Facile one-pot synthesis of MoS2 quantum dots–graphene–TiO2 composites for highly enhanced photocatalytic properties

2015 ◽  
Vol 51 (9) ◽  
pp. 1709-1712 ◽  
Author(s):  
Weiyin Gao ◽  
Minqiang Wang ◽  
Chenxin Ran ◽  
Le Li
Keyword(s):  
Quantum Dots ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Charge Separation ◽  
One Pot ◽  
Composite Photocatalyst ◽  
One Pot Synthesis ◽  
Light Absorbance

We reported a simple one-pot solvothermal approach to fabricate MoS2 quantum dots (QDs)–graphene–TiO2 (MGT) composite photocatalyst with significant improved photocatalysis property, which is caused by the increased charge separation, visible-light absorbance, specific surface area and reaction sites upon the introduction of MoS2 QDs.

scholarly journals Development of a novel photocatalyst for the photocatalytic treatment of industrial wastewater

2021 ◽  
Author(s):  
Mohsen Nasirian
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metal ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mass Ratio ◽  
Thermal Synthesis ◽  
Composite Photocatalyst ◽  
X Ray

Heterogeneous semiconductor photocatalysts have been shown to be efficient for the degradation of refractory organics into simple compounds. Among all photocatalysts, TiO2 is the most used one. Two issues that arise with the use of unmodified TiO2 as a photocatalyst are the unwanted fast recombination of electron/hole pairs and the lower effectiveness in the presence of visible light irradiation. Doping a transition metal or a non-metal into TiO2 and its combination with another photocatalyst have been used to enhance its photoactivity. This study is to develop a new photocatalyst by the combination of TiO2 with another semiconductor oxide (Fe2O3) and its doping with transition metal such as Ag. Combined photocatalysts of Fe2O3 /TiO2 (with different mass ratio of Fe:TiO2) is synthesized and then silver ion is doped to combine photocatalysts (with different mass ratio of Ag:TiO2) to produce a new composite photocatalyst of Ag/TiO2/Fe2O3. A new method of UV-assisted thermal synthesis is also employed to prepare the new composite photocatalyst. Methyl orange (MO) and Congo red (CR), as model pollutants, are used to test the developed photocatalyst. In addition, nitrogen-doped titanium dioxide photocatalyst (N-TiO2) with heterojunction structures is synthesized by three different approaches including new UV-assisted thermal synthesis, annealing, and microwave techniques. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method to prepare N-TiO2 at lower temperature and atmospheric pressure as well as a lower cost. Design of Experiment (DOE) along with response surface methodology (RSM) is used to optimize the photocatalytic activity of N-TiO2 as well as the affecting parameters (wavelength, light intensity, pH, and initial TOC) for decomposition of organics. The structure of all synthesized composite photocatalysts are investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) is employed to evaluate surface characteristics and elemental analysis of synthesized photocatalysts. Specific surface area of photocatalysts is measured based on Brunauer, Emmett and Teller (BET) technique. Results show that bare TiO2 has the lowest photocatalytic activity in degradation of organics. When silver is doped to TiO2, the degradation of MO is slightly enhanced at specific mass ratio. The presence of Fe2O3 in the new composite causes a red shift and enhances the potential to absorb higher range of visible light. Results from XRD confirmed that Fe3+ substitutes with Ti4+ in the crystal lattice of TiO2 and crystal defect occurs. The degradation of MO in presence of Ag/TiO2/Fe2O3 (Ag/TiO2=0.005 w:w and Fe:TiO2= 0.01 w:w) reached to 95.6% under sunlight in three hours with a red shift towards visible light. It is observed that there is an optimum specific surface area of photocatalysts by doping and combining photocatalysts.

One-Pot Fabrication of K-Doped g-C3N4/SiO2Composite with Enhanced Photocatalytic Activity for Degradation of Tetracycline

2021 ◽  
Vol 43 (2) ◽  
pp. 124-124
Author(s):  
Min keng He Min keng He ◽  
Jin Zhang Jin Zhang ◽  
Fang yan Chen Fang yan Chen ◽  
Ke keShu Ke keShu ◽  
Yu bin Tang Yu bin Tang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Contaminants ◽  
Raw Materials ◽  
Thermal Polymerization ◽  
One Pot

K-doped g-C3N4/SiO2composite (SiO2/K-CN) was synthesized by a facile thermal polymerization with potassium chloride, melamine and nano-silica as raw materials. The as-prepared SiO2/K-CN was characterized by various measures. The photocatalytic activity of SiO2/K-CN was tested via the photocatalytic degradation of tetracycline under visible-light irradiation. The results showed that the specific surface area of SiO2/K-CN catalyst was 28.16m2/g, which is larger than that of pristine K-doped g-C3N4. Both K-doping and silica-combination can reduce the recombination rate of photo-generated electrons-holes pairs and broaden the region of visible light-harvesting. Compared with the pristine K-doped g-C3N4 and composite SiO2/g-C3N4, SiO2/K-CN exhibits distinctly higher photocatalytic activity for degradation of tetracycline. The enhanced photocatalytic performance of SiO2/K-CN is attributed to the increased specific surface area and the synergistic effect of K-doping and silica-combination in both accelerating separation of charged carries and improving visible light-absorption. During photocatalytic degradation of tetracycline, superoxide radicals play the most important role, followed by holes.SiO2/K-CN complex has excellent stability and shows promising application in photocatalytic degradation of organic contaminants in water.

scholarly journals Development of a novel photocatalyst for the photocatalytic treatment of industrial wastewater

2021 ◽  
Author(s):  
Mohsen Nasirian
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metal ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mass Ratio ◽  
Thermal Synthesis ◽  
Composite Photocatalyst ◽  
X Ray

Heterogeneous semiconductor photocatalysts have been shown to be efficient for the degradation of refractory organics into simple compounds. Among all photocatalysts, TiO2 is the most used one. Two issues that arise with the use of unmodified TiO2 as a photocatalyst are the unwanted fast recombination of electron/hole pairs and the lower effectiveness in the presence of visible light irradiation. Doping a transition metal or a non-metal into TiO2 and its combination with another photocatalyst have been used to enhance its photoactivity. This study is to develop a new photocatalyst by the combination of TiO2 with another semiconductor oxide (Fe2O3) and its doping with transition metal such as Ag. Combined photocatalysts of Fe2O3 /TiO2 (with different mass ratio of Fe:TiO2) is synthesized and then silver ion is doped to combine photocatalysts (with different mass ratio of Ag:TiO2) to produce a new composite photocatalyst of Ag/TiO2/Fe2O3. A new method of UV-assisted thermal synthesis is also employed to prepare the new composite photocatalyst. Methyl orange (MO) and Congo red (CR), as model pollutants, are used to test the developed photocatalyst. In addition, nitrogen-doped titanium dioxide photocatalyst (N-TiO2) with heterojunction structures is synthesized by three different approaches including new UV-assisted thermal synthesis, annealing, and microwave techniques. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method to prepare N-TiO2 at lower temperature and atmospheric pressure as well as a lower cost. Design of Experiment (DOE) along with response surface methodology (RSM) is used to optimize the photocatalytic activity of N-TiO2 as well as the affecting parameters (wavelength, light intensity, pH, and initial TOC) for decomposition of organics. The structure of all synthesized composite photocatalysts are investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) is employed to evaluate surface characteristics and elemental analysis of synthesized photocatalysts. Specific surface area of photocatalysts is measured based on Brunauer, Emmett and Teller (BET) technique. Results show that bare TiO2 has the lowest photocatalytic activity in degradation of organics. When silver is doped to TiO2, the degradation of MO is slightly enhanced at specific mass ratio. The presence of Fe2O3 in the new composite causes a red shift and enhances the potential to absorb higher range of visible light. Results from XRD confirmed that Fe3+ substitutes with Ti4+ in the crystal lattice of TiO2 and crystal defect occurs. The degradation of MO in presence of Ag/TiO2/Fe2O3 (Ag/TiO2=0.005 w:w and Fe:TiO2= 0.01 w:w) reached to 95.6% under sunlight in three hours with a red shift towards visible light. It is observed that there is an optimum specific surface area of photocatalysts by doping and combining photocatalysts.

One-step synthesis of spherical NaTaO3 and graphene spherical NaTaO3 nanoparticles with enhanced photocatalytic activity for NO purification

2018 ◽  
Vol 11 (04) ◽  
pp. 1850070 ◽  
Author(s):  
Zimao Ding ◽  
Sheng Guo ◽  
Xiaoyong Wu ◽  
Hussain Fida
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Uv Irradiation ◽  
Mixed Solution ◽  
One Pot ◽  
Photocatalytic Ability ◽  
Water Glycerol

To obtain efficient photocatalytic air purification, a series of NaTaO3 nanoparticles were successfully synthesized through a one-pot solvothermal approach, using water/glycerol mixed solution as solvent. The glycerol not only played an important role for controlling the morphology and particle size, but also remarkably enhanced the specific surface area of the as-prepared NaTaO3. Under optimal conditions, the spherical NaTaO3 (NaTaO3-30) exhibited much higher deNO[Formula: see text] performance under UV irradiation as compared to the cubic NaTaO3 (NaTaO3-0). Furthermore, the graphene spherical NaTaO3 composites were also prepared to further enhance the visible light driven photocatalytic ability of spherical NaTaO3. When 1[Formula: see text]wt.% graphene was loaded, the spherical NaTaO3/graphene showed excellent performance for continuous NO gas destruction under UV irradiation, short wavelength visible light ([Formula: see text][Formula: see text]nm) and even long wavelength visible light ([Formula: see text][Formula: see text]nm), which was superior to spherical NaTaO3 and cubic NaTaO3/graphene. The increased specific surface area, expanded light absorption and accelerated electron transport were responsible for the enhanced photocatalytic activity of the composite. The present work may shed new light on the synthesis of novel perovskite-type NaTaO3-based catalysts with excellent photocatalytic performance.

One-pot synthesis of Fe2O3/Y2O3@TNS for enhanced photocatalytic and adsorption properties

2020 ◽  
Vol 44 (38) ◽  
pp. 16370-16383
Author(s):  
Pei Wu ◽  
Xiaona Zhao ◽  
Chunhe Li ◽  
Minchen Yang ◽  
Guojun Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Hydrothermal Method ◽  
Surface Area ◽  
Specific Surface Area ◽  
Adsorption Properties ◽  
Large Specific Surface Area ◽  
Laminar Structure ◽  
One Pot ◽  
One Pot Synthesis

TiO2-based nanosheets (TNS) modified with Fe2O3 and Y2O3 particles (Fe2O3/Y2O3@TNS), possessing a laminar structure with large specific surface area of 382 m2 g−1, were synthesized via a one-pot hydrothermal method.

scholarly journals Synthesis of Au-decorated three-phase-mixed TiO2/phosphate modified active carbon nanocomposites as easily-recycled efficient photocatalysts for degrading high-concentration 2,4-DCP

RSC Advances ◽  
2019 ◽  
Vol 9 (66) ◽  
pp. 38414-38421 ◽  
Author(s):  
Sharafat Ali ◽  
Zhijun Li ◽  
Wajid Ali ◽  
Ziqing Zhang ◽  
Mingzhuo Wei ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Carbon ◽  
Charge Separation ◽  
High Concentration ◽  
Carbon Nanocomposites ◽  
Three Phase

Au decorated three-phase-mixed nanosized TiO2 coupled with phosphate-treated AC as recyclable nanocomposite photocatalysts exhibit excellent photoactivity for degrading high-concentration 2, 4-DCP, mainly due to the improved charge separation and specific surface area.

Facile synthesis of novel Roe-like TiO2 hollow nanospheres with mesoporous cavity for improved photocatalytic activity

2017 ◽  
Vol 10 (03) ◽  
pp. 1750028 ◽  
Author(s):  
Yan Zhu ◽  
Xiaoxia Yan ◽  
Yuanxin Ge ◽  
Shumin Wang ◽  
Dongmei Deng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Charge Separation ◽  
Synergistic Effects ◽  
Assembly Process ◽  
Hollow Nanospheres ◽  
Facile Synthesis

A facile approach was developed to synthesize novel Roe-like TiO2 hollow nanospheres via a template-assisted self-assembly process. These TiO2 nanospheres possessing mesoporous cavity manifest significantly improved photocatalytic activity owing to the synergistic effects of increased charge separation, more efficient use of the light and specific surface area.

Ultrasonic-Microwave Synergistic Synthesis of RGO–Bi2WO6 Photocatalyst with High Photoactivity for Basic Nitrogen Compounds in Light Oil

NANO ◽  
2016 ◽  
Vol 11 (05) ◽  
pp. 1650052 ◽  
Author(s):  
Ying Chen ◽  
Shenglun Ji ◽  
Tengfei Qiao ◽  
Shuang Miao ◽  
Yu Zhao
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Composite Catalyst ◽  
Photogenerated Carrier ◽  
X Ray Diffraction ◽  
Composite Photocatalyst ◽  
Photocatalytic Activities ◽  
Light Oil ◽  
Ft Ir

Graphene–Bi2WO6 composite photocatalyst with excellent photocatalytic properties were synthetized by ultrasonic-microwave synergistic method. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier infrared (FT-IR) spectrum, specific surface area analyzer (BET) and UV-Vis diffuse reflectance spectra. The photocatalytic activities of as-prepared samples were evaluated by degradation of pyridine in light oil under visible light irradiation. The results show that graphene changed appearance structure of Bi2WO6, which prevented the Bi2WO6 nanosheets reunion arrangement, and increased specific surface area of the catalyst. It can also reduce the recombination probability of photogenerated carrier, so as to improve the photocatalytic activity of the composite catalyst. The optimal amount of graphene is 2%, with the denitrification rate as high as 89.28%, much higher than that of pure Bi2WO6.

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