Influence of the impregnation order of molybdenum and cobalt in carbon supported catalysts for hydrodeoxygenation reactions

1998 ◽  
pp. 505-515 ◽  
Author(s):  
M. Ferrari ◽  
C. Lahousse ◽  
A. Centeno ◽  
R. Maggi ◽  
P. Grange ◽  
...  
Keyword(s):  
Supported Catalysts

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

1993 ◽  
Vol 51 ◽  
pp. 1058-1059
Author(s):  
J. Liu ◽  
M. Pan ◽  
G. E. Spinnler
Keyword(s):  
Supported Catalysts ◽  
Imaging Techniques ◽  
Nano Particles ◽  
Metal Particles ◽  
Shape Structure ◽  
Dynamical Simulations ◽  
Small Metal Particles ◽  
Extract Information

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

Elemental Distribution in Pt-Re:Al2O3 Naphtha Reforming Catalysts

1980 ◽  
Vol 38 ◽  
pp. 200-201
Author(s):  
R. L. Freed ◽  
M. J. Kelley
Keyword(s):  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Materials Characterization ◽  
Metal Catalyst ◽  
Elemental Distribution ◽  
Exact Nature ◽  
Naphtha Reforming ◽  
Reforming Catalysts ◽  
Commercial Introduction

The commercial introduction of Pt-Re supported catalysts to replace Pt alone on Al2O3 has brought improvements to naphtha reforming. The bimetallic catalyst can be operated continuously under conditions which lead to deactivation of the single metal catalyst by coke formation. Much disagreement still exists as to the exact nature of the bimetallic catalyst at a microscopic level and how it functions in the process so successfully. The overall purpose of this study was to develop the materials characterization tools necessary to study supported catalysts. Specifically with the Pt-Re:Al2O3 catalyst, we sought to elucidate the elemental distribution on the catalyst.

METAL SUPPORTED CATALYSTS FOR NOX DECOMPOSITION

2006 ◽  
Vol 5 (1) ◽  
pp. 29-35
Author(s):  
Nechita Mircea Teodor ◽  
Apostolescu Nicolae ◽  
Apostolescu Gabriela ◽  
Adrian Cailean
Keyword(s):  
Supported Catalysts

An Overview of Metal-organic Frameworks-based Acid/Base Catalysts for Biofuel Synthesis

2020 ◽  
Vol 24 (16) ◽  
pp. 1876-1891
Author(s):  
Qiuyun Zhang ◽  
Yutao Zhang ◽  
Jingsong Cheng ◽  
Hu Li ◽  
Peihua Ma
Keyword(s):  
Alternative Fuels ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Flexible Structures ◽  
Biodiesel Production ◽  
Biodiesel Synthesis ◽  
Metal Organic ◽  
Organic Framework

Biofuel synthesis is of great significance for producing alternative fuels. Among the developed catalytic materials, the metal-organic framework-based hybrids used as acidic, basic, or supported catalysts play major roles in the biodiesel production. This paper presents a timely and comprehensive review of recent developments on the design and preparation of metal-organic frameworks-based catalysts used for biodiesel synthesis from various oil feedstocks, including MILs-based catalysts, ZIFs-based catalysts, UiO-based catalysts, Cu-BTC-based catalysts, and MOFs-derived porous catalysts. Due to their unique and flexible structures, excellent thermal and hydrothermal stability, and tunable host-guest interactions, as compared with other heterogeneous catalysts, metal-organic framework-based catalysts have good opportunities for application in the production of biodiesel at industrial scale.

Characterization of the surface of hydrodesulphurization catalysts by adsorption of hydrocarbons

1984 ◽  
Vol 49 (2) ◽  
pp. 410-420
Author(s):  
Eva Hillerová ◽  
Miroslav Zdražil
Keyword(s):  
Hydrogen Sulphide ◽  
Chromatographic Method ◽  
Supported Catalysts ◽  
Alumina Surface ◽  
Reversible Adsorption ◽  
The Difference

Reversible adsorption of heptane and benzene on model and industrial hydrodesulphurization molybdena catalysts has been studied by elution chromatographic method at 150 °C. An increase in the adsorption of heptane on sulphidation of adsorbents was small for Al2O3 and great for MoO3. Supported catalysts behaved as mixture of Al2O3 and MoO3.The portion of surface which can be transformed by sulphidation into MoS2 ranged from 0 to 65% for individual commercial catalysts, as determined from the change in heptane adsorption after sulphidation of a given sample. The polarity of catalysts, including their acidity, was estimated from the difference between adsorption of benzene and heptane. The polarity of model and industrial catalysts in oxidic form was similar to that of alumina in most cases. The decrease in the polarity after sulphidation of the adsorbents was small for Al2O3 and great for MoO3. The decrease in polarity resulting from sulphidation of supported catalysts was relatively small, since the reaction of MoO3 monolayer with hydrogen sulphide leads to partial reformation of the alumina surface. The acidity of supported sulphided hydrodesulphurization catalysts has been shown by this method to be comparable with the acidity of the support itself.

Hydrodesulphurization of thiophene over zirconia and alumina supported Co-Mo catalysts

1989 ◽  
Vol 54 (8) ◽  
pp. 2064-2068 ◽  
Author(s):  
Jiří Sedláček ◽  
Zdeněk Vít
Keyword(s):  
Total Pressure ◽  
Supported Catalysts ◽  
Atomic Concentration ◽  
Commercial Sample ◽  
Sulphur Oxidation ◽  
Como Catalysts ◽  
Zirconia Support ◽  
Como Catalyst ◽  
Concentration Ratios

The zirconia supported CoMo catalysts and the commercial sample CoMo/Al2O3 were characterized by XPS measurements and by testing of activity in the HDS of thiophene at 280 °C and 1 MPa of total pressure. The XPS measurements revealed the better reducibility of molybdenum, higher sulphidability of cobalt and the absence of surface sulphur oxidation in the presence of zirconia support. The surface atomic concentration ratios S/Mo were 1.2 and 2.2 for zirconia and alumina supported catalysts, respectively. The activity of the zirconia supported CoMo catalyst normalized to the overal amounts of active metals was lower than that of the commercial CoMo/Al2O3 catalyst.

scholarly journals Electrodeposition of palladium-dotted nickel nanowire networks as a robust self-supported methanol electrooxidation catalyst

2021 ◽  
Author(s):  
Tim Boettcher ◽  
Sasho Stojkovikj ◽  
Prashant Khadke ◽  
Ulrike Kunz ◽  
Matthew T. Mayer ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
High Mass ◽  
Potential Cycling ◽  
Free Standing ◽  
Term Stability ◽  
Long Term Stability ◽  
Mass Activity ◽  
Nickel Nanowire ◽  
Nanowire Networks

Abstract Mass activity and long-term stability are two major issues in current fuel cell catalyst designs. While supported catalysts normally suffer from poor long-term stability but show high mass activity, unsupported catalysts tend to perform better in the first point while showing deficits in the latter one. In this study, a facile synthesis route towards self-supported metallic electrocatalyst nanoarchitectures with both aspects in mind is outlined. This procedure consists of a palladium seeding step of ion track-etched polymer templates followed by a nickel electrodeposition and template dissolution. With this strategy, free-standing nickel nanowire networks which contain palladium nanoparticles only in their outer surface are obtained. These networks are tested in anodic half-cell measurements for demonstrating their capability of oxidising methanol in alkaline electrolytes. The results from the electrochemical experiments show that this new catalyst is more tolerant towards high methanol concentrations (up to $${5}\,\hbox{mol}\,\hbox{L}^{-1}$$ 5 mol L - 1 ) than a commercial carbon supported palladium nanoparticle catalyst and provides a much better long-term stability during potential cycling. Graphical Abstract

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