scholarly journals Synthesis of tetrafluorinated piperidines from nitrones via a visible-light-promoted annelation reaction

2020 ◽  
Vol 16 ◽  
pp. 3104-3108
Author(s):  
Vyacheslav I Supranovich ◽  
Igor A Dmitriev ◽  
Alexander D Dilman
Keyword(s):  
Ascorbic Acid ◽  
Visible Light ◽  
Nucleophilic Substitution ◽  
Blue Light ◽  
Radical Addition ◽  
Intramolecular Nucleophilic Substitution ◽  
Excess Amount ◽  
One Step ◽  
The One

A method for the one-step construction of 3,3,4,4-tetrafluorinated piperidines from nitrones and readily accessible tetrafluorinated iodobromobutane is described. The reaction requires an excess amount of ascorbic acid as the terminal reductant and is performed in the presence of an iridium photocatalyst activated by blue light. The annelation is a result of a radical addition at the nitrone, intramolecular nucleophilic substitution, and reduction of the N–O bond.

Determination of Ascorbic Acid Based on a Platinum Nanoparticles Modified Au Electrode

2011 ◽  
Vol 110-116 ◽  
pp. 1732-1735
Author(s):  
Jia Hong He ◽  
Qiang Xu ◽  
Zhong Rong Song ◽  
Hai Yan Kuang
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Platinum Nanoparticles ◽  
Reaction System ◽  
Au Electrode ◽  
Transmission Electron ◽  
Growth Method ◽  
One Step ◽  
The One

A Platinum nanoparticles modified Au electrode has been successfully fabricated by using an in situ growth method. In this method, the Platinum nanoparticles could be grown on the Au electrode surface via the one-step immersion into the mixture of H2PtCl6 (analytical grade, 1g/L), NaBH4 (analytical grade) and polyvinylpyrrolidone K30 (PVP, analytical grade). A certain amount of PVP was added into the reaction system to prevent the coagulation of the Platinum nanoparticles, which obtained by the chemical redox reaction of H2PtCl6 and NaBH4. The structures and morphologies of the Platinum nanoparticles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) . The direct electrochemical behavior of ascorbic acid in 0.3 mol/L NaCl medium at the Platinum nanoparticles modified electrode has been investigated in detail. Compared to a bare Au electrode, a substantial decrease in the overvoltage of the ascorbic acid was observed at the Platinum nanoparticles modified electrode with oxidation starting at ca. 0.20 V vs. SCE (saturated KCl). At an applied potential of 0.18V, this modified electrode produced high and reproducible sensitivity to ascorbic acid and linear responses were obtained over a concentration range from 0.600 to 3.267 μmol/L with a detection limit of 1.9 nmol/L(S/N=3). The fabrication method of this sensor, which has highly sensitive, low working potential, and fast amperometric sensing to ascorbic acid, is simple and without using complex equipment. In addition, the sensor has been successfully used to detect ascorbic acid in real sample, thus is promising for the future development of ascorbic acid sensors.

Determination of Ascorbic Acid Based on a Platinum Nanoparticles Modified Au Electrode

2013 ◽  
Vol 562-565 ◽  
pp. 813-816
Author(s):  
Jia Hong He ◽  
Zhi Qiang Gao ◽  
Zhong Rong Song
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Platinum Nanoparticles ◽  
Reaction System ◽  
Au Electrode ◽  
Transmission Electron ◽  
Growth Method ◽  
One Step ◽  
The One

A Platinum nanoparticles modified Au electrode has been successfully fabricated by using an in situ growth method. In this method, the Platinum nanoparticles could be grown on the Au electrode surface via the one-step immersion into the mixture of H2PtCl6 (analytical grade, 1g/L), NaBH4 (analytical grade) and polyvinylpyrrolidone K30 (PVP, analytical grade). A certain amount of PVP was added into the reaction system to prevent the coagulation of the Platinum nanoparticles, which obtained by the chemical redox reaction of H2PtCl6 and NaBH4. The structures and morphologies of the Platinum nanoparticles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) . The direct electrochemical behavior of ascorbic acid in 0.3 mol/L NaCl medium at the Platinum nanoparticles modified electrode has been investigated in detail. Compared to a bare Au electrode, a substantial decrease in the overvoltage of the ascorbic acid was observed at the Platinum nanoparticles modified electrode with oxidation starting at ca. 0.20 V vs. SCE (saturated KCl). At an applied potential of 0.18V, this modified electrode produced high and reproducible sensitivity to ascorbic acid and linear responses were obtained over a concentration range from 0.600 to 3.267 μmol/L with a detection limit of 1.9 nmol/L(S/N=3). The fabrication method of this sensor, which has highly sensitive, low working potential, and fast amperometric sensing to ascorbic acid, is simple and without using complex equipment. In addition, the sensor has been successfully used to detect ascorbic acid in real sample, thus is promising for the future development of ascorbic acid sensors.

scholarly journals One-Step Construction of Multi-Walled CNTs Loaded with Alpha-Fe2O3 Nanoparticles for Efficient Photocatalytic Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2820
Author(s):  
Jianle Xu ◽  
Qiang Wen ◽  
Xiao Zhang ◽  
Yinhui Li ◽  
Zeyue Cui ◽  
...  
Keyword(s):  
Visible Light ◽  
High Efficiency ◽  
Separation Efficiency ◽  
Dye Degradation ◽  
Step Method ◽  
Visible Light Photocatalyst ◽  
Defect Sites ◽  
Multi Walled Carbon Nanotubes ◽  
One Step ◽  
The One

The aggregation and the rapid restructuring of the photoinduced electron−hole pairs restructuring in the process of photoelectric response remains a great challenge. In this study, a kind of Multi-walled carbon nanotubes loaded Alpha-Fe2O3 (CNTs/α-Fe2O3) heterostructure composite is successfully prepared via the one-step method. Due to the synergistic effect in the as-prepared CNTs/α-Fe2O3, the defect sites and oxygen-containing functional groups of CNTs can dramatically improve the interface charge separation efficiency and prevent the aggregation of α-Fe2O3. The improved photocurrent and enhanced hole–electron separation rate in the CNTs/α-Fe2O3 is obtained, and the narrower band gap is measured to be 2.8 ev with intensive visible-light absorption performance. Thus, the CNTs/α-Fe2O3 composite serves as an excellent visible light photocatalyst and exhibits an outstanding photocatalytic activity for the cationic dye degradation of rhodamine B (RhB). This research supplies a fresh application area forα-Fe2O3 photocatalyst and initiates a new approach for design of high efficiency photocatalytic materials.

Hydrogen production from formic acid solution by modified TiO2 and titanate nanotubes in a two-step system under visible light irradiation

2014 ◽  
Vol 69 (8) ◽  
pp. 1676-1681 ◽  
Author(s):  
H. M. Yeh ◽  
S. L. Lo ◽  
M. J. Chen ◽  
H. Y. Chen
Keyword(s):  
Hydrogen Production ◽  
Formic Acid ◽  
Visible Light ◽  
Renewable Energy Sources ◽  
Hydrogen Gas ◽  
Titanate Nanotubes ◽  
Formic Acid Solution ◽  
One Step ◽  
The One ◽  
Platinum Loading

Hydrogen gas is one of the most promising renewable energy sources, and the final product of hydrogen combustion is nothing but water. However, it is still a big challenge to produce hydrogen and store it. Many studies have been conducted into produce hydrogen from water using photocatalysts. Z-scheme photocatalysis is a two-photocatalyst system that comprises a hydrogen catalyst and an oxygen catalyst to produce hydrogen and oxygen respectively. Compared to the one-step system, the two-step system can promote the efficiency of water splitting. In addition, formic acid (FA) is a convenient hydrogen-storage material and can be safely handled in aqueous solutions. Therefore, this study investigated the photocatalytic conversion of FA solution to hydrogen using visible light with several types of hydrogen catalysts (CdS/titanate nanotubes (TNTs), CdS/TiO2, Pt/CdS/TNTs) and WO3 as the oxygen catalyst. The results showed that the yield of hydrogen with CdS/TNTs + WO3 was much higher than with CdS/TiO2 + WO3. Moreover, coating the photocatalysts with metal could further promote the reaction. The optimal platinum loading was 0.01 wt%, and the hydrogen production achieved was 852.5 μmol · h−1 with 20 vol% FA solution.

Preparation of Ag-Modified CaBiO2Cl and its Photocatalytic Ability under Visible Light

2014 ◽  
Vol 955-959 ◽  
pp. 120-126
Author(s):  
Ying Feng ◽  
Wei Huang ◽  
Chao Hao Hu ◽  
Wen Zhao ◽  
Pan Fei Jiao ◽  
...  
Keyword(s):  
Visible Light ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Photocatalytic Ability ◽  
Reaction Method ◽  
X Ray ◽  
Photocatalytic Activities ◽  
One Step ◽  
The One ◽  
Scanning Electron

Ag-modified CaBiO2Cl photocatalysts were synthesized by the one-step solid state reaction method. The microstructure and morphology of catalysts were characterized by using X-ray diffraction, Scanning electron microscopy, and Energy dispersive X-ray detector (EDS) techniques. The photocatalytic activities of pure CaBiO2Cl and Ag-CaBiO2Cl catalysts were further evaluated by degrading methylene blue (MB) under visible-light irradiation. The measured UV-vis absorption spectra indicated that the degradation of Ag-modified CaBiO2Cl has been improved by about 12% in comparison with pure CaBiO2Cl. The enhanced photocatalytic activity in Ag-modified CaBiO2Cl can be ascribed to the better morphologies of the composites due to the Ag additive.

scholarly journals One Pot Synthesis of CoTiO3-TiO2 Composite Nanofibers and its Application in Dye Degradation

2021 ◽  
pp. 1597-1607
Author(s):  
M. Shamshi Hassan
Keyword(s):  
Visible Light ◽  
Composite Nanofibers ◽  
Dye Degradation ◽  
Band Gap Energy ◽  
One Pot ◽  
Light Region ◽  
Composite Photocatalysts ◽  
One Step ◽  
Ft Ir ◽  
The One

CoTiO3-TiO2 composite nanofibrous photocatalysts were synthesized by means of the one-step electrospinning method. The samples were characterized by a range of different methods (XRD, SEM, EPMA, FT-IR, UV-DRS, and TEM). Photocatalytic activity was performed for the degradation of rhodamine 6G under visible light. The results showed that CoTiO3-TiO2 composite photocatalysts were successfully synthesized. The average sizes of the diameters of the composite nanofibers were found to be 300 to 400 nm. The UV–Vis diffuse reflectance spectra of the CoTiO3-TiO2 composite showed an absorption wavelength, in the visible light region, having a band gap energy value of 2.21 eV. The CoTiO3-TiO2 composite showed higher photocatalytic efficiency than that of pristine TiO2; which can be attributed to the heterojunctional interaction between CoTiO3 and TiO2.

The Preparation of Platinum Nanoparticles on Titanium Using Chemical Reductive Growth Procedures

2012 ◽  
Vol 490-495 ◽  
pp. 3811-3815
Author(s):  
Li Guo ◽  
Jian Qiang Hu ◽  
Hu Zhang ◽  
Shi Zhao Yang
Keyword(s):  
Ascorbic Acid ◽  
Electron Microscope ◽  
Platinum Nanoparticles ◽  
Pt Nanoparticles ◽  
Resolution Electron ◽  
One Step ◽  
New Type ◽  
High Resolution Electron Microscope ◽  
The One ◽  
Fcc Structure

The synthesis of platinum nanoparticles by reduction of H2PtCl6 with ascorbic acid has been studied. By high-resolution electron microscope and XRD analyses, the resultant nanoparticles have been found to be pure platinum of fcc structure. Their sizes were observed to increase with the increases chemical reductive with 24h. Then, platinum nanoparticles directly attached to Ti plates(Pt nanoparticles/Ti) were successfully fabricated. In this method, platinum nanoparticles could be grown on the Ti surface via the one-step immersion into the growth solution containing PtCl62- and ascorbic acid. The attached and grown platinum nanoparticles were spherical having an agglomerated nanostructure composed of small nanoclusters. The present Pt nanoparticles/Ti may be promising for a new type of electrode material.

scholarly journals One Step Synthesis of Tetragonal-CuBi2O4/Amorphous-BiFeO3 Heterojunction with Improved Charge Separation and Enhanced Photocatalytic Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1514
Author(s):  
Fang Cai ◽  
Ting Zhang ◽  
Qiong Liu ◽  
Pengran Guo ◽  
Yongqian Lei ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Solvothermal Method ◽  
Removal Rate ◽  
Cost Effective ◽  
Mild Conditions ◽  
Methylene Orange ◽  
Post Annealing ◽  
One Step ◽  
The One

Tetragonal CuBi2O4/amorphous BiFeO3 (T-CBO/A-BFO) composites are prepared via a one-step solvothermal method at mild conditions. The T-CBO/A-BFO composites show expanded visible light absorption, suppressed charge recombination, and consequently improved photocatalytic activity than T-CBO or A-BFO alone. The T-CBO/A-BFO with an optimal T-CBO to A-BFO ratio of 1:1 demonstrates the lowest photoluminescence signal and highest photocatalytic activity. It shows a removal rate of 78.3% for the photodegradation of methylene orange under visible light irradiation for 1 h. XPS test after the cycle test revealed the reduction of Bi3+ during the photocatalytic reaction. Moreover, the as prepared T-CBO/A-BFO show fundamentally higher photocatalytic activity than their calcinated counterparts. The one-step synthesis is completed within 30 min and does not require post annealing process, which may be easily applied for the fast and cost-effective preparation of photoactive metal oxide heterojunctions.

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