Tag Archives: palladium

Graphene-gilded artifacts (or artefacts)

Caption: L: An artist rendering of graphene gilding on Tutankhamun’s middle coffin (original photograph copyright: Griffith Institute, University of Oxford). R: Microscope image of a graphene crystal is shown on the palladium leaf. Although graphene is only a single atom thick, it can be observed in the scanning electron microscope. Here, a small crystal of graphene is shown to observe its edges. The team produces leaves where the graphene fully cover the metal surface. Credit: Original photograph copyright: Griffith Institute, University of Oxford

As icons go, Tutankhamun’s middle coffin ranks highly and it’s a great image to use as an example of what might be accomplished with graphene gilding. From a Sept. 10, 2018 news item on Nanowerk,

Gilding is the process of coating intricate artifacts with precious metals. Ancient Egyptians and Chinese coated their sculptures with thin metal films using gilding—and these golden sculptures have resisted corrosion, wear, and environmental degradation for thousands of years. The middle and outer coffins of Tutankhamun, for instance, are gold leaf gilded, as are many other ancient treasures.

In a new study, Illinois’ Sameh Tawfick, from the Department of Mechanical Science & Engineering (MechSE) and the Beckman Institute, inspired by this ancient process, has added a single layer of carbon atoms, known as graphene, on top of metal leaves—doubling the protective quality of gilding against wear and tear.

A Sept. 10, 2018 University of Illinois news release (also on EurekAlert), which originated the news item, offers more details,

Metal leaves, or foils, offer many advantages as a scalable coating material, including their commercial availability in large rolls and their comparatively low price. By bonding a single layer of graphene to the leaves, Tawfick and his team demonstrated unexpected benefits, including enhanced mechanical resistance. Their work presents exciting opportunities for protective coating applications on large structures like buildings or ship hulls, metal surfaces of consumer electronics, and small precious artifacts or jewelry.

“Adding one more layer of graphene atoms onto the palladium made it twice as resistant to indents than the bare leaves alone,” said Tawfick. “It’s also very attractive from a cost perspective. The amount of graphene needed to cover the gilded structures of the Carbide & Carbon Building in Chicago, for example, would be the size of the head of a pin.”

Additionally, the team developed a new technology to grow high-quality graphene directly on the surface of 150 nanometer-thin palladium leaves—in just 30 seconds. Using a process called chemical vapor deposition, in which the metal leaf is processed in a 1,100°C furnace, the bare palladium leaf acts as a catalyst, allowing the gases to react quickly.

“Chemical vapor deposition of graphene requires a very high temperature, which could melt the leaves or cause them to bead up by a process called solid state dewetting,” said Kaihao Zhang, PhD candidate in MechSE and lead author of the study. “The process we developed deposits the graphene quickly enough to avoid high-temperature degradation, it’s scalable, and it produces graphene of very high quality.”

Here’s a link to and a citation for the paper,

Gilding with Graphene: Rapid Chemical Vapor Deposition Synthesis of Graphene on Thin Metal Leaves by Kaihao Zhang, Charalampos Androulidakis, Mingze Chen, Sameh Tawfick. Advanced Functional Materials DOI: https://doi.org/10.1002/adfm.201804068 First published: 06 September 2018

This paper is behind  a paywall.

Are copper nanoparticles good candidates for synthesizing medicine?

This research appears to be a collaboration between Russian and Indian scientists. From a December 5, 2017 news item on Nanowerk (Note: A link has been removed),

Chemists of Ural Federal University with colleagues from India proved the effectiveness of copper nanoparticles as a catalyst on the example of analysis of 48 organic synthesis reactions (Coordination Chemistry Reviews, “Copper nanoparticles as inexpensive and efficient catalyst: A valuable contribution in organic synthesis”).

One of the advantages of the catalyst is its insolubility in traditional organic solvents. This makes copper nanoparticles a valuable alternative to heavy metal catalysts, for example palladium, which is currently used for the synthesis of many pharmaceuticals and is toxic for cells.

“Copper nanoparticles are an ideal variant of a heterophasic catalyst, since they exist in a wide variety of geometric shapes and sizes, which directly affects the surface of effective mass transfer, so reactions in the presence of this catalyst are characterized by shorter reaction times, selectivity and better yields,” says co-author Grigory Zyryanov, Doctor of Chemistry, Associate Professor of the Department of Organic and Biomolecular Chemistry of UrFU.

A December 11, 2017 (there can be a gap between distributing a press release and posting it on the home website) Ural Federal University press release, which originated the news item, makes the case for copper nanoparticles as catalytic agents,

Copper nanoparticles are inexpensive since there are many simple ways to obtain them from cheap raw materials and these methods are constantly being modified. As a result, it is possible to receive a highly porous structure of catalyst based on copper nanoparticles with a pore size of several tens to several hundred nanometers. Due to the small particle size, the area of the catalytic surface is enormous. Moreover, due to the insolubility of copper nanoparticles, the reactions catalyzed by them go on the surface of the catalyst. After the reaction is completed, the copper nanoparticles that do not interact with the solvents are easily removed, which guarantees the absence of the catalyst admixture in the composition of the final product. These catalysts are already in demand for organic synthesis by the methods of “green chemistry”. Its main principles are simplicity, cheapness, safety of production, recyclability of the catalysts.

One of the promising areas of application of the copper nanoparticle catalyst is, first of all, the creation of medical products using cross-coupling reactions. In 2010, for work in the field of palladium catalyzed cross-coupling reactions, the Nobel Prize in Chemistry was awarded to scientists from Japan and the USA: Richard Heck, Ei-ichi Negishi and Akira Suzuki. Despite worldwide recognition, palladium catalyzed cross-coupling reactions are undesirable for the synthesis of most medications due to the toxicity of palladium for living cells and the lack of methods for reliable removal of palladium traces from the final product. In addition to toxicity, the high cost of catalysts based on palladium, as well as another catalyst for pharmaceuticals, platinum, makes the use of copper nanoparticles economically and environmentally justified.

Here’s a link to and a citation for the paper,

Copper nanoparticles as inexpensive and efficient catalyst: A valuable contribution in organic synthesis by Nisha Kant Ojha, Grigory V. Zyryanov, Adinath Majee, Valery N. Charushin, Oleg N. Chupakhin, Sougata Santra. Coordination Chemistry Reviews Volume 353, 15 December 2017, Pages 1-57 https://doi.org/10.1016/j.ccr.2017.10.004

This paper is behind a paywall.

Combining gold and palladium for catalytic and plasmonic octopods

Hopefully I did not the change meaning when I made the title for this piece more succinct. In any event, this research comes from the always prolific Rice University in Texas, US (from a Nov. 30, 2015 news item on Nanotechnology Now),

Catalysts are substances that speed up chemical reactions and are essential to many industries, including petroleum, food processing and pharmaceuticals. Common catalysts include palladium and platinum, both found in cars’ catalytic converters. Plasmons are waves of electrons that oscillate in particles, usually metallic, when excited by light. Plasmonic metals like gold and silver can be used as sensors in biological applications and for chemical detection, among others.

Plasmonic materials are not the best catalysts, and catalysts are typically very poor for plasmonics. But combining them in the right way shows promise for industrial and scientific applications, said Emilie Ringe, a Rice assistant professor of materials science and nanoengineering and of chemistry who led the study that appears in Scientific Reports.

“Plasmonic particles are magnets for light,” said Ringe, who worked on the project with colleagues in the U.S., the United Kingdom and Germany. “They couple with light and create big electric fields that can drive chemical processes. By combining these electric fields with a catalytic surface, we could further push chemical reactions. That’s why we’re studying how palladium and gold can be incorporated together.”

The researchers created eight-armed specks of gold and coated them with a gold-palladium alloy. The octopods proved to be efficient catalysts and sensors.

A Nov. 30, 2015 Rice University news release (also on EurekAlert), which originated the news item, expands on the theme,

“If you simply mix gold and palladium, you may end up with a bad plasmonic material and a pretty bad catalyst, because palladium does not attract light like gold does,” Ringe said. “But our particles have gold cores with palladium at the tips, so they retain their plasmonic properties and the surfaces are catalytic.”

Just as important, Ringe said, the team established characterization techniques that will allow scientists to tune application-specific alloys that report on their catalytic activity in real time.

The researchers analyzed octopods with a variety of instruments, including Rice’s new Titan Themis microscope, one of the most powerful electron microscopes in the nation. “We confirmed that even though we put palladium on a particle, it’s still capable of doing everything that a similar gold shape would do. That’s really a big deal,” she said.

“If you shine a light on these nanoparticles, it creates strong electric fields. Those fields enhance the catalysis, but they also report on the catalysis and the molecules present at the surface of the particles,” Ringe said.

The researchers used electron energy loss spectroscopy, cathodoluminescence and energy dispersive X-ray spectroscopy to make 3-D maps of the electric fields produced by exciting the plasmons. They found that strong fields were produced at the palladium-rich tips, where plasmons were the least likely to be excited.

Ringe expects further research will produce multifunctional nanoparticles in a variety of shapes that can be greatly refined for applications. Her own Rice lab is working on a metal catalyst to turn inert petroleum derivatives into backbone molecules for novel drugs.

Here’s a link to and a citation for the paper,

Resonances of nanoparticles with poor plasmonic metal tips by Emilie Ringe, Christopher J. DeSantis, Sean M. Collins, Martial Duchamp, Rafal E. Dunin-Borkowski, Sara E. Skrabalak, & Paul A. Midgley.  Scientific Reports 5, Article number: 17431 (2015)  doi:10.1038/srep17431 Published online: 30 November 2015

This is an open access paper,

Canadian and Japanese researchers create new technique for using iron nanoparticles in greener hydrogenation process

McGill University’s Audrey Moores and her team’s latest green chemistry work with researchers at RIKEN (The Institute of Physical and Chemical Research, Wako, Japan) and the Institute for Molecular Science (Okazaki, Japan) is featured in a June 27, 2013 news item on Nanowerk,

Researchers from McGill University, RIKEN (The Institute of Physical and Chemical Research, Wako, Japan) and the Institute for Molecular Science (Okazaki, Japan) have discovered a way to make the widely used chemical process of hydrogenation more environmentally friendly – and less expensive.

Hydrogenation is a chemical process used in a wide range of industrial applications, from food products, such as margarine, to petrochemicals and pharmaceuticals. The process typically involves the use of heavy metals, such as palladium or platinum, to catalyze the chemical reaction. While these metals are very efficient catalysts, they are also non-renewable, costly, and subject to sharp price fluctuations on international markets.

Because these metals are also toxic, even in small quantities, they also raise environmental and safety concerns. Pharmaceutical companies, for example, must use expensive purification methods to limit residual levels of these elements in pharmaceutical products. Iron, by contrast, is both naturally abundant and far less toxic than heavy metals.

Previous work by other researchers has shown that iron nanoparticles — tiny pieces of metallic iron — can be used to activate the hydrogenation reaction. Iron, however, has a well-known drawback: it rusts in the presence of oxygen or water. When rusted, iron nanoparticles stop acting as hydrogenation catalysts. This problem, which occurs with so much as trace quantities of water, has prevented iron nanoparticles from being used in industry.

The June 27, 2013 McGill University news release on EurekAlert, which originated the news item, provides details about the new technique,

The key to this new method is to produce the particles directly inside a polymer matrix, composed of amphiphilic polymers based on polystyrene and polyethylene glycol. The polymer acts as a wrapping film that protects the iron surface from rusting in the presence of water, while allowing the reactants to reach the water and react.

This innovation enabled the researchers to use iron nanoparticles as catalyst in a flow system, raising the possibility that iron could be used to replace platinum-series metals for hydrogenation under industrial conditions.

“Our research is now focused on achieving a better understanding of how the polymers are protecting the surface of the iron from water, while at the same time allowing the iron to interact with the substrate,” says Audrey Moores, an assistant professor of chemistry at McGill and co-corresponding author of the paper.

“The approach we have developed through this collaboration could lead to more sustainable industrial processes,” says Prof. Uozumi [Prof. Yasuhiro Uozumi of Riken]. “This technique provides a system in which the reaction can happen over and over with the same small amount of a catalytic material, and it enables it to take place in almost pure water — the green solvent par excellence.”

I last wrote about greener chemistry and iron nanoparticles in a March 28, 2012 posting concerning some work at the University of Toronto while the last time McGill, green chemistry, and Audrey Moores were mentioned here was in a Jan. 10, 2011 posting concerning ‘nanomagnetics.

For those who are interested in this latest work from McGill, here’s a link to and a citation for the published paper,

Highly efficient iron(0) nanoparticle-catalyzed hydrogenation in water in flow by Reuben Hudson, Go Hamasaka, Takao Osako, Yoichi M. A. Yamada, Chao-Jun Li, Yasuhiro Uozumi, and Audrey Moores.
Green Chem., 2013, Advance Article DOI: 10.1039/C3GC40789F

First published online 27 Jun 2013

This paper is behind a paywall.

Nano valentine; Owning the podium and science at the Olympics in French; Introduction to three part interview with Cheryl Geisler

Yesterday, I meant to post about the nano Valentine’s Day card that scientists at Birmingham University’s Nanoscale Physics Research Lab made out of pure palladium. From the university’s  news release (thanks to Azonano where I first spotted this item),

Making the card was also a work of love; clusters of palladium atoms bonded together on the surface of carbon and spontaneously arranged themselves into the world’s smallest heart.

Here’s the card,

Palladium Valentine, 8 nm in size, from Birmingham University's Nanoscale Physics Research Laboratory

Now on to the Vancouver 2010 Olympics, “Own the Podium” or “À nous le podium” and science in a very illuminating podcast (French language) on Je vote pour la science.

I first heard about the “Own the Podium” government sports/science initiative, although not by that name, early last week from a friend in England where it was being discussed in the media. I saw nothing here until the Globe and Mail (G&M) article, Is Canada a Spoilsport? (pp. F1 & F6) by Ian Brown in the Feb. 13, 2010 edition, but I assumed that’s because I don’t follow sports closely. After listening to the Josée Nadia Drouin and Pascal Lapointe (both of Quebec’s Agence Science-Presse) podcast on Je vote pour la science, I realized that the programme has been kept somewhat quiet until lately.

My French comprehension is spotty but I gathered from the podcast that the government devoted some $117M for sports in preparation for the Olympics, from the G&M article that athletes were given a stipend of $18,000 for living expenses (doesn’t sound like much to me), and from the podcast, again, that money was given to 55 Centres of Excellence in 7 universities for scientific research supporting athletic efforts.

I do think that we should better support our athletes but I abhor the programme name,  Own the Podium, which suggests that winning is the prime motive for competing. This is noxious when you consider the intent of the Olympics as expressed by Pierre de Coubertin, the founder of the modern Olympics, (from Wikipedia here citing Christopher R. Hill’s 1996 book Olympic Politics)

The important thing in life is not the triumph but the struggle, the essential thing is not to have conquered but to have fought well.

As for the Olympics and science, Lapointe and Drouin also focused on surveillance. Unfortunately for me, their correspondent was on a poor telephone line and that combined with my French comprehension skills means I got very little data but the conflation of science, surveillance, and sporting events gave me an expanded perspective.

For my final bit today, I’m introducing Dr. Cheryl Geisler, the new dean for the new Faculty of Communication, Art and Technology (FCAT) at Simon Fraser University (Burnaby, Canada). She very kindly gave me an interview in early February about her new faculty and her plans.

I’m providing some background before posting the interview. From the SFU website, the university has approximately 32,000 students and 900 faculty as of the 20007 annual report which contrasts somewhat with Geisler’s previous home institution, Rensselaer Polytechnic Institute (located in Troy, NY with approximately 7700 students and 450 faculty as of Fall 2009. from their website).

I did encounter some difficulty finding numbers of students, faculty and administrative staff for individual departments and faculties (FCAT has five admin staff) at both universities and am not sure if this is innocence (nobody has considered making the information available) or strategy (i.e., universities prefer to keep the information discreet although it can be obtained if you’re willing  [spelling corrected Feb.17.10] to dig deep enough). ETA (Feb.17.10): I was kindly provided with a link to FCAT’s wikipedia entry where I found that there are 1861 undergraduate students and 208 graduate students for a total of 2069 students with 79 continuing full time faculty members. According to the wikipedia entry, this information is available at the SFU website on this page in a category titled Headcounts. It is part of the SFU website which belongs to Institutional Research and Planning.

As for Dr. Geisler herself, she holds a PhD in Rhetoric from Carnegie Mellon University (main campus in Pittsburgh, Pennsylvania), an MS in Reading from Western Illinois University, and a BA in English from Carleton College (Northfield, Minnesota). Prior to her move, she had been affiliated with Rensselaer in one fashion or another since 1986.

The most exotic thing on her CV (obtained from the Rensselaer website in October 2009) is a two year stint in Jerusalem as a teacher of English as a foreign language. She has some experience with Canada as an outside reviewer for the Social Sciences and Humanities Research Council in 2000 for their Valuing Literacy in Canada programme.

Taken as a whole, her CV is an impressive document. At Rensselaer, she taught courses such as Techniques for the Analysis of Verbal Data; Proposing and Persuading; and the Literacy Seminar: Theories of Mediation, Technology and Text. She has written widely and (along with partners) holds two patents in addition to administering federal government grants for a number of different projects.

I cherrypicked, there’s a lot more to Dr. Geisler’s CV but I think the point has been made. Tomorrow (Feb. 17, 2010), I start a three part series, Off the deep end: an interview with Cheryl Geisler Part 1, Part 2, Part 3.