scholarly journals Accelerated room-temperature crystallization of ultrahigh-surface-area porous anatase titania by storing photogenerated electrons

2017 ◽  
Vol 53 (10) ◽  
pp. 1619-1621 ◽  
Author(s):  
Juan Su ◽  
Xiaoxin Zou ◽  
Binghan Li ◽  
Hui Chen ◽  
Xinhao Li ◽  
...  
Keyword(s):  
Reaction Time ◽  
Surface Area ◽  
Room Temperature ◽  
Surface Areas ◽  
Photogenerated Electrons ◽  
Anatase Titania ◽  
First Time ◽  
Temperature Crystallization

A technology for storing photogenerated electrons is for the first time applied for significantly accelerating the crystallization of amorphous TiO2 at room temperature (reducing the reaction time from 80 to 2 days). The resulting porous anatase titania exhibits ultrahigh surface areas up to 736 m2 g−1.

Mesoporous tantalum oxide photocatalysts for Schrauzer-type conversion of dinitrogen to ammonia

2005 ◽  
Vol 83 (4) ◽  
pp. 308-314 ◽  
Author(s):  
Chaoyang Yue ◽  
Michel L Trudeau ◽  
David Antonelli
Keyword(s):  
Surface Area ◽  
Tantalum Oxide ◽  
Catalytic Efficiency ◽  
Mesoporous Structure ◽  
Turnover Rates ◽  
Type Conversion ◽  
Electron Hole ◽  
Surface Areas ◽  
Before And After ◽  
First Time

Mesoporous tantalum oxide, Fe3+-doped mesoporous tantalum oxide, and bis(toluene) titanium reduced mesoporous tantalum oxide were used for the first time as Schrauzer-type photocatalysts for the conversion of dinitrogen to ammonia. The materials were characterized by XRD, TEM, XPS, and nitrogen absorption before and after catalytic runs. The results showed low to moderate activities depending on the composition. In contrast to previously studied Ti catalysts, Fe doping and heat pretreatment were not prerequisites for photocatalytic activity, but did improve the turnover rates by up to a factor of two. The optimal Fe loading for the tantalum oxides was found to be 1 wt% and the optimal heating condition at 300 °C for 3 h. Increased surface area and heat treatment were also found to improve activities. Contrary to our expectations, reduction of the mesostructure with bis(toluene) titanium had little effect on the catalytic activity. In spite of the dramatically higher surface areas of the mesoporous tantalum oxides as compared with bulk titanias used previously in this process, the overall catalytic activities were still less than those obtained in the Schrauzer system. This suggests that the increase in diffusion and surface area offered by the mesoporous structure is offset by the smaller crystalline domain sizes in the walls of the structure, leading to poor electron-hole separation and a reduction in catalytic efficiency. Key words: mesoporous, Schrauzer, ammonia, photocatalysis, tantalum oxide.

scholarly journals Preparation of Magnetically Driven Nickel Phosphide Nanowires and Their Electrochemical Properties

2021 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Hye-Won Kim ◽  
Heon-Cheol Shin
Keyword(s):  
Aspect Ratio ◽  
Surface Area ◽  
Phosphorus Content ◽  
Nickel Phosphide ◽  
Phase Synthesis ◽  
Reaction Surface ◽  
Surface Areas ◽  
Low Phosphorus ◽  
Degradation Degree ◽  
First Time

In this study, nickel phosphide nanowires with various structures and compositions were fabricated for the first time via magnetically-assisted liquid phase synthesis. The curvature and aspect ratio of the nanowires largely depended on the strength of the magnetic field applied during synthesis. Their phosphorus content together with the morphology were significantly modified according to the pH and reducing agent concentration. Nanowires with different structures and phosphorus contents were preliminarily tested for their capabilities to serve in general electrochemical applications. The degree of reaction (i.e., amount of reaction charge) increased with increases in the reaction area and phosphorus content of the nanowires. The rate characteristics of the reaction showed a peculiar increasing trend for a small reaction surface area and low phosphorus content. A change in the ohmic overpotential according to the nanowire curvature (aspect ratio) and porosity was suggested to be the reason for this unusual trend. Electrodes with high phosphorus contents or high reaction surface areas rapidly deteriorated during repetitive redox reactions. Based on the results for the degradation degree, the effect of the reaction surface area dominated that of the phosphorus content in the deterioration of the nickel phosphide nanowires.

scholarly journals Facile Synthesis of Nanostructured Anatase Titania with Controllable Morphology via Oxidation of TiC with Hydrogen Peroxide

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Yuduo Ren ◽  
WenTao Hu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Room Temperature ◽  
Acidic Solution ◽  
Amorphous Powder ◽  
Oxidation Time ◽  
Ambient Conditions ◽  
Facile Synthesis ◽  
Anatase Titania

Nanostructured anatase TiO2with controllable morphology has been fabricated via the oxidation of TiC with H2O2. At room temperature, the reaction of TiC with H2O2leads to dissolution of TiC into H2O2aqueous solution, producing an acidic solution. By drying the acidic solution at 80°C in air, an amorphous powder of polytitanic acid with oxalate ligands is obtained, and its morphology is found to rely on the reaction time. By annealing the amorphous acidic powder atT> 350°C, the nanostructured anatase TiO2with controllable morphology is generated. Depending on the oxidation time, the morphology can be fabricated as sponge-like shape, flower-like shape, spongy balls, and so forth. The nanostructured anatase TiO2is stable under the heating treatments until 900°C, and its morphology can be tuned to the nanocrystalline grains. In addition to the annealing way, rice-shaped anatase nanocrystals can be directly formed by aging the acidic solution under ambient conditions.

Au quantum dots engineered room temperature crystallization and magnetic anisotropy in CoFe2O4 thin films

2019 ◽  
Vol 4 (2) ◽  
pp. 434-444 ◽  
Author(s):  
Sagar E. Shirsath ◽  
Xiaoxi Liu ◽  
M. H. N. Assadi ◽  
Adnan Younis ◽  
Yukiko Yasukawa ◽  
...  
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Magnetic Anisotropy ◽  
Crystallization Kinetics ◽  
Room Temperature ◽  
Amorphous Substrates ◽  
First Time ◽  
Temperature Time ◽  
Temperature Crystallization

For the first time, this work presents a novel room temperature time-effective concept to manipulate the crystallization kinetics and magnetic responses of thin films grown on amorphous substrates.

Copper-Catalyzed Highly Efficient Esterification of Aldehydes with N-Hydroxyphthalimide via Cross-Dehydrogenative Coupling in Water at Room Temperature

Synlett ◽  
2017 ◽  
Vol 28 (11) ◽  
pp. 1321-1326 ◽  
Author(s):  
Can Jin ◽  
Weike Su ◽  
Zhicheng Guo ◽  
Xinpeng Jiang ◽  
Jiadi Zhou ◽  
...  
Keyword(s):  
Reaction Time ◽  
Efficient Method ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Short Reaction Time ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Dehydrogenative Coupling ◽  
First Time

A copper-catalyzed cross-dehydrogenative coupling reaction between N-hydroxyphthalimide and aldehydes using PhI(OAc)2 as an oxidant is described. It is reported for the first time to synthesize NHPI esters in water, providing the corresponding NHPI esters in moderate to good yields. This facile and efficient method is eco-friendly and possesses the advantages of mild conditions, short reaction time, and broad substrate scope.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

Room-temperature synthesis, growth mechanisms and opto-electronic properties of organic–inorganic halide perovskite CH3NH3PbX3 (X = I, Br, and Cl) single crystals

CrystEngComm ◽  
2021 ◽  
Author(s):  
Maryam Bari ◽  
Hua Wu ◽  
Alexei A. Bokov ◽  
Rana Faryad Ali ◽  
Hamel N. Tailor ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Single Crystals ◽  
Room Temperature ◽  
Solubility Curve ◽  
Inverse Temperature ◽  
Growth Mechanisms ◽  
Temperature Synthesis ◽  
Room Temperature Synthesis ◽  
Halide Perovskite ◽  
Temperature Crystallization

Growth of MAPbX3 (X = I, Br, and Cl) single crystals by room temperature crystallization (RTC) method, and the crystallization pathway illustrated by the solubility curve of MAPbCl3 in DMSO, compared with inverse temperature crystallization (ITC) method.

Room-temperature white and color-tunable afterglow by manipulating multi-mode triplet emissions

2021 ◽  
Vol 9 (9) ◽  
pp. 3257-3263
Author(s):  
Jianwei Liu ◽  
Zhimin Ma ◽  
Zewei Li ◽  
Yan Liu ◽  
Xiaohua Fu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Component ◽  
Color Tunable ◽  
First Time ◽  
Multi Mode

Two isomers pDCzPyCN and oDCzPyCN are designed and synthesized. Amazingly, oDCzPyCN manifest white afterglow at room temperature. This is the first time that single-component white afterglow has finally been realized.

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