查看完整版本: 今日纳米(Nano Today)2007V2N4:金纳米粒子催化专题

今日纳米(Nano Today)2007V2N4:金纳米粒子催化专题

[align=center][size=5][b]今日纳米(Nano Today)2007V2N4:金纳米粒子催化专题[/b][/size]
[/align]
[img]http://www.nanotoday.com/website%20images%202007/august/august_OFC.jpg[/img]
[b][纳米科技世界快讯】这期杂志主要介绍最近金纳米粒子催化的进展和总结。以三篇小的综述给出，应该比较全面的反映里纳米粒子Au的催化研究的最新进展。我是外行，请读者自己判断！[/b]

[quote]
[b][i]Nanotoday[/i][/b], Volume 2, Issue 4, August 2007, Pages 14-18;
[b]Review[/b]
[img]http://www.nanotoday.com/website%20images%202007/august/august_review_01.jpg[/img]
[size=4][b]Catalytic activity of Au nanoparticles[/b][/size]

Britt Hvolbæka, Ton V.W. Janssensb, Bjerne S. Clausenb, Hanne Falsigc, Claus H. Christensenc and Jens K. Nørskova, E-mail The Corresponding Author
aCenter for Atomic-scale Materials Design, Department of Physics, NanoDTU, Technical University of Denmark, DK-2800 Lyngby, Denmark
bHaldor Topsøe A/S, Nymøllevej 55, DK-2800 Lyngby, Denmark
cCenter for Sustainable and Green chemistry, Department of Chemistry, NanoDTU, Technical University of Denmark, DK-2800 Lyngby, Denmark

Abstract
Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional

Catalysts are widely used in the large-scale manufacture of chemicals and in the production of fine chemicals and pharmaceuticals. Fuel processing is a good example: the gasoline that we use in our cars requires at least ten different catalysts during its transformation from crude oil. Environmental technologies also rely heavily on catalysts; the best known example being the catalytic converter in the exhaust of every car. It is estimated that more than 20% of the gross national product (GNP) of industrial countries relies in one way or another on catalysis
[img]http://img296.imageshack.us/img296/2536/0wchpdglbvzbzskww2fd9f0wo3.jpg[/img]
[img]http://img300.imageshack.us/img300/320/0wchpdglbvzwzskzs2fe8e3bp1.jpg[/img]

[/quote]

[quote]
[b]Review[/b]
[img]http://www.nanotoday.com/website%20images%202007/august/august_review_02.jpg[/img]
[b][size=4]Mind the gap! Spectroscopy of catalytically active phases

Volume 2, Issue 4, August 2007, Pages 20-29

[/size][/b]Günther Rupprechtera, E-mail The Corresponding Author and Christian Weilacha
aInstitute of Materials Chemistry, Vienna University of Technology, Veterinärplatz 1, A-1210 Vienna, Austria

Abstract
Recent advances in model catalysis and in spectroscopic methods that can operate at ambient pressure now enable us to investigate a catalyst in its active state, i.e. while it is functioning. Laser spectroscopy, polarization-modulated infrared (IR) spectroscopy, and high pressure photoelectron spectroscopy allow monitoring of the transformation of catalysts from the ‘as-prepared’ to the ‘active-state’, which may involve pronounced changes in catalyst structure and composition. The ultimate goal is the characterization and control of the active sites. A number of case studies are presented for Pd-based catalysts, including both single crystal and nanoparticle model catalysts, which illustrate the complex and dynamic behavior of catalytically active surfaces, with emphasis on Pd hydrides, Pd−C phases, Pd surface oxides, and bimetallic surfaces. There is clearly a need to ‘mind the gap’ between investigations under ultrahigh vacuum (UHV) and those at ambient pressure, as well as to account for the inherent differences between supported nanoparticles and extended single crystal surfaces.

The characterization and, particularly, the control of the active sites of a catalyst is the ‘holy grail’ of heterogeneous catalysis research. A molecular-level understanding of how a catalyst works may eventually allow a process to run with 100% selectivity, avoiding undesired or even harmful side products, which is a prerequisite for green chemistry. However, catalysis is a complex, dynamic nanoscale process that generally seems to be rather reluctant to reveal its exact mechanism. Modern instruments and dedicated research strategies are required for a fundamental understanding of catalysis.

[img]http://img228.imageshack.us/img228/3621/0wchpdglbvzzzskwb30228eom6.jpg[/img]
[i]Schematic illustration of the most frequently used monometallic and bimetallic model catalysts: UHV-grown nanoparticles supported by thin oxide films (upper row) and noble metal and alloy single crystal surfaces (lower row).[/i]
[img]http://img143.imageshack.us/img143/7348/0wchpdglbvzbzskww30305eto1.jpg[/img]
[i] Illustration of high pressure spectroscopic techniques that are capable of monitoring adsorbed and reacting molecules under realistic pressure conditions (millibar to >1 bar range). Differing results between studies under UHV and ambient pressure indicate the importance to ‘mind the gap’ between low pressure and high pressure studies.[/i]


[/quote]

[quote]
[b]Applications[/b]
[img]http://www.nanotoday.com/website%20images%202007/august/august_review_03.jpg[/img][size=4][b]
Using gold nanoparticles for catalysis [/b][/size]

Volume 2, Issue 4, August 2007, Pages 40-43

David T. Thompsona, E-mail The Corresponding Author
aConsultant to Project AuTEK, Mintek, South Africa and World Gold Council, London, UK

Abstract
Nanoparticulate Au catalysts are active under mild conditions, even at ambient temperature or less, and this makes them unique. They will therefore be effective in reducing running costs of chemical plants and could increase the selectivity of the reactions involved where applicable. In pollution control applications, such as air cleaning, low light-off autocatalysts, and purification of hydrogen streams used for fuel cells, they have the characteristics to become the catalysts of choice, especially now that their durability and resistance to poisons is being shown to be better than had been anticipated. Use of mixed precious metal catalysts can produce even higher activities than the use of Au alone.

Au is readily prepared on the nanoscale and is already being used in this form in a range of applications, including the biomedical monitoring of constituents in body fluids and in decorative inks, cosmetics, and lubricants1. Another aspect of nanoparticulate Au that is particularly exciting is its use in catalysis, and developments in this new technology are considered here.
[img]http://img141.imageshack.us/img141/9491/0wchpdglbvzbzskzk307120nx3.jpg[/img]
Comparison of CO tolerance results (1000 ppm CO, 0.5 A cm−2, 1.5 times stoichiometric hydrogen flow rate, SV over 3 wt.% Au/TiO2 catalyst = 250 000 ml gcat−1 h−1, Au-based catalyst chamber at 25°C, fuel cell at 80°C, 30 psi25). (Reproduced by permission of Mintek, the copyright holder.)
[/quote]

:downloads :box
**** Hidden Message *****

好文章，多谢楼主分享

曾经关注过，！！！！

很好的文章，多谢分享！

多谢分享:victory: :victory:

谢谢分享！！！！！！！！

今日纳米(Nano Today)2007V2N4:金纳米粒子催化专题
经典

好文章，多谢楼主分享

:lol ,good,:handshake

Thanks a lot for your sharing!

好书多多，全力支持!!!!!!!!!!!!!!!!!!!!!!!!!!!!

好文章......

感动啊，实在是经典的东西

:lol 谢谢分享:lol
:hand

:victory: :victory: :victory: :victory:

回复 1# 的帖子

好文章，多谢楼主分享

Thanks a lot for your sharing!

thank you very much!

多谢分享！！！！！！！！！！！

多谢分享，支持！！！！！