising candidate catalyst material for organic wastewater treatment.

Preparation and Photocatalytic Properties of Nanosized La3+ and Co2+ Co-Doped TiO2 by Microemulsions

2007 ◽  
Vol 336-338 ◽  
pp. 1943-1945
Author(s):  
Wei Liang Liu ◽  
Dan Li Lu ◽  
Chang Chun Ge ◽  
Jian Hua Chen ◽  
Zhi Ping He
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Uv Light ◽  
Pure Tio2 ◽  
Doped Tio2 ◽  
Co Doped

La3+ and Co2+ co-doped titania nanoparticles were prepared from reacting TiOSO4, La(NO3)3 and Co(NO3)2 with NH4OH in water/Triton X-100/n-hexanol/cyclohexane microemulsions. The structure, surface morphology and the specific surface area of the samples were characterized. The photocatalytic efficiency of as-prepared TiO2 was tested by photodegrading methyl orange. The results showed that doping with La3+ and Co2+ could suppress the growth of TiO2 grains and increase the specific surface area; When the calcination temperature increased from 300°C to 900°C, the average crystallite size of the particles increased from 7.3nm to 35.6 nm andthe specific surface area of the particles decreased rapidly from 205.5m2/g to 41.2m2/g. The synthesized amorphous particles wer transformed into anatase phase at 300°C, and further into rutile phase at 900°C. UV-Vis diffuse reflectance spectrum revealed that La3+ and Co2+ co-doped TiO2 absorbed UV light and visible light, while pure TiO2 could only absorb UV light. In the experiments of photodegrading methyl orange, it was proved that La3+ and Co2+ co-doped TiO2 had high photocatalytic activity under UV light and visible light, while pure TiO2 showed photocatalytic activity just under UV light.

Coassembly and high ORR performance of monodisperse Pt nanocrystals with a mesopore-rich nitrogen-doped graphene aerogel

2017 ◽  
Vol 5 (33) ◽  
pp. 17544-17548 ◽  
Author(s):  
Beibei Xie ◽  
Yong Zhang ◽  
Renjie Zhang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Large Specific Surface Area ◽  
Graphene Aerogel ◽  
N Content ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Pt Nanocrystals

Monodisperse Pt nanocrystals in NGA with a large specific surface area and high N content yield high ORR performance.

Synthesis of reduced graphene oxide/aluminum nanocomposites via chemical-mechanical processes

2018 ◽  
Vol 52 (22) ◽  
pp. 3015-3025 ◽  
Author(s):  
Daeyoung Kim ◽  
Heon Kang ◽  
Donghyun Bae ◽  
Seungjin Nam ◽  
Manuel Quevedo-Lopez ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aluminum Powder ◽  
Mechanical Milling ◽  
Uniform Dispersion ◽  
Reduced Graphene

The present study employed a combination of solution-based synthesis and mechanical milling to develop reduced graphene oxide/aluminum composites, in order to achieve uniform dispersion of reduced graphene oxide and strong interfaces between reduced graphene oxide and aluminum. First, spherical aluminum powder was flattened via mechanical milling to afford a large specific surface area and many reaction sites for the graphene oxide. A hydrophilic surface was then created by coating the aluminum powder with polyvinyl alcohol. The polyvinyl alcohol-coated aluminum slurry was mixed with a graphene oxide suspension, thereby inducing a reaction between graphene oxide and polyvinyl alcohol via hydrogen bonding. After thermal reduction, the composite powder was further ball milled and hot-pressed at 500℃ to produce a reduced graphene oxide/aluminum composite. The dispersion of reduced graphene oxide in the composite, as well as the mechanical and thermal behaviors of the composite, improved with increased flattening and specific surface area of the starting aluminum powder.

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