Tag Archives: catalyst

Jiggly jell-o as a new hydrogen fuel catalyst

Jello [uploaded from https://www.organicauthority.com/eco-chic-table/new-jell-o-mold-jiggle-chic-holidays]

I’m quite intrigued by this ‘jell-o’ story. It’s hard to believe a childhood dessert might prove to have an application as a catalyst for producing hydrogen fuel. From a December 14, 2018 news item on Nanowerk,

A cheap and effective new catalyst developed by researchers at the University of California, Berkeley, can generate hydrogen fuel from water just as efficiently as platinum, currently the best — but also most expensive — water-splitting catalyst out there.

The catalyst, which is composed of nanometer-thin sheets of metal carbide, is manufactured using a self-assembly process that relies on a surprising ingredient: gelatin, the material that gives Jell-O its jiggle.

Two-dimensional metal carbides spark a reaction that splits water into oxygen and valuable hydrogen gas. Berkeley researchers have discovered an easy new recipe for cooking up these nanometer-thin sheets that is nearly as simple as making Jell-O from a box. (Xining Zang graphic, copyright Wiley)

A December 13, 2018 University of California at Berkeley (UC Berkeley) news release by Kara Manke (also on EurekAlert but published on Dec. 14, 2018), which originated the news item, provides more technical detail,

“Platinum is expensive, so it would be desirable to find other alternative materials to replace it,” said senior author Liwei Lin, professor of mechanical engineering at UC Berkeley. “We are actually using something similar to the Jell-O that you can eat as the foundation, and mixing it with some of the abundant earth elements to create an inexpensive new material for important catalytic reactions.”

The work appears in the Dec. 13 [2018] print edition of the journal Advanced Materials.

A zap of electricity can break apart the strong bonds that tie water molecules together, creating oxygen and hydrogen gas, the latter of which is an extremely valuable source of energy for powering hydrogen fuel cells. Hydrogen gas can also be used to help store energy from renewable yet intermittent energy sources like solar and wind power, which produce excess electricity when the sun shines or when the wind blows, but which go dormant on rainy or calm days.

A black and white image of metal carbide under high magnification.

When magnified, the two-dimensional metal carbides resemble sheets of cell[o]phane. (Xining Zang photo, copyright Wiley)

But simply sticking an electrode in a glass of water is an extremely inefficient method of generating hydrogen gas. For the past 20 years, scientists have been searching for catalysts that can speed up this reaction, making it practical for large-scale use.

“The traditional way of using water gas to generate hydrogen still dominates in industry. However, this method produces carbon dioxide as byproduct,” said first author Xining Zang, who conducted the research as a graduate student in mechanical engineering at UC Berkeley. “Electrocatalytic hydrogen generation is growing in the past decade, following the global demand to lower emissions. Developing a highly efficient and low-cost catalyst for electrohydrolysis will bring profound technical, economical and societal benefit.”

To create the catalyst, the researchers followed a recipe nearly as simple as making Jell-O from a box. They mixed gelatin and a metal ion — either molybdenum, tungsten or cobalt — with water, and then let the mixture dry.

“We believe that as gelatin dries, it self-assembles layer by layer,” Lin said. “The metal ion is carried by the gelatin, so when the gelatin self-assembles, your metal ion is also arranged into these flat layers, and these flat sheets are what give Jell-O its characteristic mirror-like surface.”

Heating the mixture to 600 degrees Celsius triggers the metal ion to react with the carbon atoms in the gelatin, forming large, nanometer-thin sheets of metal carbide. The unreacted gelatin burns away.

The researchers tested the efficiency of the catalysts by placing them in water and running an electric current through them. When stacked up against each other, molybdenum carbide split water the most efficiently, followed by tungsten carbide and then cobalt carbide, which didn’t form thin layers as well as the other two. Mixing molybdenum ions with a small amount of cobalt boosted the performance even more.

“It is possible that other forms of carbide may provide even better performance,” Lin said.

On the left, an illustration of blue spheres, representing gelatin molecules, arranged in a lattice shape. On the right, an illustration of thin sheets of metal carbide.

Molecules in gelatin naturally self-assemble in flat sheets, carrying the metal ions with them (left). Heating the mixture to 600 degrees Celsius burns off the gelatin, leaving nanometer-thin sheets of metal carbide. (Xining Zang illustration, copyright Wiley)

The two-dimensional shape of the catalyst is one of the reasons why it is so successful. That is because the water has to be in contact with the surface of the catalyst in order to do its job, and the large surface area of the sheets mean that the metal carbides are extremely efficient for their weight.

Because the recipe is so simple, it could easily be scaled up to produce large quantities of the catalyst, the researchers say.

“We found that the performance is very close to the best catalyst made of platinum and carbon, which is the gold standard in this area,” Lin said. “This means that we can replace the very expensive platinum with our material, which is made in a very scalable manufacturing process.”

Co-authors on the study are Lujie Yang, Buxuan Li and Minsong Wei of UC Berkeley, J. Nathan Hohman and Chenhui Zhu of Lawrence Berkeley National Lab; Wenshu Chen and Jiajun Gu of Shanghai Jiao Tong University; Xiaolong Zou and Jiaming Liang of the Shenzhen Institute; and Mohan Sanghasadasa of the U.S. Army RDECOM AMRDEC.

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

Self‐Assembly of Large‐Area 2D Polycrystalline Transition Metal Carbides for Hydrogen Electrocatalysis by Xining Zang, Wenshu Chen, Xiaolong Zou, J. Nathan Hohman, Lujie Yang
Buxuan Li, Minsong Wei, Chenhui Zhu, Jiaming Liang, Mohan Sanghadasa, Jiajun Gu, Liwei Lin. Advanced Materials Volume30, Issue 50 December 13, 2018 1805188 DOI: https://doi.org/10.1002/adma.201805188 First published [online]: 09 October 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.

Watching rust turn into iron

a) Colorized SEM images of iron oxide nanoblades used in the experiment. b) Colorized cross-section of SEM image of the nanoblades. c) Colorized SEM image of nanoblades after 1 hour of reduction reaction at 500 °C in molecular hydrogen, showing the sawtooth shape along the edges (square). d) Colorized SEM image showing the formation of holes after 2 hours of reduction. The scale bar is 1 micrometer. Credit: W. Zhu et al./ACS Nano and K. Irvine/NIST

Here’s more about being able to watch iron transition from one state to the next according to an April 5, 2017 news item on phys.org

Using a state-of-the-art microscopy technique, experimenters at the National Institute of Standards and Technology (NIST) and their colleagues have witnessed a slow-motion, atomic-scale transformation of rust—iron oxide—back to pure iron metal, in all of its chemical steps.

An April 4, 2017 NIST news release describes the role iron plays in modern lifestyles and the purpose of this research,

Among the most abundant minerals on Earth, iron oxides play a leading role in magnetic data storage, cosmetics, the pigmentation of paints and drug delivery. These materials also serve as catalysts for several types of chemical reactions, including the production of ammonia for fertilizer.

To fine-tune the properties of these minerals for each application, scientists work with nanometer-scale particles of the oxides. But to do so, researchers need a detailed, atomic-level understanding of reduction, a key chemical reaction that iron oxides undergo. That knowledge, however, is often lacking because reduction—a process that is effectively the opposite of rusting—proceeds too rapidly for many types of probes to explore at such a fine level.

In a new effort to study the microscopic details of metal oxide reduction, researchers used a specially adapted transmission electron microscope (TEM) at NIST’s NanoLab facility to document the step-by-step transformation of nanocrystals of the iron oxide hematite (Fe2O3) to the iron oxide magnetite (Fe3O4), and finally to iron metal.

“Even though people have studied iron oxide for many years, there have been no dynamic studies at the atomic scale,” said Wenhui Zhu of the State University of New York at Binghamton, who worked on her doctorate in the NanoLab in 2015 and 2016. “We are seeing what’s actually happening during the entire reduction process instead of studying just the initial steps.”

That’s critical, added NIST’s Renu Sharma, “if you want to control the composition or properties of iron oxides and understand the relationships between them.”

By lowering the temperature of the reaction and decreasing the pressure of the hydrogen gas that acted as the reducing agent, the scientists slowed down the reduction process so that it could be captured with an environmental TEM—a specially configured TEM that can study both solids and gas. The instrument enables researchers to perform atomic-resolution imaging of a sample under real-life conditions—in this case the gaseous environment necessary for iron oxides to undergo reduction–rather than under the vacuum needed in ordinary TEMs.

“This is the most powerful tool I’ve used in my research and one of the very few in the United States,” said Zhu. She, Sharma and their colleagues describe their findings in a recent issue of ACS Nano.

The team examined the reduction process in a bicrystal of iron oxide, consisting of two identical iron oxide crystals rotated at 21.8 degrees with respect to each other. The bicrystal structure also served to slow down the reduction process, making it easier to follow with the environmental TEM.

In studying the reduction reaction, the researchers identified a previously unknown intermediate state in the transformation from magnetite to hematite. In the middle stage, the iron oxide retained its original chemical structure, Fe2O3, but changed the crystallographic arrangement of its atoms from rhombohedral (a diagonally stretched cube) to cubic.

This intermediate state featured a defect in which oxygen atoms fail to populate some of the sites in the crystal that they normally would. This so-called oxygen vacancy defect is not uncommon and is known to strongly influence the electrical and catalytic properties of oxides. But the researchers were surprised to find that the defects occurred in an ordered pattern, which had never been found before in the reduction of Fe2O3 to Fe3O4, Sharma said.

The significance of the intermediate state remains under study, but it may be important for controlling the reduction rate and other properties of the reduction process, she adds. “The more we understand, the better we can manipulate the microstructure of these oxides,” said Zhu. By manipulating the microstructure, researchers may be able to enhance the catalytic activity of iron oxides.

Even though a link has already been provided for the paper, I will give it again along with a citation,

In Situ Atomic-Scale Probing of the Reduction Dynamics of Two-Dimensional Fe2O3 Nanostructures by Wenhui Zhu, Jonathan P. Winterstein, Wei-Chang David Yang, Lu Yuan, Renu Sharma, and Guangwen Zhou. ACS Nano, 2017, 11 (1), pp 656–664 DOI: 10.1021/acsnano.6b06950 Publication Date (Web): December 13, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Nano snowman

I guess if people can spot religious figures in their morning toast or in the vegetables and fruits they grow, there’s no reason why scientists shouldn’t be able to see a snowman’s face in a nanoparticle,

Courtesy: University of Birmingham

A Dec. 20, 2016 news item on phys.org describes the nanoparticle,

Scientists at the University of Birmingham have captured the formation of a platinum encrusted nanoparticle that bears a striking resemblance to a festive snowman. As well as providing some Christmas cheer, the fully functional ‘nano-snowman’ has applications for providing greener energy and for advancements in medical care.

A Dec. 20, 2016 University of Birmingham press release, which originated the news item, provides more detail (Note: Links have been removed),

At only five nanometres in size, the nano-snowman was imaged with an aberration-corrected scanning transmission electron microscope at the Nanoscale Physics, Chemistry and Engineering Research Laboratory at the University of Birmingham.

It was formed unexpectedly from a self-assembled platinum-titanium nanoparticle which was oxidised in air, and features ‘eyes, nose and a mouth’ formed of precious-metal platinum clusters embedded in a titanium dioxide face.

Despite its festive appearance, the nano-snowman performs a serious function of catalysing the splitting of water to make green hydrogen for fuel cells. In this functionality the nanoparticle demonstrates how the inclusion of titanium atoms to a platinum catalyst particle has its benefits.

Platinum is highly functional in performing chemical transformations making it a sought after metal for scientific use. It is also expensive and in critical supply. Therefore, the nano-snowman demonstrates how, by including titanium atoms, the amount of platinum needed is reduced and the existing platinum used is protected against sintering (aggregation of the nanoparticles).

Professor Richard Palmer, head of the University’s Nanoscale Physics Research Lab – the first centre for nanoscience in the UK – leads the way in research on nanoparticle science and explains how this information holds great interest for the Energy and Pharmaceutical industries:

“By combining titanium and platinum atoms in a nanoparticle, we can reduce the need to use rare and expensive platinum, and also maintain that which we have used. This could affect a number of applications where platinum is used such as creating green hydrogen for cleaner energy use; generating low energy electrons in radiotherapy that can kill cancer cells; and to perform chemical transformations to create pharmaceutical products.”

Saeed Gholhaki, one of the scientists to discover the snowman says:

“In the nano regime atoms are the building blocks of nanoscale structures. These building blocks can form wonderful shapes and structures regulated by the laws of nature. Nanoscience is about understanding the physics behind, and thus controlling these phenomenon, ultimately allowing us to design materials with desired properties. Sometimes the building blocks, in this case platinum cores, can assemble in an interesting way to resemble familiar objects like the face of a snowman!”

That’s all folks.

Split some water molecules and save solar and wind (energy) for a future day

Professor Ted Sargent’s research team at the University of Toronto has a developed a new technique for saving the energy harvested by sun and wind farms according to a March 28, 2016 news item on Nanotechnology Now,

We can’t control when the wind blows and when the sun shines, so finding efficient ways to store energy from alternative sources remains an urgent research problem. Now, a group of researchers led by Professor Ted Sargent at the University of Toronto’s Faculty of Applied Science & Engineering may have a solution inspired by nature.

The team has designed the most efficient catalyst for storing energy in chemical form, by splitting water into hydrogen and oxygen, just like plants do during photosynthesis. Oxygen is released harmlessly into the atmosphere, and hydrogen, as H2, can be converted back into energy using hydrogen fuel cells.

Discovering a better way of storing energy from solar and wind farms is “one of the grand challenges in this field,” Ted Sargent says (photo above by Megan Rosenbloom via flickr) Courtesy: University of Toronto

Discovering a better way of storing energy from solar and wind farms is “one of the grand challenges in this field,” Ted Sargent says (photo above by Megan Rosenbloom via flickr) Courtesy: University of Toronto

A March 24, 2016 University of Toronto news release by Marit Mitchell, which originated the news item, expands on the theme,

“Today on a solar farm or a wind farm, storage is typically provided with batteries. But batteries are expensive, and can typically only store a fixed amount of energy,” says Sargent. “That’s why discovering a more efficient and highly scalable means of storing energy generated by renewables is one of the grand challenges in this field.”

You may have seen the popular high-school science demonstration where the teacher splits water into its component elements, hydrogen and oxygen, by running electricity through it. Today this requires so much electrical input that it’s impractical to store energy this way — too great proportion of the energy generated is lost in the process of storing it.

This new catalyst facilitates the oxygen-evolution portion of the chemical reaction, making the conversion from H2O into O2 and H2 more energy-efficient than ever before. The intrinsic efficiency of the new catalyst material is over three times more efficient than the best state-of-the-art catalyst.

Details are offered in the news release,

The new catalyst is made of abundant and low-cost metals tungsten, iron and cobalt, which are much less expensive than state-of-the-art catalysts based on precious metals. It showed no signs of degradation over more than 500 hours of continuous activity, unlike other efficient but short-lived catalysts. …

“With the aid of theoretical predictions, we became convinced that including tungsten could lead to a better oxygen-evolving catalyst. Unfortunately, prior work did not show how to mix tungsten homogeneously with the active metals such as iron and cobalt,” says one of the study’s lead authors, Dr. Bo Zhang … .

“We invented a new way to distribute the catalyst homogenously in a gel, and as a result built a device that works incredibly efficiently and robustly.”

This research united engineers, chemists, materials scientists, mathematicians, physicists, and computer scientists across three countries. A chief partner in this joint theoretical-experimental studies was a leading team of theorists at Stanford University and SLAC National Accelerator Laboratory under the leadership of Dr. Aleksandra Vojvodic. The international collaboration included researchers at East China University of Science & Technology, Tianjin University, Brookhaven National Laboratory, Canadian Light Source and the Beijing Synchrotron Radiation Facility.

“The team developed a new materials synthesis strategy to mix multiple metals homogeneously — thereby overcoming the propensity of multi-metal mixtures to separate into distinct phases,” said Jeffrey C. Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems at Massachusetts Institute of Technology. “This work impressively highlights the power of tightly coupled computational materials science with advanced experimental techniques, and sets a high bar for such a combined approach. It opens new avenues to speed progress in efficient materials for energy conversion and storage.”

“This work demonstrates the utility of using theory to guide the development of improved water-oxidation catalysts for further advances in the field of solar fuels,” said Gary Brudvig, a professor in the Department of Chemistry at Yale University and director of the Yale Energy Sciences Institute.

“The intensive research by the Sargent group in the University of Toronto led to the discovery of oxy-hydroxide materials that exhibit electrochemically induced oxygen evolution at the lowest overpotential and show no degradation,” said University Professor Gabor A. Somorjai of the University of California, Berkeley, a leader in this field. “The authors should be complimented on the combined experimental and theoretical studies that led to this very important finding.”

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

Homogeneously dispersed, multimetal oxygen-evolving catalysts by Bo Zhang, Xueli Zheng, Oleksandr Voznyy, Riccardo Comin, Michal Bajdich, Max García-Melchor, Lili Han, Jixian Xu, Min Liu, Lirong Zheng, F. Pelayo García de Arquer, Cao Thang Dinh, Fengjia Fan, Mingjian Yuan, Emre Yassitepe, Ning Chen, Tom Regier, Pengfei Liu, Yuhang Li, Phil De Luna, Alyf Janmohamed, Huolin L. Xin, Huagui Yang, Aleksandra Vojvodic, Edward H. Sargent. Science  24 Mar 2016: DOI: 10.1126/science.aaf1525

This paper is behind a paywall.

Hybrid bacterial genes and virus shell combined to create ‘nano reactor’ for hydrogen biofuel

Turning water into fuel may seem like an almost biblical project (e.g., Jesus turning water to wine in the New Testament) but scientists at Indiana University are hopeful they are halfway to their goal. From a Jan. 4, 2016 news item on ScienceDaily,

Scientists at Indiana University have created a highly efficient biomaterial that catalyzes the formation of hydrogen — one half of the “holy grail” of splitting H2O to make hydrogen and oxygen for fueling cheap and efficient cars that run on water.

A Jan. 4, 2016 Indiana University (IU) news release (also on EurekAlert*), which originated the news item, explains further (Note: Links have been removed),

A modified enzyme that gains strength from being protected within the protein shell — or “capsid” — of a bacterial virus, this new material is 150 times more efficient than the unaltered form of the enzyme.

“Essentially, we’ve taken a virus’s ability to self-assemble myriad genetic building blocks and incorporated a very fragile and sensitive enzyme with the remarkable property of taking in protons and spitting out hydrogen gas,” said Trevor Douglas, the Earl Blough Professor of Chemistry in the IU Bloomington College of Arts and Sciences’ Department of Chemistry, who led the study. “The end result is a virus-like particle that behaves the same as a highly sophisticated material that catalyzes the production of hydrogen.”

The genetic material used to create the enzyme, hydrogenase, is produced by two genes from the common bacteria Escherichia coli, inserted inside the protective capsid using methods previously developed by these IU scientists. The genes, hyaA and hyaB, are two genes in E. coli that encode key subunits of the hydrogenase enzyme. The capsid comes from the bacterial virus known as bacteriophage P22.

The resulting biomaterial, called “P22-Hyd,” is not only more efficient than the unaltered enzyme but also is produced through a simple fermentation process at room temperature.

The material is potentially far less expensive and more environmentally friendly to produce than other materials currently used to create fuel cells. The costly and rare metal platinum, for example, is commonly used to catalyze hydrogen as fuel in products such as high-end concept cars.

“This material is comparable to platinum, except it’s truly renewable,” Douglas said. “You don’t need to mine it; you can create it at room temperature on a massive scale using fermentation technology; it’s biodegradable. It’s a very green process to make a very high-end sustainable material.”

In addition, P22-Hyd both breaks the chemical bonds of water to create hydrogen and also works in reverse to recombine hydrogen and oxygen to generate power. “The reaction runs both ways — it can be used either as a hydrogen production catalyst or as a fuel cell catalyst,” Douglas said.

The form of hydrogenase is one of three occurring in nature: di-iron (FeFe)-, iron-only (Fe-only)- and nitrogen-iron (NiFe)-hydrogenase. The third form was selected for the new material due to its ability to easily integrate into biomaterials and tolerate exposure to oxygen.

NiFe-hydrogenase also gains significantly greater resistance upon encapsulation to breakdown from chemicals in the environment, and it retains the ability to catalyze at room temperature. Unaltered NiFe-hydrogenase, by contrast, is highly susceptible to destruction from chemicals in the environment and breaks down at temperatures above room temperature — both of which make the unprotected enzyme a poor choice for use in manufacturing and commercial products such as cars.

These sensitivities are “some of the key reasons enzymes haven’t previously lived up to their promise in technology,” Douglas said. Another is their difficulty to produce.

“No one’s ever had a way to create a large enough amount of this hydrogenase despite its incredible potential for biofuel production. But now we’ve got a method to stabilize and produce high quantities of the material — and enormous increases in efficiency,” he said.

The development is highly significant according to Seung-Wuk Lee, professor of bioengineering at the University of California-Berkeley, who was not a part of the study.

“Douglas’ group has been leading protein- or virus-based nanomaterial development for the last two decades. This is a new pioneering work to produce green and clean fuels to tackle the real-world energy problem that we face today and make an immediate impact in our life in the near future,” said Lee, whose work has been cited in a U.S. Congressional report on the use of viruses in manufacturing.

Beyond the new study, Douglas and his colleagues continue to craft P22-Hyd into an ideal ingredient for hydrogen power by investigating ways to activate a catalytic reaction with sunlight, as opposed to introducing elections using laboratory methods.

“Incorporating this material into a solar-powered system is the next step,” Douglas said.

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

Self-assembling biomolecular catalysts for hydrogen production by Paul C. Jordan, Dustin P. Patterson, Kendall N. Saboda, Ethan J. Edwards, Heini M. Miettinen, Gautam Basu, Megan C. Thielges, & Trevor Douglas. Nature Chemistry (2015) doi:10.1038/nchem.2416 Published online 21 December 2015

This paper is behind a paywall.

*(also on EurekAlert) added on Jan. 5, 2016 at 1550 PST.

Nanoscale snowman and Season’s Greetings

It’s being described as a ‘jeweled nano-snowman’ but platinum and titanium aren’t my idea of jewels. Still, it’s a cheerful, seasonal greeting.

Courtesy of the University of Birmingham Nanoscale Physics Research Laboratory

Courtesy of the University of Birmingham Nanoscale Physics Research Laboratory

A December 22, 2015 news item on Nanowerk tells more of the story,

Would a jewel-encrusted snowman make the perfect Christmas present? At only 5 nanometres in size, the price might be lower than you think. And it’s functional too, catalysing the splitting of water to make green hydrogen for fuel cells.

A December 22, 2015 University of Birmingham Nanoscale Physics Research Laboratory (NPRL) press release, which originated the news item, provides more detail,

The nanoparticle, as imaged with an aberration-corrected scanning transmission electron microscope, features eyes, nose and mouth of precious-metal platinum clusters embedded in a titanium dioxide face. Each platinum cluster typically contains 30 platinum atoms; within the whole nanoparticle there are approximately 1,680 titanium atoms and 180 platinum atoms. The nano-snowman formed spontaneously from a self-assembled platinum-titanium nanoparticle which was oxidised in air, drawing the titanium atoms out to the surface. The self-assembly occurred in a gas phase, cluster beam condensation source, before size-selection with a mass spectrometer and deposition onto a carbon surface for oxidation and then imaging. The mass of the snowman is 120,000 atomic mass units. Compared with a more conventional pure platinum catalyst particle, the inclusion of the titanium atoms offers two potential benefits: dilution of how much precious platinum is needed to perform the catalysis, and protection of the platinum cores against sintering (i.e. aggregation of the nanoparticles). The shell is porous enough to allow hydrogen through and the particles are functional in the hydrogen evolution reaction. The research was performed at the Nanoscale Physics Research Lab by Caroline Blackmore and Ross Griffin. …

The scientists did a little bit of work adding colour (most of these images are gray on gray), as well as, the holly and berry frame.

Joyeux Noël et Bonne Année or Season’s Greetings!

Gold, acetic acid, and proton shuttles

I think the information has been taken from Russian to English by a machine translator, as well, I’m not a chemist, so please bear with my interpretation. It seems that Russian researchers have determined why gold, inert at the macroscale, is a good catalyst at the nanoscale. From a July 28, 2015 news item on Azonano,

Being found mostly in the native state, gold is one of the oldest elements known to man. The affection to gold was determined by it’s unusual properties – heft, shine and ability to withstand oxidation and corrosion.

The combination of properties determined gold use in the jewelry and as a coinage metal. The ancient alchemists working with gold were struggled by utmost chemical resistance of this element – it did not react with concentrated acids or alkali solutions even at high temperatures. Actually, it is the chemical inertness that makes gold to appear in a native form and not as a part of a mineral.

Later analysis established that gold compounds can not only compete with traditional nickel and palladium-based catalysts in the common reactions, but to surpass them. Besides that, gold compounds often demonstrated principally novel types of reactivity compared to well-established catalysts. This allowed chemists to discover a bunch of new chemical reactions and predetermined a fascinating boom in gold catalysis that we have observed in the recent years.

A July 24, 2015 Institute of Organic Chemistry, Russian Academy of Sciences press release on EurekAlert, which also originated the news item, reveals more about the study,

Professor Ananikov and co-workers introduced gold into well-known catalytic system which led to dramatic change of the reactivity and furnished the formation of novel gold-containing complexes. The complexes appeared to be air stable and were isolated in the individual state. A single crystal X-Ray diffraction study ascertained the existence of unique structural motif in the molecule, which can not be explained within conventional mechanistic framework.

The study was carried out using both theoretical and experimental approaches. Dedicated labeling of the reagents allowed observation of molecular re-organizations. Variation of reaction conditions helped to estimate key factors governing the discovered transformation. In addition, computational study of the reaction provided the models of certain intermediate steps, which were invisible for experimental investigation. The theoretical data obtained was in excellent agreement with experiment, proposing the reaction mechanism, where a molecule of acetic acid serves as a proton shuttle, transferring the hydrogen atom between the reaction centers.

The belief of gold inactivity towards chemical transformations resulted in the fact, that organometallic chemistry of gold was developed significantly later compared to other coinage metals (like silver, nickel or copper). Today, our goal is to “introduce gold catalysis as a valuable practical tool in fine organic chemistry, competitive with other transition metal catalysts”, says Prof. Ananikov.

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

Carboxylic Group-Assisted Proton Transfer in Gold-Mediated Thiolation of Alkynes by Sergey S. Zalesskiy, Victor N. Khrustalev, Alexandr Yu. Kostukovich, and Valentine P. Ananikov. Organometallics, Article ASAP DOI: 10.1021/acs.organomet.5b00210 Publication Date (Web): July 22, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Gold nanoparticles and the air that you breathe

Scientists at the (US Dept. of Energy) Brookhaven National Laboratory can turn gold nanoparticles into catalysts using a room temperature process. From the June 11, 2013 news item on ScienceDaily,

Gold bars may signify great wealth, but the precious metal packs a much more practical punch when shrunk down to just billionths of a meter. Unfortunately, unlocking gold’s potential often requires complex synthesis techniques that produce delicate structures with extreme sensitivity to heat.

Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have discovered a process of creating uniquely structured gold-indium nanoparticles that combine high stability, great catalytic potential, and a simple synthesis process. The new nanostructures — detailed online June 10 in the Proceedings of the National Academy of Sciences — might enhance many different commercial and industrial processes, including acting as an efficient material for catalytic converters in cars.

“We discovered a room-temperature process that transforms a simple alloy into a nanostructure with remarkable properties,” said physicist Eli Sutter, lead author on the study. “By exposing the gold-indium alloy nanoparticles to air, ambient oxygen was able to drive an oxidation reaction that converted them into an active core-shell structure.”

The Brookhaven National Laboratory June 11, 2013 news release, which originated the news item, explains the issues with gold nanoparticles and how the ‘room temperature’ discovery was made,

The Brookhaven Lab researchers were studying oxidation processes through which metals and alloys combine with oxygen when they made the discovery. For this study, they examined alloys of a noble metal and a non-noble metal through a remarkably simple reaction technique: giving gold-indium nanoparticles a little room to breathe. Once nanoparticles of the metal alloy were exposed to oxygen, highly reactive shells of gold-indium oxide formed across their surfaces.

“Conventional wisdom would say that oxidation should push the gold atoms into the center while pulling the less noble indium to the surface, creating a noble metal core that is surrounded by a shell of non-reactive indium-oxide,” Peter Sutter said. “Instead, the oxygen actually penetrated the alloy. After oxidation, the alloy core of the nanoparticles was encapsulated by a newly formed thin shell of mixed gold-indium oxide.”

Trapping gold in the amorphous oxide shell retains its catalytic properties and prevents the gold from sintering and becoming inert. The new nanostructures proved capable of converting oxygen and carbon monoxide into carbon dioxide, demonstrating their activity as a catalyst.

“The indium and gold in the shell are not mobile, but are frozen in the amorphous, oxide,” Eli Sutter said. “Importantly, the structural integrity holds without sintering at temperatures of up to 300 degrees Celsius, making these remarkably resilient compared to other gold nanocatalysts.”

The research was conducted at Brookhaven Lab’s Center for Functional Nanomaterials (CFN), whose unique facilities for nanoscale synthesis and characterization proved central to the discovery of this new process.

“The CFN brings a wide range of state-of-the-art instruments and expertise together under one roof, accelerating research and facilitating collaboration,” Eli Sutter said. “We used transmission electron microscopy to characterize the structures and their composition, x-ray photoelectron spectroscopy to determine the chemical bonding at the surface, and ion-scattering spectroscopy to identify the outermost atoms of the nanoparticle shell.”

Further investigations will help determine the properties of the gold-indium oxide particles in different catalytic reactions, and the same oxidation process will be applied to other metal alloys to create an entire family of new functional materials.

You can find a citation and a link to the researchers’ paper if you click on the ScienceDaily news item link earlier in this posting.