Preparation and Processing of Monodisperse Colloidal Silica-Cadmium sulfide nanocomposites

1994 ◽  
Vol 346 ◽  
Author(s):  
Song-Yuan Chang ◽  
Lei Liu ◽  
Sanford A. Asher
Keyword(s):  
Cadmium Sulfide ◽  
Surface Area ◽  
Colloidal Silica ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Medium ◽  
Silica Particles ◽  
Linear Optics ◽  
Silica Colloids ◽  
Monodisperse Colloidal Silica

ABSTRACTA novel synthetic methodology has been developed for preparing monodisperse colloidal silica-cadmium sulfide nanocomposite spheres in the 50 – 300 nm size regime. This methodology uses water-in-oil microemulsions as the reaction medium. Monosize silica colloids are first produced by the controlled hydrolysis of tetraethyl orthosilicate in the micro water droplets of the microemulsion. Cadmium sulfide quantum dots are incorporated into the silica colloids during synthesis by the introductions of Cd2+ and S2- microemulsions. Various morphologies of the nanocomposite are fabricated by controlling the heterogeneous coagulation of CdS and SiO2. Unique high surface area silica particles can be prepared when nitric acid etches out the CdS and leaves behind topologically defined voids. The CdS nanocomposites are new materials useful for non-linear optics, while the high surface area silica particles should have novel applications in areas such as catalysis.

Metal nanoparticles: ligand free approach towards coupling reactions

2021 ◽  
Vol 01 ◽  
Author(s):  
Sharwari K. Mengane ◽  
Ronghui Wu ◽  
Liyun Ma ◽  
Chhaya S. Panse ◽  
Shailesh N. Vajekar ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Metal Nanoparticles ◽  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Medium ◽  
Coupling Reactions ◽  
Research Activities ◽  
Ligand Free

: Catalysis is the multidisciplinary field involving many areas of chemistry, notably in organometallic chemistry and materials science. It has great applications in synthesis of many industrially applicable compounds such as fuels and fine chemicals. The activity and selectivity are a key issue in catalysis that generally allied to high surface area. The current research activities mainly deal with the homogeneous and heterogeneous catalysis. Homogeneous and heterogeneous catalysis have certain drawbacks which restricts their application to great extent but have their own advantages. Hence, it has a predominant concern of current research to find out an alternate to overcome their drawbacks. Therefore, it is highly desirable to find a catalytic protocol that offers high selectivity and excellent product yield with quick and easy recovery. Along with their various applications as alternatives to conventional bulk materials nanomaterial have established its great role in different industrial and scientific applications. Nanocatalysis has emerged as new alternative to the conventional homogeneous and heterogeneous catalysis. The nanomaterials are responsible to enhance surface area of the catalyst, which ultimately increases the catalyst reactants contacts. In addition, it acts as robust material and has high surface area like heterogeneous catalysts. Insolubility of such nanomaterial in reaction medium makes them easily separable, hence, catalyst can be easily separate from the product. Hence, it has been proven that nanocatalysts behave like homogeneous as well as heterogeneous catalysts which work as a bridge between the conventional catalytic systems. Considering these merits; researchers has paid their attention towards applications of nanocatalyst in several organic reactions. This review article focused on the catalytic applications of metal nanoparticles (MNPs) such as Pd, Ag, Au, Cu, Pt in ligand free coupling reactions. In addition, it covers applications of bimetallic and multimetallic nanoparticles in ligand free coupling reactions.

scholarly journals The Geode Process I: Hollow Silica Microcapsules as a High Surface Area Substrate for Semiconductor Nanowire Growth

2019 ◽  
Author(s):  
Maritza Mujica ◽  
Gozde Tutuncuoglu ◽  
Amar Mohabir ◽  
Victor Breedveld ◽  
Sven Behrens ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Silica Particles ◽  
Nanowire Growth ◽  
Si Nanowires ◽  
Hollow Silica ◽  
Semiconductor Nanowire ◽  
Interior Surface ◽  
Emulsion Templating

<div><div><div><p>We introduce and demonstrate critical steps toward the Geode process for the bottom-up synthesis of semiconductor nanowires. Central to the process is the design and fabrication of an unconventional, high surface area substrate: the interior surface of hollow silica microcapsules, assembled from silica particles via emulsion templating, and featuring porous walls to enable efficient gas transport. The interior surface of these hollow silica microcapsules is decorated with gold nanoparticles that seed nanowire growth via the vapor-liquid-solid (VLS) mechanism. We demonstrate the production of the necessary microcapsules and show how microcapsule structure and stability upon drying is influenced by the type of silica particles and use of a particle cross-linking agent. Finally, we demonstrate the synthesis of Si nanowires in the microcapsule interior.</p></div></div></div>

High-surface area spherical micro-mesoporous silica particles

2016 ◽  
Vol 223 ◽  
pp. 225-229 ◽  
Author(s):  
Dmitry A. Kurdyukov ◽  
Daniil A. Eurov ◽  
Demid A. Kirilenko ◽  
Julia A. Kukushkina ◽  
Vasily V. Sokolov ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Silica Particles

scholarly journals The Geode Process I: Hollow Silica Microcapsules as a High Surface Area Substrate for Semiconductor Nanowire Growth

2019 ◽  
Author(s):  
Maritza Mujica ◽  
Gozde Tutuncuoglu ◽  
Amar Mohabir ◽  
Victor Breedveld ◽  
Sven Behrens ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Silica Particles ◽  
Nanowire Growth ◽  
Si Nanowires ◽  
Hollow Silica ◽  
Semiconductor Nanowire ◽  
Interior Surface ◽  
Emulsion Templating

<div><div><div><p>We introduce and demonstrate critical steps toward the Geode process for the bottom-up synthesis of semiconductor nanowires. Central to the process is the design and fabrication of an unconventional, high surface area substrate: the interior surface of hollow silica microcapsules, assembled from silica particles via emulsion templating, and featuring porous walls to enable efficient gas transport. The interior surface of these hollow silica microcapsules is decorated with gold nanoparticles that seed nanowire growth via the vapor-liquid-solid (VLS) mechanism. We demonstrate the production of the necessary microcapsules and show how microcapsule structure and stability upon drying is influenced by the type of silica particles and use of a particle cross-linking agent. Finally, we demonstrate the synthesis of Si nanowires in the microcapsule interior.</p></div></div></div>

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

High Surface Area NiCoP Nanostructure as Efficient Water Splitting Electrocatalyst for the Oxygen Evolution Reaction

2021 ◽  
pp. 111312
Author(s):  
Sisir Maity ◽  
Dheeraj Kumar Singh ◽  
Divya Bhutani ◽  
Suchitra Prasad ◽  
Umesh V. Waghmare ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Surface ◽  
High Surface Area
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