Ruhr-University Bochum (RUB) scientists have been able to observe the smallest details of hydrogen production with the synthetic mineral pentlandite. This makes it possible to develop strategies for the design of robust and cost-effective catalysts for hydrogen production.

The working groups of Prof. Wolfgang Schuhmann and Dr. Ulf-Peter Apfel from the RUB and the team headed by Prof. Patrick R. Unwin from the University of Warwick have reported their work with publication in the journal Angewandte Chemie.

The team from Bochum in the laboratory: Tsvetan Tarnev, Corina Andronescu and Mathias Smialkowski (from the left).  Image Credit: Ruhr-University Bochum. Click image for the largest view.

Hydrogen gas is considered a possible future source of energy and can be produced from water using platinum catalysts and electricity. However, alternative catalysts made of cheaper and more readily available materials with equally high efficiency are barely known.

There are a number of materials that, like platinum, are able to catalyze the reaction of water into hydrogen. “These include metal chalcogenides such as the mineral pentlandite, which is just as efficient as platinum and is also significantly more stable towards catalyst poisons such as sulfur,” explained Ulf-Peter Apfel. Pentlandite consists of iron, nickel and sulfur. Its structure is similar to that of the catalytic centers of hydrogen-producing enzymes found in a variety of sources, including green algae.

In the current study, the researchers investigated the hydrogen production rates of artificially prepared crystalline surfaces of the mineral pentlandite in a drop of liquid with a diameter of a few hundred nanometres. They used scanning electrochemical cell microscopy for this purpose.

This enabled them to clarify how the structure and composition of the material influence the electrocatalytic properties of iron-nickel sulfide. Even the smallest changes in the ratio between iron and nickel by varying the synthesis conditions or the ageing of the material considerably changed the activity in the electrochemical hydrogen formation. “With these findings, we can now continue to work and develop strategies to improve many more robust and cheap catalysts,” said Ulf-Peter Apfel.

The researchers also showed that scanning electrochemical cell microscopy makes it possible to link information on the structure, composition and electrochemical activity of the materials in a spatially resolved manner. The method thus makes it possible to design catalysts specifically and to produce highly active materials this way. “In future, this method will therefore play an important role in the search for electrocatalytically active, heterogeneous catalysts,” said Wolfgang Schuhmann.

The pentlandite sounds very interesting. It can be made from lots less expensive ingredients. One day somebody is going to find a drop in tablet that just fizzes free hydrogen and is super cheap. Meanwhile that energy cost still hovers and the storage wall remains. But hydrogen will come as the discoveries mount up. The technique here might just be the long term payoff. Watching the electrolysis in real time will help a great deal.

Boston College researchers have applied a ‘water-in-salt’ electrolyte that enables stable operation of a lithium-air battery, offers superior long cycle lifetimes and presents a platform that could help lithium-ion batteries achieve their full potential.

This news finally comes after more than two decades of research where improvements to lithium-ion batteries have stalled short of their theoretical potential. As an electrochemical energy storage technology, upgrading performance requires improved stability of electrolytes. Harnessing the full electrochemical power of lithium-oxygen batteries requires an efficient, more stable electrolyte.

The team found a way around the problem of instability that arises from the use of water in the development of aqueous electrolytes.

Image Credit: Boston College. Click Image for the largest view.

In an effort to find a suitable electrolyte system, the team’s water-in-salt approach involves no organic solvents. It consists of super-concentrated lithium salt, known as LiTFSI, in which water molecules lock onto the ions and experience less degradation when in contact with oxygen molecules, according to the researchers, led by Boston College Professor of Chemistry Dunwei Wang.

Wang said, “We employed an unorthodox approach of using a water-based electrolyte for Li-O2 batteries. Previously, water was thought to be extremely bad for Li-O2 battery operations because it would promote parasitic chemical reactions to significantly undermine the desired chemistry. We discovered that when the salt concentration is high, most water molecules can be locked down so that they provide the right functionalities such as conductivity but exhibit little of the parasitic chemical reactions.”

The result is a “highly effective electrolyte that permits stable Li-O2 battery operations on the cathode with superior cycle lifetimes,” the team reported in the journal Chem with the article titled “Cathodically Stable Li-O2 Battery Operations Using Water-In-Salt Electrolyte.” Experiments showed the electrolyte enables stable lithium-air battery operations up to 300 cycles, making it competitive for practical applications.

The team sought to overcome the limitations that have plagued earlier efforts to tame the complex chemical reactions within lithium-air battery prototypes, said Wang, who conducted the project with Boston College researchers Qi Dong, Xiahui Yao, Yanyan Zhao, Miao Qi, Xizi Zhang and Yumin He, and Hongyu Sun from the Technical University of Denmark.

“We studied a new concept for Li-O2 batteries,” said Wang. “We used a combination of electrochemistry and materials characterization tools to carry out the study. Our goal is to enable stable, high-performance Li-O2 battery operations.”

Wang said the researchers will next try to build upon the results for practical fuel cell applications and also work to reduce the cost of producing the electrolyte.

Lithium air technology has immense potential along with implied safety. Perhaps this lab specimen is a breakthrough. More research and testing is in order to illuminate the path to scaling up. Lets hope the progress is rapid, the cycle lifetime improves, and the result is low cost.

Sandia National Laboratories and University of New Mexico researchers have designed a series of nanoscopic membranes made of water saturated by an enzyme that empties coal smoke of CO2 more cheaply and efficiently than any known technology. The enzyme the team found to make the biologically inspired membrane is one naturally developed over millions of years to clear CO2.

The patented work, the paper of which has been published in Nature Communications, has interested power and energy companies that would like to significantly and inexpensively reduce emissions of carbon dioxide, one of the most widespread “greenhouse gases”, and explore other possible uses of the invention.

Researchers term the membrane a “memzyme” because it acts like a filter but is near-saturated with an enzyme, carbonic anhydrase, developed by living cells over millions of years to help rid themselves of carbon dioxide efficiently and rapidly.

The new memzyme meets the Department of Energy’s standards by capturing 90 percent of power plant carbon dioxide production at a relatively low cost of $40 per ton.

Enzymatic liquid membrane design and mechanism of carbon dioxide capture and separation. The Sandia/University of New Mexico membrane is fabricated by formation of 8-nanometer diameter mesopores. Using atomic layer deposition and oxygen plasma processing, the silica mesopores are engineered to be hydrophobic except for an 18-nm-deep region at the pore surface which is hydrophilic. Through capillary condensation, carbonic anhydrase enzymes and water spontaneously fill the hydrophilic mesopores to form an array of stabilized enzymes with an effective concentration greater than 10 times of that achievable in solution. These catalyze the capture and dissolution of carbon dioxide at the upstream surface and the regeneration of carbon dioxide at the downstream surface. The high enzyme concentration and short diffusion path maximizes capture efficiency and flux. Image Credit: Sandia National Laboratories. Click image for the largest view.

Jeff Brinker, a Sandia fellow, University of New Mexico regents’ professor and the paper’s lead author said, “To date, stripping carbon dioxide from smoke has been prohibitively expensive using the thick, solid, polymer membranes currently available. Our inexpensive method follows nature’s lead in our use of a water-based membrane only 18 nanometers thick that incorporates natural enzymes to capture 90 percent of carbon dioxide released. (A nanometer is about 1/700 of the diameter of a human hair.) This is almost 70 percent better than current commercial methods, and it’s done at a fraction of the cost.”

Coal power plants are one of the United States’ largest energy producers, but they have been criticized by some for sending more carbon dioxide into the atmosphere than any other form of electrical power generation. Still, coal burning in China, India and other countries means that U.S. abstinence alone is not likely to solve the world’s climate problems. But, Brinker said, “maybe technology will.”

The memzyme’s formation begins with a drying process called evaporation-induced self-assembly, first developed at Sandia by Brinker 20 years ago and a field of study in its own right.

The procedure creates a close-packed array of silica nanopores designed to accommodate the carbonic anhydrase enzyme and keep it stable. This is done in several steps. First, the array, which may be 100 nanometers long, is treated with a technique called atomic layer deposition to make the nanopore surface water-averse or hydrophobic. This is followed by an oxygen plasma treatment that overlays the water-averse surface to make the nanopores water-loving or hydrophilic, but only to a depth of 18 nanometers. A solution of the enzyme and water spontaneously fill up and are stabilized within the water-loving portion of the nanopores. This creates membranes of water 18 nanometers thick, with a carbonic anhydrase concentration 10 times greater than aqueous solutions made to date.

The solution, at home in its water-loving sleeve, is stable. But because of the enzyme’s ability to rapidly and selectively dissolve carbon dioxide, the catalytic membrane has the capability to capture the overwhelming majority of carbon dioxide molecules that brush up against it from a rising cloud of coal smoke. The hooked molecules then pass rapidly through the membranes, driven solely by a naturally occurring pressure gradient caused by the large number of carbon dioxide molecules on one side of the membrane and their comparative absence on the other.

The chemical process turns the gas briefly into carbonic acid and then bicarbonate before exiting immediately downstream as carbon dioxide gas. The gas can be harvested with 99 percent purity – so pure that it could be used by oil companies for resource extraction. Other molecules pass by the membrane’s surface undisturbed. The enzyme is reusable, and because the water serves as a medium rather than an actor, does not need replacement.

Except the nanopores dry out over long periods of time due to evaporation. But this will be compensated by water vapor rising from lower water baths already installed in power plants to reduce sulfur emissions. And, enzymes damaged from use over time can easily be replaced.

Brinker noted, “The very high concentration of carbonic anhydrase, along with the thinness of the water channel, result in very high carbon dioxide flux through the membrane. The greater the carbonic anhydrase concentration, the greater the flux. The thinner the membrane, the greater the flux.”

The membrane’s arrangement in a generating station’s flue would be like that of a catalytic converter in a car, suggested Brinker. The membranes would sit on the inner surface of a tube arranged like a honeycomb. The flue gas would flow through the membrane-embedded tube, with a carbon dioxide-free gas stream on the outside of the tubes. Varying the tube length and diameter would optimize the carbon dioxide extraction process.

Susan Rempe, Sandia researcher and co-author, is who suggested and developed the idea of inserting carbonic anhydrase into the water solution to improve the speed by which carbon dioxide could be taken up and released from the membrane. She said, “The enzyme can catalyze the dissolution of a million carbon dioxide molecules per second, vastly improving the speed of the process. With optimization by industry, the memzyme could make electricity production cheap and green.”

The press release suggested the separation process could increase the amount of fuel obtained during enhanced oil recovery using carbon dioxide injected into existing reservoirs. There are many other uses possible.

Rempe also noted a slightly different enzyme, used in the same process, can convert methane – an even more potent greenhouse gas – to the more soluble methanol for removal.

University of New Mexico professor and paper co-author Ying-Bing Jiang, is who originated and developed the idea of using watery membranes based on the human body’s processes to separate out carbon dioxide. He noted prior cleansing by industrial scrubbers means that the rising smoke will be clean enough not to significantly impair membrane efficiency and that the membranes have operated efficiently in laboratory settings for months.

The press release also noted that the technology could also sequester carbon dioxide on a spacecraft, the authors mention, because the membranes operate at ambient temperatures and are driven solely by chemical gradients.

This is a technological breakthrough and if it scales up to industrial proportions could very well revolutionize the basic energy structure of the world’s economy. A gallon or about 6.3 pounds of gasoline at this writing is worth at wholesale $2.07/6.3 = $.3236 per pound or an imperial ton is worth $647.14. That leaves about $600 to work the CO2 back into a fuel.

Something is bound to happen with this. CO2 to CO is progressing, too, and that springs lots more opportunities. Might want one of these for my car someday, after all a gallon of gas yields about 20 pounds of CO2.

If this works out these folks are scientific heroes.

University of Notre Dame researchers have developed a renewable energy approach for synthesizing ammonia. Ammonia is crucial for the world’s agricultural production because its an essential nitrogen component of fertilizers that support the world’s food and fuel production needs.

The industrial Haber-Bosch process developed in the early 1900s for producing ammonia relies on non-renewable fossil fuels and has limited applications for only large centralized chemical plants.

The new process, reported with publication in Nature Catalysis, utilizes a plasma – an ionized gas – in combination with non-noble metal catalysts to generate ammonia at much milder conditions than is possible with Haber-Bosch. The energy in the plasma excites nitrogen molecules, one of the two components that go into making ammonia, allowing them to react more readily on the catalysts. Because the energy for the reaction comes from the plasma rather than high heat and intense pressure, the process can be carried out at small scale. This makes the new process well-suited for use with intermittent renewable energy sources and for distributed ammonia production.

Experimental set-up consisting of an L-shaped quartz tube DBD plasma reactor with 5 mm inner diameter tube and an optical fiber coupled to a spectrometer. The bottom part of the L-bend has a quartz window for easy optical access to the catalyst bed. Image Credit: University of Notre Dame. Click image for the largest view.

William Schneider, H. Clifford and Evelyn A. Brosey Professor of Engineering, affiliated member of ND Energy and co-author of the study explained, “Plasmas have been considered by many as a way to make ammonia that is not dependent on fossil fuels and had the potential to be applied in a less centralized way. The real challenge has been to find the right combination of plasma and catalyst. By combining molecular models with results in the laboratory, we were able to focus in on combinations that had never been considered before.”

The research team led by Schneider; David Go, Rooney Family Associate Professor of Engineering in aerospace and mechanical engineering; and Jason Hicks, associate professor of chemical and biomolecular engineering, discovered that because the nitrogen molecules are activated by the plasma, the requirements on the metal catalysts are less stringent, allowing less expensive materials to be used throughout the process. This approach overcomes fundamental limits on the heat-driven Haber-Bosch process, allowing the reaction to be carried out at Haber-Bosch rates at much milder conditions.

Professor Hicks said, “The goal of our work was to develop an alternative approach to making ammonia, but the insights that have come from this collaboration between our research groups can be applied to other difficult chemical processes, such as converting carbon dioxide into a less harmful and more useful product. As we continue studying plasma-ammonia synthesis, we will also consider how else plasma and catalysts could benefit other chemical transformations.”

This technology could very well have a great effect on food and fuel production worldwide. The basics of nitrogen and hydrogen formed up in ammonia is a key to sustainable populations that occupy the planet now. Driving to more fertilizer thus more and better food and fuel stocks are key to improving living standards and thus getting the population growth rate down.

One almost overlooks the reduction in huge amount of natural gas used in the commercial Haber-Bosch process. There remains the question of the new process’s source for the hydrogen. There remains a way to go with this technology.

National University of Singapore (NUS) scientists have developed an economical and industrially viable strategy to produce graphene. The new technique addresses the long-standing challenge of an efficient process for large-scale production of graphene, and offers production potential for sustainable synthesis of the material.

Image of the printed graphene aerogel (200 mg, 50 mg cm−3) supporting 2500 times of its weight. Image Credit: Nature Communications. Click image for the largest view.

The research was conducted in collaboration with Fudan University and the findings were published in prestigious scientific journal Nature Communications.

Graphene is a two-dimensional material with a honeycomb structure of only one atom’s thickness. Expected to be a material of the future, graphene exhibits unique electronic properties that can potentially be employed for a wide range of applications such as touch screens, conductive inks and fast-charging batteries. The difficulty to produce high-quality graphene affordably on a large scale, however, continues to pose a hindrance to its widespread adoption by industries.

The conventional method of producing graphene utilizes sound energy or shearing forces to exfoliate graphene layers from graphite, and then dispersing the layers in very large amounts of organic solvent. Using insufficient solvent causes the graphene layers to reattach themselves back into graphite. Today a yield of one kilogram of graphene requires at least one metric ton of organic solvent, making the method costly and quite environmentally unfriendly.

The NUS-led developmental research team, on the other hand, uses up to 50 times less solvent. This is achieved by exfoliating pre-treated graphite under a highly alkaline condition to trigger flocculation, a process in which the graphene layers continuously cluster together to form graphene slurry without having to increase the volume of solvent. The method also introduces electrostatic repulsive forces between the graphene layers and prevents them from reattaching themselves.

The resulting graphene slurry be easily separated into monolayers when required or stored away for months. The slurry can also be used directly to 3D-print conductive graphene aerogels, an ultra-lightweight sponge-like material that can be used to remove oil spill in the sea.

Professor Loh Kian Ping from the Department of Chemistry at NUS Faculty of Science who is also the Head of 2D Materials Research at the NUS Center for Advanced 2D Materials led the research.

He said, “We have successfully demonstrated a unique exfoliation strategy for preparing high quality graphene and its composites. Our technique, which produces a high yield of crystalline graphene in the form of a concentrated slurry with a significantly smaller volume of solvent, is an attractive solution for industries to carry out large scale synthesis of this promising material in a cost-effective and sustainable manner.”

Its quite likely this technology is going to change the outlook for graphene marketing. So far graphene has been a laboratory item with lots of news and ideas. Perhaps now that the quantity can increase dramatically, graphene may get into some products. But ultimately there is going to need to be a race to the lowest cost provider and we finally have that first step. This is progress.