Author Archive
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May 14th, 2009
Beefing-up the Activity and Durability of Gold-Catalysed Low-Temperature Water-Gas Shift Reaction (WGSR)
In a paper entitled ‘Investigation on gold dispersion of Au/ZrO2 catalysts and activity in the low-temperature WGS reaction’, F Zane, V Trevisan, F Pinna, M Signoretto and F Menegazzo, of the Dipartimento di Chimica, Universita Ca Foscari, Dorsoduro, and Consorzio INSTM-UdR Venezia, Italy, Appl Catal B:Env, 2009, 89(1-2), 303 – 308, sulfated zirconia has been shown to have higher activities than zirconia itself when used as a support for gold for the low-temperature WGS reaction (see also patent by A Kuperman and ME Moir of Chevron, California, USA, WO Patent 2005/005032, which claims unusually good durability for such catalysts):
CO + H2O -> H2 + CO2
The sulfated catalysts promote better dispersion of the gold nanoparticles on the support rather than act as promoters for the gold active phase. Results include demonstration of a good relationship between catalytic activity and chemisorption data.
This work will have important commercial implications in providing quantity hydrogen supplies in the future.
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April 17th, 2009
Reviews on Bioinorganic and Biomedical Chemistry of Gold
The June 2009 issue of Coordination Chemistry Reviews, to be published by Elsevier will contain a number of articles relevant to new biomedical applications for gold. The eleven papers include ‘Gold nanoparticle probes’ by Zhenzin Wang and Lina Ma, ‘Luminescence properties of phosphinegold(I) halides and thiolates by Edward Tietink and Jun-Gill Kang, ‘The tumour proteasome as a novel target for gold(III) complexes: implications for breast cancer therapy’ by Vesna Milacic and Q Ping Dou, and ‘Structures and properties of gold(I) complexes of interest in biochemical applications’ by John P Fackler Jr et al. In addition, there are three articles on use of gold compounds as anticancer drugs. This publication will assist in defining the significant number of biomedical applications now expected for nanoparticulate gold and gold compounds.
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April 16th, 2009
Gold Promoter for Methanol Synthesis Catalyst
One of the most important intermediates for large scale processing in the chemical industry is methanol. When 1, 2, and 3wt%Au/ZnO catalysts were prepared via a colloidal route and evaluated for methanol synthesis from syn gas, gold particles had a uniform size and there was very little particle growth at 573 K/ 40 bar. Measurements were made with CO/H2 and CO/H2/CO2 gas and all the samples exhibited higher catalytic activity in the absence of CO2. The presence of Au led to increased activity compared with using ZnO itself as a catalyst, and this was attributed to an increased number of exposed oxygen vacancies, probably located at the interface region between the support and the gold particles.
See: ‘Au/ZnO as catalyst for methanol synthesis: the role of oxygen vacancies’, J Strunk, K Kähler, X Xia, M Comotti, F Schüth, T Reinecke and M Muhler, Appl Catal A:Gen, 2009, 359(1-2), 121 – 128.
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March 25th, 2009
New 3M Patents on Gold Catalysts for Environmental and Chemical Applications
The team working on preparation of gold catalysts via physical vapour deposition (PVD) at 3M in the USA have had two new patents published, i.e. ‘Selective oxidation of carbon monoxide relative to hydrogen using catalytically active gold’ (WO Patent 2008/076137 A2) (PROX) and ‘Catalyst production process’ (WO Patent 2009/026035 A2). This PVD method for making gold catalysts means gold is deposited onto oxide supports in an oxidising atmosphere. They are chloride-free, and there is therefore no need for washing with water to remove unwanted chloride. Carbon can also be used as a support. These gold catalysts have characteristics useful for removing carbon monoxide from hydrogen for fuel cell feeds, and in respirators to protect users from carbon monoxide poisoning during escape from fires, etc. Other uses claimed are in vehicle and building protection, purification of exhaust gases from internal combustion engines, oxidation of carbonaceous soot in diesel exhaust streams and selective oxidation of organic compounds. The catalysts are active and durable.
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March 2nd, 2009
CatGold News in New Clothing!
CatGold News
has been published for a number of years by World Gold Council. It’s aim has been to highlight recent advances in gold catalysis – both science and applications.With the advent of this blog you will no longer need to wait for CatGold News to be published. Instead, there will be frequent new updates to highlight significant news on gold catalysis advances on these pages.
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March 2nd, 2009
GOLD 2009
New gold technology will be headlined at an International Conference in Heidelberg, Germany in July
Between three and four hundred leading gold scientists will be attending this exciting conference and there will be lots of opportunities for discussion.
There will also be many social events for for participants and their accompanying persons
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March 2nd, 2009
Gold nanoparticles may revolutionise safety of hydrogen peroxide production
The explosion of a lorry on the M25, London’s orbital motorway, in 2005 highlighted the danger of transporting hydrogen peroxide, one of the most widely used chemicals in modern industry. The discovery by scientists at Cardiff University in Wales that gold palladium nanoparticles can synthesise hydrogen peroxide directly may revolutionise it’s safe production.Scientists led by Prof Graham Hutchings, of Cardiff University, UK, have devised a method for making hydrogen peroxide directly from hydrogen and oxygen. This project was funded from EU AURICAT and World Gold Council’s GROW funding, and they have developed a simple, clean method for producing hydrogen peroxide, which is widely used as an antiseptic and disinfectant. The results could lead to the on-site production of hydrogen peroxide in smaller quantities and at weaker concentrations, thereby avoiding the risks associated with the transport and storage of large amounts of highly concentrated hydrogen peroxide.
The work was published in the journal Science on 20 February 2009 and indicates that pretreatment of the carbon support for the gold-palladium catalyst with nitric or acetic acid produces an active and durable catalyst which gives high yields of hydrogen peroxide and ‘switches off’ the subsequent decomposition reaction to water.
Producing this important substance currently entails an energy-intensive process, and the economics of this process mean it is made in larger quantities and at stronger concentrations than are needed in most applications. As a result, large amounts of the chemical must be stored and transported; this can be hazardous, as the explosion of a lorry carrying hydrogen peroxide on a UK motorway showed.
This new process could allow users of hydrogen peroxide on-site in the quantities they require.
David Thompson
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