The Effect of Al2O3 Addition on Catalytic Activities of NiSO4/Al2O3-ZrO2 for Acid Catalysis

2005 ◽  
Vol 38 (10) ◽  
pp. 791-800 ◽  
Author(s):  
Jong Rack Sohn ◽  
Jun Seob Lim
Keyword(s):  
Acid Catalysis ◽  
Catalytic Activities ◽  
Al2o3 Addition

scholarly journals Advances in Nanostructured Metal-Encapsulated Porous Organic-Polymer Composites for Catalyzed Organic Chemical Synthesis

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 492 ◽  
Author(s):  
Wilhemina Sebati ◽  
Suprakas Ray
Keyword(s):  
Binding Sites ◽  
Heterogeneous Catalysts ◽  
Acid Catalysis ◽  
High Surface ◽  
Organic Polymer ◽  
Organic Chemical ◽  
Characterization Methods ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Nanostructured Metal

Porous organic polymers (POPs) are of growing research interest owing to their high surface areas, stabilities, controllable chemical configurations, and tunable pore volumes. The molecular nanoarchitecture of POP provides metal or metal oxide binding sites, which is promising for the development of advanced heterogeneous catalysts. This article highlights the development of numerous kinds of POPs and key achievements to date, including their functionalization and incorporation of nanoparticles into their framework structures, characterization methods that are predominantly in use for POP-based materials, and their applications as catalysts in several reactions. Scientists today are capable of preparing POP-based materials that show good selectivity, activity, durability, and recoverability, which can help overcome many of the current environmental and industrial problems. These POP-based materials exhibit enhanced catalytic activities for diverse reactions, including coupling, hydrogenation, and acid catalysis.

Isostructural mesoporous ionic crystals as a tunable platform for acid catalysis

2020 ◽  
Vol 49 (30) ◽  
pp. 10328-10333
Author(s):  
Yuto Shimoyama ◽  
Zhewei Weng ◽  
Naoki Ogiwara ◽  
Takashi Kitao ◽  
Yuji Kikukawa ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Ionic Crystals ◽  
Catalytic Activities

The catalytic activities are highly dependent on the components of meso-PICS.

Heteropoly Compounds: Efficient Superacid Catalysts

1994 ◽  
Vol 368 ◽  
Author(s):  
Makoto Misono ◽  
Toshio Okuhara
Keyword(s):  
Acid Catalysis ◽  
Tertiary Structure ◽  
High Surface ◽  
Surface Concentration ◽  
Acid Sites ◽  
Heteropoly Compounds ◽  
Catalytic Activities ◽  
High Surface Concentration ◽  
Superacid Catalysts ◽  
Constituent Elements

ABSTRACTOur recent studies on the acidity and acid catalysis of heteropoly compounds are described, together with a brief introduction of the background. High catalytic activities were observed due to the combination of their superacidity, pseudoliquid behavior, acid-base bifunctionality and/or high surface concentration of proton. It was also shown how the acid strength and the number of acid sites as well as their tertiary structure were controlled by the constituent elements (heteroand addenda-atoms and counter cations), and how those properties were correlated with the catalytic activities

Catalytic Activities of Al2O3-promoted NiSO4/TiO2 for Acid Catalysis

2006 ◽  
Vol 108 (1-2) ◽  
pp. 71-78 ◽  
Author(s):  
Jong Rack Sohn ◽  
Jun Seob Lim
Keyword(s):  
Acid Catalysis ◽  
Catalytic Activities

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Metal-Assisted Plasma Etching of Silicon: A Liquid-Free Alternative to MACE

2018 ◽  
Author(s):  
Julia Sun ◽  
Benjamin Almquist
Keyword(s):  
Liquid Phase ◽  
Plasma Etching ◽  
Chemical Etching ◽  
Gold Films ◽  
Metallic Films ◽  
Au Catalyst ◽  
Feed Concentration ◽  
Catalytic Activities ◽  
Metal Assisted Chemical Etching ◽  
Complex Nanostructures

For decades, fabrication of semiconductor devices has utilized well-established etching techniques to create complex nanostructures in silicon. Of these, two of the most common are reactive ion etching in the gaseous phase and metal-assisted chemical etching (MACE) in the liquid phase. Though these two methods are highly established and characterized, there is a surprising scarcity of reports exploring the ability of metallic films to catalytically enhance the etching of silicon in dry plasmas via a MACE-like mechanism. Here, we discuss a <u>m</u>etal-<u>a</u>ssisted <u>p</u>lasma <u>e</u>tch (MAPE) performed using patterned gold films to catalyze the etching of silicon in an SF<sub>6</sub>/O<sub>2</sub> mixed plasma, selectively increasing the rate of etching by over 1000%. The degree of enhancement as a function of Au catalyst configuration and relative oxygen feed concentration is characterized, along with the catalytic activities of other common MACE metals including Ag, Pt, and Cu. Finally, methods of controlling the etch process are briefly explored to demonstrate the potential for use as a liquid-free fabrication strategy.

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