Structural modification towards metastable states and catalytic activity of an amorphous Ni–B alloy

1984 ◽  
pp. 868-869 ◽  
Author(s):  
Hiromi Yamashita ◽  
Takuzo Funabiki ◽  
Satohiro Yoshida
Keyword(s):  
Catalytic Activity ◽  
Structural Modification ◽  
Metastable States

scholarly journals Structural modification of perovskites by tailored exsolution for enhanced catalytic activity

2019 ◽  
Vol 75 (a2) ◽  
pp. e322-e322
Author(s):  
Raffael Rameshan ◽  
Christoph Rameshan ◽  
Thomas Ruh ◽  
Andreas Nenning ◽  
Alexander Opitz
Keyword(s):  
Catalytic Activity ◽  
Structural Modification

scholarly journals Mechanical Alloying: an Alternative Method to Produce NiMoW HDS Catalysts

2021 ◽  
Vol 65 (1) ◽  
Author(s):  
R. Huirache-Acuña ◽  
G. Alonso-Núñez ◽  
R. Martínez-Sánchez
Keyword(s):  
Catalytic Activity ◽  
Mechanical Alloying ◽  
Specific Surface ◽  
Structural Modification ◽  
Chemical Extraction ◽  
Quaternary Alloys ◽  
Alkaline Leaching ◽  
Hds Catalysts ◽  
Para Determinar ◽  
The Impact

Abstract. In this work, quaternary alloys of Ni-Mo-W-Al were prepared by mechanical alloying. In addition, a process of chemical extraction by alkaline leaching was applied to remove aluminum in order to increase the specific surface area (SSA) and to generate porous materials, which were tested in the dibenzothiophene (DBT) hydrodesulfurization (HDS) reaction to determine their catalytic activity and selectivity. This study reveals the impact of the surface and structural modification of quaternary alloys on the catalyst performance and serves as well, as guidance for the design of novel HDS catalysts.   Resumen. En este trabajo, se prepararon mediante aleado mecánico aleaciones cuaternarias de Ni-Mo-W-Al. Adicionalmente, un proceso de extracción química mediante lixiviación alcalina se aplicó para eliminar aluminio con la finalidad de incrementar el área específica y generar materiales porosos, los cuales fueron activados y evaluados en la reacción de hidrodesulfuración (HDS) de dibenzotiofeno (DBT) para determinar su actividad catalítica y selectividad. Este estudio revela el impacto de la modificación estructural y superficial de las aleaciones cuaternarias sobre el comportamiento de los catalizadores y sirve como guía, además, para el diseño de nuevos catalizadores para HDS.

Structural modification of zirconia and its influence on the catalytic activity

1995 ◽  
Vol 30 (24) ◽  
pp. 6355-6358 ◽  
Author(s):  
S. Narayanan ◽  
M. S. Krishnan ◽  
V. Vishwanathan
Keyword(s):  
Catalytic Activity ◽  
Structural Modification

A mini-review on the synthesis and structural modification of g-C3N4-based materials, and their applications in solar energy conversion and environmental remediation

2019 ◽  
Vol 3 (11) ◽  
pp. 2907-2925 ◽  
Author(s):  
Mohammed Ismael ◽  
Ying Wu
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Water Splitting ◽  
Organic Pollutants ◽  
Visible Light Irradiation ◽  
Conjugated Polymer ◽  
Environmental Remediation ◽  
Carbon Nitride ◽  
Structural Modification ◽  
Metal Free

Recently, graphitic carbon nitride (g-C3N4) as a metal-free conjugated polymer has emerged as a photocatalyst showing catalytic activity for water splitting, CO2 photoreduction and degradation of organic pollutants under visible light irradiation.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

Cristal-growth dynamics of n-doped gaAs

1992 ◽  
Vol 50 (2) ◽  
pp. 1544-1545
Author(s):  
Pham V. Huong ◽  
Stéphanie Bouchet ◽  
Jean-Claude Launay
Keyword(s):  
Crystal Growth ◽  
Spatial Resolution ◽  
Epitaxial Layer ◽  
Outer Surface ◽  
Gaas Substrate ◽  
Structural Modification ◽  
Growth Dynamics ◽  
Argon Laser ◽  
High Anisotropy ◽  
Crystal Gaas

Microstructure of epitaxial layers of doped GaAs and its crystal growth dynamics on single crystal GaAs substrate were studied by Raman microspectroscopy with a Dilor OMARS instrument equipped with a 1024 photodiode multichannel detector and a ion-argon laser Spectra-Physics emitting at 514.5 nm.The spatial resolution of this technique, less than 1 μm2, allows the recording of Raman spectra at several spots in function of thickness, from the substrate to the outer deposit, including areas around the interface (Fig.l).The high anisotropy of the LO and TO Raman bands is indicative of the orientation of the epitaxial layer as well as of the structural modification in the deposit and in the substrate at the interface.With Sn doped, the epitaxial layer also presents plasmon in Raman scattering. This fact is already very well known, but we additionally observed that its frequency increases with the thickness of the deposit. For a sample with electron density 1020 cm-3, the plasmon L+ appears at 930 and 790 cm-1 near the outer surface.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

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