First Fully Rechargeable Carbon Dioxide Battery is Seven Times More Efficient Than Lithium Ion


CO2 Battery 1 Unmarked-Batteries-Public-Domain-via-Pxhere

Carbon Dioxide Battery is Seven Times More Efficient Than Lithium Ion

Lithium-carbon dioxide batteries are attractive energy storage systems because they have a specific energy density that is more than seven times greater than commonly used lithium-ion batteries. Until now, however, scientists have not been able to develop a fully rechargeable prototype, despite their potential to store more energy.

Researchers at the University of Illinois at Chicago are the first to show that lithium-carbon dioxide batteries can be designed to operate in a fully rechargeable manner, and they have successfully tested a lithium-carbon dioxide battery prototype running up to 500 consecutive cycles of charge/recharge processes.

Their findings are published in the journal Advanced Materials.

“Lithium-carbon dioxide batteries have been attractive for a long time, but in practice, we have been unable to get one that is truly efficient until now,” said Amin Salehi-Khojin, associate professor of mechanical and industrial engineering at UIC’s College of Engineering.

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Traditionally, when a lithium-carbon dioxide battery discharges, it produces lithium carbonate and carbon. The lithium carbonate recycles during the charge phase, but the carbon just accumulates on the catalyst, ultimately leading to the battery’s failure.

rechargeable-carbon-dioxide-battery

Lithium–CO2 batteries are attractive energy‐storage systems for fulfilling the demand of future large‐scale applications such as electric vehicles due to their high specific energy density.

“The accumulation of carbon not only blocks the active sites of the catalyst and prevents carbon dioxide diffusion, but also triggers electrolyte decomposition in a charged state,” said Alireza Ahmadiparidari, first author of the paper and a UIC College of Engineering graduate student.

Salehi-Khojin and his colleagues used new materials in their experimental carbon dioxide battery to encourage the thorough recycling of both lithium carbonate and carbon. They used molybdenum disulfide as a cathode catalyst combined with a hybrid electrolyte to help incorporate carbon in the cycling process.

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Specifically, their combination of materials produces a single multi-component composite of products rather than separate products, making recycling more efficient.

“Our unique combination of materials helps make the first carbon-neutral lithium carbon dioxide battery with much more efficiency and long-lasting cycle life, which will enable it to be used in advanced energy storage systems,” Salehi-Khojin said.

This research was supported, in part, by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, and a grant from the National Science Foundation.

Reprinted from the University of Illinois-Chicago

Converting CO2 to Valuable Resources (ethanol and propanol) with the help of Nanoparticles


Ruhr CO2 1 2019_09_27_schuhmann_jacs_tk_01

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. Scientists at Ruhr-Universität Bochum in Germany and the University of New South Wales in Australia have adopted the principle from enzymes that produce complex molecules in multi-step reactions. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

The team led by Professor Wolfgang Schuhmann from the Center for Electrochemistry in Bochum and Professor Corina Andronescu from the University of Duisburg-Essen, together with the Australian team led by Professor Justin Gooding and Professor Richard Tilley, reported in the Journal of the American Chemical Society on 25 August 2019.

“Transferring the cascade reactions of the enzymes to catalytically active nanoparticles could be a decisive step in the design of catalysts,” says Wolfgang Schuhmann.

Ruhr U CO2 2 nanoparticles

Credit: CC0 Public Domain

Particle with two active centres

Enzymes have different active centres for cascade reactions, which are specialised in certain reaction steps. For example, a single enzyme can produce a complex product from a relatively simple starting material. In order to imitate this concept, the researchers synthesised a particle with a silver core surrounded by a porous layer of copper. The silver core serves as the first active centre, the copper layer as the second. Intermediate products formed at the silver core then react in the copper layer to form more complex molecules, which ultimately leave the particle.

In the present work, the German-Australian team showed that the electrochemical reduction of carbon dioxide can take place with the help of the nanozymes. Several reaction steps on the silver core and copper shell transform the starting material into ethanol or propanol.

“There are also other nanoparticles that can produce these products from CO2 without the cascade principle,” says Wolfgang Schuhmann. “However, they require considerably more energy.”

The researchers now want to further develop the concept of the cascade reaction in nanoparticles in order to be able to selectively produce even more valuable products such as ethylene or butanol.

Story Source:

Materials provided by Ruhr-University BochumNote: Content may be edited for style and length.


Journal Reference:

  1. Peter B. O’Mara, Patrick Wilde, Tania M. Benedetti, Corina Andronescu, Soshan Cheong, J. Justin Gooding, Richard D. Tilley, Wolfgang Schuhmann. Cascade Reactions in Nanozymes: Spatially Separated Active Sites inside Ag-Core–Porous-Cu-Shell Nanoparticles for Multistep Carbon Dioxide Reduction to Higher Organic MoleculesJournal of the American Chemical Society, 2019; 141 (36): 14093 DOI: 10.1021/jacs.9b07310

Irish Times – Plan for 80 Hydrogen Fuel Stations for Ireland by 2030


Irish Times FC image

Royal Dutch Shell’s first UK hydrogen refuelling station. Hydrogen’s big advantage, as a fuel, is that it’s quick and easy to use by a driver. File photograph: Chris Ratcliffe/Bloomberg via Getty Images

Currently only two hydrogen-fuelled Model cars available and neither is sold in Ireland

Plans for the introduction of a hydrogen fueling infrastructure for Ireland are accelerating, and a group representing those interested in using hydrogen as a fuel source is projecting that there will be 80 hydrogen filling stations by 2030.

Hydrogen Mobility Ireland is made up of industrial and governmental representatives, and includes, among others, BOC Gases, Bord Gáis EnergyToyota Ireland, CIÉ Group, Hyundai Ireland, and government departments from both north and south of the Border. The group wants to assess, and then push forward, ideas to bring hydrogen fuel for vehicles and public transport in Ireland.

The group’s initial report will be published on October 3rd, and one of its members, speaking to The Irish Times on background, confirmed that it will initially be aimed at “captive” fleets, whereby vehicles can be refuelled at a central depot. “It’s a central hub model, for now, rather than a distributed network. Our focus is on captive fleets, and Dublin Bus and CIÉ as a whole are both part of the group, and contributing to the discussions. Those early hydrogen fuelling stations would also be available for private users as well, to help encourage those who are interested in the technology.”

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Currently, only two hydrogen fuelled cars are available on the market – the Toyota Mirai and the Hyundai Nexo – and neither is sold in Ireland, for the simple reason that there is currently nowhere to refuel them.

Rancorous

The debate over the potential of hydrogen power for cars is often a rancorous one, with Tesla’s Elon Musk describing the power source as “dumb” and apparent internal disagreements within the VW Group over whether to press ahead with hydrogen vehicle development (Audi says yes, VW says no).

That debate is acknowledged by the group. Dr Richard Riley, a senior consultant at Element Energy, says: “Our view is that just like today, where there are multiple fuels for transport, the future will see both battery electric and hydrogen vehicles on the market filling different needs.

It is more efficient just to put that electricity straight into a battery vehicle. However, some vehicle operating profiles especially large trucks, refuse collection vehicles, some bus routes, rural and commuter train routes, ferries, police and ambulance fleets etc are not well suited to batteries as the battery range and recharging are not flexible enough to meet operators needs.

“Refuelling takes no longer than a conventional petrol or diesel car, and the usable range of a fuel cell vehicle is about the same as an ordinary car”

“Initial stations need a captive fleet to ensure the demand for hydrogen which helps to bring the cost of hydrogen down. However, right from the start we plan for some of the stations to be open to the public so that the investments made by industry and fleets benefits the wider community. We have explored a few different options for early fleets including taxis, buses and refuse collection vehicles. Some interest has been expressed across all these fleets.”

An advantage

Hydrogen’s big advantage, as a fuel, is that it’s quick and easy to use by a driver. Refuelling takes no longer than a conventional petrol or diesel car, and the usable range of a fuel cell vehicle is about the same as an ordinary car. Given current battery and charger designs, that’s an advantage that hydrogen is unlikely to surrender to electric cars any time soon. There’s also the fact that hydrogen is the most abundant element in the universe, and is relatively easily extracted from water.

“The only emission from a vehicle fuelled by hydrogen is water vapour, as the hydrogen combines in the fuel cell with oxygen, forming water, and generating an electrical current.”

That, however, is a rose-tinted view of hydrogen. While there have, in the past, been plans for vast solar-powered operations to extract hydrogen from seawater, much commercial hydrogen currently available is a by-product of fossil fuel extraction. On top of which, compressing it, transporting it and storing it all have significant energy consumption issues. The fuel cells themselves also suffer from some of the same issues surrounding batteries such as the use of rare-earth metals, which have to be expensively and messily mined.

Dr Riley says the hydrogen supply being proposed for Ireland comes is extracted using renewable electricity, a fact which might alleviate some of those concerns. Each of those 80 proposed hydrogen filling stations will require investment in the region of €1.5 – €2million.

The Government has made no commitments as yet on any incentives for such investments, but has, according to Dr Riley, “agreed that hydrogen shows great potential for Ireland and that the policies set out by the group to deliver hydrogen mobility are within the cost and policy limits that they committed to, to bring electric vehicles to market.”

“What we’re aiming to do is reach a point where other actors can start to make a decision to invest in hydrogen technology,” the group’s spokesperson said. “We need to reduce the unknowns, and raise the certainty level so that we can move from this phase through to implementation.

What we want to do is to have a highly visible, public strategy so that people can feel comfortable coming on board. This is not just an industry looking to feed itself – we’re drawing in a very broad spectrum of opinion from car makers, fleet operators, academics and policymakers.”

MIT: New approach suggests path to Emissions-Free Cement


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In a demonstration of the basic chemical reactions used in the new process, electrolysis takes place in neutral water. Dyes show how acid (pink) and base (purple) are produced at the positive and negative electrodes. A variation of this process can be used to convert calcium carbonate (CaCO3) into calcium hydroxide (Ca(OH)2), which can then be used to make Portland cement without producing any greenhouse gas emissions. Cement production currently causes 8 percent of global carbon emissions. Image: Felice Frankel

MIT researchers find a way to eliminate carbon emissions from cement production — a major global source of greenhouse gases.

It’s well known that the production of cement — the world’s leading construction material — is a major source of greenhouse gas emissions, accounting for about 8 percent of all such releases. If cement production were a country, it would be the world’s third-largest emitter.

A team of researchers at MIT has come up with a new way of manufacturing the material that could eliminate these emissions altogether, and could even make some other useful products in the process.

The findings are being reported today in the journal PNAS in a paper by Yet-Ming Chiang, the Kyocera Professor of Materials Science and Engineering at MIT, with postdoc Leah Ellis, graduate student Andres Badel, and others.

“About 1 kilogram of carbon dioxide is released for every kilogram of cement made today,” Chiang says. That adds up to 3 to 4 gigatons (billions of tons) of cement, and of carbon dioxide emissions, produced annually today, and that amount is projected to grow. The number of buildings worldwide is expected to double by 2060, which is equivalent to “building one new New York City every 30 days,” he says. And the commodity is now very cheap to produce: It costs only about 13 cents per kilogram, which he says makes it cheaper than bottled water.

So it’s a real challenge to find ways of reducing the material’s carbon emissions without making it too expensive. Chiang and his team have spent the last year searching for alternative approaches, and hit on the idea of using an electrochemical process to replace the current fossil-fuel-dependent system.

Ordinary Portland cement, the most widely used standard variety, is made by grinding up limestone and then cooking it with sand and clay at high heat, which is produced by burning coal. The process produces carbon dioxide in two different ways: from the burning of the coal, and from gases released from the limestone during the heating. Each of these produces roughly equal contributions to the total emissions. The new process would eliminate or drastically reduce both sources, Chiang says. Though they have demonstrated the basic electrochemical process in the lab, the process will require more work to scale up to industrial scale.

First of all, the new approach could eliminate the use of fossil fuels for the heating process, substituting electricity generated from clean, renewable sources. “In many geographies renewable electricity is the lowest-cost electricity we have today, and its cost is still dropping,” Chiang says. In addition, the new process produces the same cement product. The team realized that trying to gain acceptance for a new type of cement — something that many research groups have pursued in different ways — would be an uphill battle, considering how widely used the material is around the world and how reluctant builders can be to try new, relatively untested materials.

The new process centers on the use of an electrolyzer, something that many people have encountered as part of high school chemistry classes, where a battery is hooked up to two electrodes in a glass of water, producing bubbles of oxygen from one electrode and bubbles of hydrogen from the other as the electricity splits the water molecules into their constituent atoms. Importantly, the electrolyzer’s oxygen-evolving electrode produces acid, while the hydrogen-evolving electrode produces a base.

In the new process, the pulverized limestone is dissolved in the acid at one electrode and high-purity carbon dioxide is released, while calcium hydroxide, generally known as lime, precipitates out as a solid at the other. The calcium hydroxide can then be processed in another step to produce the cement, which is mostly calcium silicate.

The carbon dioxide, in the form of a pure, concentrated stream, can then be easily sequestered, harnessed to produce value-added products such as a liquid fuel to replace gasoline, or used for applications such as oil recovery or even in carbonated beverages and dry ice. The result is that no carbon dioxide is released to the environment from the entire process, Chiang says. By contrast, the carbon dioxide emitted from conventional cement plants is highly contaminated with nitrogen oxides, sulfur oxides, carbon monoxide and other material that make it impractical to “scrub” to make the carbon dioxide usable.

Calculations show that the hydrogen and oxygen also emitted in the process could be recombined, for example in a fuel cell, or burned to produce enough energy to fuel the whole rest of the process, Ellis says, producing nothing but water vapor.

In a demonstration of the basic chemical reactions used in the new process, electrolysis takes place in neutral water. Dyes show how acid (pink) and base (purple) are produced at the positive and negative electrodes. A variation of this process can be used to convert calcium carbonate (CaCO3) into calcium hydroxide (Ca(OH)2), which can then be used to make Portland cement without producing any greenhouse gas emissions. Cement production currently causes 8 percent of global carbon emissions.

In their laboratory demonstration, the team carried out the key electrochemical steps required, producing lime from the calcium carbonate, but on a small scale. The process looks a bit like shaking a snow-globe, as it produces a flurry of suspended white particles inside the glass container as the lime precipitates out of the solution.

While the technology is simple and could, in principle, be easily scaled up, a typical cement plant today produces about 700,000 tons of the material per year. “How do you penetrate an industry like that and get a foot in the door?” asks Ellis, the paper’s lead author. One approach, she says, is to try to replace just one part of the process at a time, rather than the whole system at once, and “in a stepwise fashion” gradually add other parts.

The initial proposed system the team came up with is “not because we necessarily think we have the exact strategy” for the best possible approach, Chiang says, “but to get people in the electrochemical sector to start thinking more about this,” and come up with new ideas. “It’s an important first step, but not yet a fully developed solution.”

The research was partly supported by the Skolkovo Institute of Science and Technology.

 

Monitoring Cancer at the Nano-Level – University of Waterloo


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Tapered nanowire array device design. Credit: Nature Nanotechnology (2019). DOI: 10.1038/s41565-019-0393-2

How a new quantum sensor could improve cancer treatment

The development of medical imaging and monitoring methods has profoundly impacted the diagnosis and treatment of cancer. These non-invasive techniques allow health care practitioners to look for cancer in the body and determine if treatment is working.

But current techniques have limitations; namely, tumours need to be a specific size to be visible. Being able to detect cancer cells, even before there are enough to form a tumour, is a challenge that researchers around the world are looking to solve.

The solution may lie in nanotechnology

Researchers at the University of Waterloo’s Institute for Quantum Computing (IQC) have developed a quantum sensor that is promising to outperform existing technologies in monitoring the success of cancer treatments.

Sensor image

 Artist’s rendering of the interaction of incident single photon pulses and a tapered semiconductor nanowire array photodetector.

 

“A sensor needs to be very efficient at detecting light,” explains principal investigator Michael Reimer, an IQC faculty member and professor in the Faculty of Engineering. “What’s unique about our sensor is that the light can be absorbed all the way, from UV to infrared. No commercially available device exists that can do that now.”

 

Current sensors reflect some of the light, and depending on the material, this reflection can add up to 30 percent of the light not being absorbed.

This next-generation quantum sensor designed in Reimer’s lab is very efficient and can detect light at the fundamental limit — a single photon — and refresh for the next one within nanoseconds. Researchers created an array of tapered nanowires that turn incoming photons into electric current that can be amplified and detected.

When applied to dose monitoring in cancer treatment, this enhanced ability to detect every photon means that a health practitioner could monitor the dose being given with incredible precision — ensuring enough is administered to kill the cancer cells, but not too much that it also kills healthy cells.

Moving quantum technology beyond the lab

Reimer published his findings in Nature Nanotechnology in March and is now working on a prototype to begin testing outside of his lab. Reimer’s goal is to commercialize the sensor in the next three to five years.

“I enjoy the fundamental research, but I’m also interested in bringing my research out of the lab and into the real world and making an impact to society,” says Reimer.

He is no stranger to bringing quantum technology to the marketplace. While completing his post doctorate at the Delft University of Technology in The Netherlands, Reimer was an integral part of the startup, Single Quantum, developing highly efficient single-photon detectors based on superconducting nanowires.

Reimer’s latest sensor has a wide range of applications beyond dose monitoring for cancer treatments. The technology also has the ability to significantly improve high-speed imaging from space and long-range, high-resolution 3D images.

“A broad range of industries and research fields will benefit from a quantum sensor with these capabilities,” said Reimer. “It impacts quantum communication to quantum lidar to biological applications. Anywhere you have photon-starved situations, you would want an efficient sensor.”

He is exploring all industries and opportunities to put this technology to use.

Breakthroughs come in unexpected places

After earning his undergraduate degree in physics at the University of Waterloo, Reimer moved to Germany to play professional hockey. While taking graduate courses at the Technical University of Munich, he met a professor of nanotechnology who sparked his interest in the field.

“I played hockey and science was my hobby,” says Reimer. “Science is still my hobby, and it’s amazing that it is now my job.” Reimer went on to complete his PhD at the University of Ottawa/National Research Council of Canada, and turned his attention to quantum light sources. Reimer is an internationally renowned expert in quantum light sources and sensors. The idea for the quantum sensor came from his initial research in quantum light sources.

“To get the light out from the quantum light source, we had to come up with a way that you don’t have reflections, so we made this tapered shape. We realized that if we can get the light out that way we could also do the reverse — that’s where the idea for the sensor came from.”

Reimer will be at the Waterloo Innovation Summit on October 1, to present his latest breakthrough and its potential impact on the health care sector. And while he works to bring the sensor to market, Reimer’s lab continues to push the boundaries of quantum photonics.

From discovering the path to perfect photon entanglement to developing novel solid-state quantum devices, Reimer’s research is advancing technologies that could disrupt a multitude of industries and research fields.

EIA projects nearly 50% increase in world energy usage by 2050, led by growth in Asia


 

global primary energy consumption by region

Source: U.S. Energy Information Administration, International Energy Outlook 2019 Reference case

 

In the International Energy Outlook 2019 (IEO2019) Reference case, released at 9:00 a.m. today, the U.S. Energy Information Administration (EIA) projects that world energy consumption will grow by nearly 50% between 2018 and 2050. Most of this growth comes from countries that are not in the Organization for Economic Cooperation and Development (OECD), and this growth is focused in regions where strong economic growth is driving demand, particularly in Asia.

EIA’s IEO2019 assesses long-term world energy markets for 16 regions of the world, divided according to OECD and non-OECD membership. Projections for the United States in IEO2019 are consistent with those released in the Annual Energy Outlook 2019.

global energy consumption by sector

Source: U.S. Energy Information Administration, International Energy Outlook 2019 Reference case

The industrial sector, which includes refining, mining, manufacturing, agriculture, and construction, accounts for the largest share of energy consumption of any end-use sector—more than half of end-use energy consumption throughout the projection period. World industrial sector energy use increases by more than 30% between 2018 and 2050 as consumption of goods increases. By 2050, global industrial energy consumption reaches about 315 quadrillion British thermal units (Btu).

Transportation energy consumption increases by nearly 40% between 2018 and 2050. This increase is largely driven by non-OECD countries, where transportation energy consumption increases nearly 80% between 2018 and 2050. Energy consumption for both personal travel and freight movement grows in these countries much more rapidly than in many OECD countries.

Energy consumed in the buildings sector, which includes residential and commercial structures, increases by 65% between 2018 and 2050, from 91 quadrillion to 139 quadrillion Btu. Rising income, urbanization, and increased access to electricity lead to rising demand for energy.

global net electricity generation

Source: U.S. Energy Information Administration, International Energy Outlook 2019 Reference case

The growth in end-use consumption results in electricity generation increasing 79% between 2018 and 2050. Electricity use grows in the residential sector as rising population and standards of living in non-OECD countries increase the demand for appliances and personal equipment. Electricity use also increases in the transportation sector as plug-in electric vehicles enter the fleet and electricity use for rail expands.

global primary energy consumption by energy source

Source: U.S. Energy Information Administration, International Energy Outlook 2019 Reference case

With the rapid growth of electricity generation, renewables—including solar, wind, and hydroelectric power—are the fastest-growing energy source between 2018 and 2050, surpassing petroleum and other liquids to become the most used energy source in the Reference case. Worldwide renewable energy consumption increases by 3.1% per year between 2018 and 2050, compared with 0.6% annual growth in petroleum and other liquids, 0.4% growth in coal, and 1.1% annual growth in natural gas consumption.

Global natural gas consumption increases more than 40% between 2018 and 2050, and total consumption reaches nearly 200 quadrillion Btu by 2050. In addition to the natural gas used in electricity generation, natural gas consumption increases in the industrial sector. Chemical and primary metals manufacturing, as well as oil and natural gas extraction, account for most of the growing industrial demand.

Global liquid fuels consumption increases more than 20% between 2018 and 2050, and total consumption reaches more than 240 quadrillion Btu in 2050. Demand in OECD countries remains relatively stable during the projection period, but non-OECD demand increases by about 45%.

Principal contributor: Ari Kahan

Fuel Cells to Receive Boost with pledge of 10M Vehicles


Toyota released the first mass-produced fuel cell  automobile, the Mirai, in 2014. But because of high costs, the technology has been slow to catch on.

Global ministers meeting will focus on ways to increase the technology’s use

An international conference on fuel cells that is scheduled to open here Wednesday is set to call for powering 10 million vehicles — including trains, planes and automobiles — with the environmentally friendly technology in 10 years, Nikkei has learned.

Currently, only around 10,000 vehicles around the world run on fuel cells, which use hydrogen to produce electricity without emitting Earth-warming carbon dioxide.

Japanese Industry Minister Isshu Sugawara will chair the second Hydrogen Energy Ministerial Meeting that will be attended by officials from the U.S., Europe and the Mideast. He has included the 10 million goal in his draft chairman’s statement, which also includes a goal to increase the number of hydrogen fueling stations to 10,000 in 10 years. There are now several hundred fueling stations globally.

The goal of 10 million vehicles is not a commitment, but is seen as an ambitious, common global target, the draft notes.

Toyota Motor introduced the first mass-produced fuel cell vehicle in 2014. Japan has considered the technology important even as battery-powered electric vehicles have been widely adopted overseas.

The chairman’s statement will also include a call for common standards and research agenda.

The meeting will endeavor to map out what a hydrogen supply chain might look like. Hydrogen is produced by the electrolysis of water, and once liquefied is easy to transport and store. The draft statement raises the possibility of cross-border trading and calls for determining international shipping routes and support for market trading.

One issue for fuel cell vehicles has been cost — Toyota’s fuel cell vehicle, the Mirai, has a sticker price of more than 7 million yen ($65,000), about 3 million more than a conventional hybrid. The Japanese government believes that by expanding the market, costs will fall, creating a positive feedback cycle.

In the U.S., there are around 25,000 fuel cell forklifts in operation. These types of industrial vehicles are included in the 10 million goal.

 

Re-Posted from Nikkei Asian Review

Platinum-graphene fuel cell catalysts show superior stability over bulk platinum – Georgia Institute of Tecnology


Seung Soon Jang, an associate professor, Faisal Alamgir, an associate professor, and Ji Il Choi, a postdoctoral researcher, all in Georgia Tech’s School of Materials Science and Engineering, examine a piece of platinum-graphene catalyst. Credit: Allison Carter

Films of platinum only two atoms thick supported by graphene could enable fuel cell catalysts with unprecedented catalytic activity and longevity, according to a study published recently by researchers at the Georgia Institute of Technology.

Platinum is one of the most commonly used catalysts for fuel cells because of how effectively it enables the oxidation reduction reaction at the center of the technology. But its high cost has spurred research efforts to find ways to use smaller amounts of it while maintaining the same .

“There’s always going to be an initial cost for producing a fuel cell with , and it’s important to keep that cost as low as possible,” said Faisal Alamgir, an associate professor in Georgia Tech’s School of Materials Science and Engineering. “But the real cost of a fuel cell system is calculated by how long that system lasts, and this is a question of durability.

“Recently there’s been a push to use catalytic systems without , but the problem is that there hasn’t been a system proposed so far that simultaneously matches the catalytic activity and the durability of platinum,” Alamgir said.

The Georgia Tech researchers tried a different strategy. In the study, which was published on September 18 in the journal Advanced Functional Materialsand supported by the National Science Foundation, they describe creating several systems that used atomically-thin  of platinum supported by a layer of graphene—effectively maximizing the total surface area of the platinum available for catalytic reactions and using a much smaller amount of the precious metal.

Most platinum-based catalytic systems use nanoparticles of the metal chemically bonded to a support surface, where surface atoms of the particles do most of the catalytic work, and the catalytic potential of the atoms beneath the surface is never utilized as fully as the surface atoms, if at all.

This graphic shows how the graphene layer in gray provides structure and stability to the two atomic layers of platinum above represented in blue. Credit: Ji Il Choi

Additionally, the researchers showed that the new platinum films that are at least two atoms thick outperformed nanoparticle platinum in the dissociation energy, which is a measure of the energy cost of dislodging a surface platinum atom. That measurement suggests those films could make potentially longer-lasting catalytic systems.

To prepare the atomically-thin films, the researchers used a process called electrochemical atomic layer deposition to grow platinum monolayers on a layer of graphene, creating samples that had one, two or three atomic layers of atoms. The researchers then tested the samples for dissociation energy and compared the results to the energy of a single atom of platinum on graphene as well as the energy from a common configurations of platinum nanoparticles used in catalysts.

“The fundamental question at the heart of this work was whether it was possible that a combination of metallic and  can render the platinum atoms in a platinum-graphene combination more stable than their counterparts in bulk platinum used commonly in catalysts that are supported by metallic bonding,” said Seung Soon Jang, an associate professor in the School of Materials Science and Engineering.

The researchers found that the bond between neighboring platinum atoms in the film essentially combines forces with the bond between the film and the graphene layer to provide reinforcement across the system. That was especially true in the platinum film that was two atoms thick.

“Typically metallic films below a certain thickness are not stable because the bonds between them are not directional, and they tend to roll over each other and conglomerate to form a particle,” Alamgir said. “But that’s not true with graphene, which is stable in a two-dimensional form, even one atom thick, because it has very strong covalent directional bonds between its neighboring . So this new catalytic system could leverage the directional bonding of the graphene to support an atomically-thin film of platinum.”

Future research will involve further testing of how the films behave in a catalytic environment. The researchers found in earlier research on graphene-platinum films that the material behaves similarly in catalytic reactions regardless of which side—graphene or platinum—is the exposed active surface.

“In this configuration, the graphene is not acting as a separate entity from the platinum,” Alamgir said. “They’re working together as one. So we believe that if you’re exposing the  side, you get the same catalytic activity and you could further protect the platinum, potentially further enhancing durability.”

More information: Ji Il Choi et al, Contiguous and Atomically Thin Pt Film with Supra‐Bulk Behavior Through Graphene‐Imposed Epitaxy, Advanced Functional Materials(2019).  DOI: 10.1002/adfm.201902274

Journal information: Advanced Functional Materials

Provided by Georgia Institute of Technology

Why Asia’s biggest economies are backing hydrogen fuel cell cars


 

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FILE PHOTO: An Air Liquide hydrogen station for hydrogen fuel cell cars is seen in Paris, France, October 13, 2016. REUTERS/Charles Platiau. 

China, Japan and South Korea have set ambitious targets to put millions of hydrogen-powered vehicles on their roads by the end of the next decade at a cost of billions of dollars.

But to date, hydrogen fuel cell vehicles (FCVs) have been upstaged by electric vehicles, which are increasingly becoming a mainstream option due to the success of Tesla Inc’s (TSLA.O) luxury cars as well as sales and production quotas set by China.

Critics argue FCVs may never amount to more than a niche technology. But proponents counter hydrogen is the cleanest energy source for autos available and that with time and more refueling infrastructure, it will gain acceptance.

AMBITIOUS TARGETS

China, far and away the world’s biggest auto market with some 28 million vehicles sold annually, is aiming for more than 1 million FCVs in service by 2030. That compares with just 1,500 or so now, most of which are buses.

fuel-cell-market4Read More: Fuel Cell Market by Type

Japan, a market of more than 5 million vehicles annually, wants to have 800,000 FCVs sold by that time from around 3,400 currently.

South Korea, which has a car market just one third the size of Japan, has set a target of 850,000 vehicles on the road by 2030. But as of end-2018, fewer than 900 have been sold.

 

WHY HYDROGEN?

 

Hydrogen’s proponents point to how clean it is as an energy source as water and heat are the only byproducts and how it can be made from a number of sources, including methane, coal, water, even garbage. Resource-poor Japan sees hydrogen as a way to greater energy security.

They also argue that driving ranges and refueling times for FCVs are comparable to gasoline cars, whereas EVs require hours to recharge and provide only a few hundred kilometers of range.

Many backers in China and Japan see FCVs as complementing EVs rather than replacing them. In general, hydrogen is seen as the more efficient choice for heavier vehicles that drive longer distances, hence the current emphasis on city buses.

THE MAIN PLAYERS

Only a handful of automakers have made fuel cell passenger cars commercially available.

Toyota Motor Corp (7203.T) launched the Mirai sedan at the end of 2014, but has sold fewer than 10,000 globally. Hyundai Motor Co (005380.KS) has offered the Nexo crossover since March last year and has sold just under 2,900 worldwide. It had sales of around 900 for its previous FCV model, the Tucson.

Buses are seeing more demand. Both Toyota and Hyundai have offerings and have begun selling fuel cell components to bus makers, particularly in China.

Several Chinese manufacturers have developed their own buses, notably state-owned SAIC Motor (600104.SS), the nation’s biggest automaker, and Geely Auto Group, which also owns the Volvo Cars and Lotus brands.

WHY HAVEN’T FUEL CELL CARS CAUGHT ON YET?

A lack of refueling stations, which are costly to build, is usually cited as the biggest obstacle to widespread adoption of FCVs. At the same time, the main reason cited for the lack of refueling infrastructure is that there are not enough FCVs to make them profitable.

Consumer worries about the risk of explosions are also a big hurdle and residents in Japan and South Korea have protested against the construction of hydrogen stations. This year, a hydrogen tank explosion in South Korea killed two people, which was followed by a blast at a Norway hydrogen station.

Then there’s the cost. Heavy subsidies are needed to bring prices down to levels of gasoline-powered cars. Toyota’s Mirai costs consumers just over 5 million yen ($46,200) after subsidies of 2.25 million yen. That’s still about 50% more than a Camry.

Automakers contend that once sales volumes increase, economies of scale will make subsidies unnecessary.

 

HOW FUEL CELLS WORK

(GRAPHIC: How fuel cell vehicles work: here)

Reuters Graphic

 

Reuters: Reporting by Kevin Buckland in Tokyo; Additional reporting by Yilei Sun in Beijing and Hyunjoo Jin in Seoul; Editing by Edwina Gibbs

 

 

DNA ‘Origami’ takes Flight in Emerging Field of Nano Machines – “(a) … tool may eventually be used to fine tune immunotherapies for individual cancer patients”


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DNA mechanotechnology expands the opportunities for research involving biomedicine and materials sciences, says Khalid Salaita, right, professor of chemistry at Emory University and co-author of the article, along with Aaron Blanchard, left, a graduate student in the Salaita Lab. Credit: Emory University

Just as the steam engine set the stage for the Industrial Revolution, and micro transistors sparked the digital age, nanoscale devices made from DNA are opening up a new era in bio-medical research and materials science.

The journal Science describes the emerging uses of DNA  in a “Perspective” article by Khalid Salaita, a professor of chemistry at Emory University, and Aaron Blanchard, a graduate student in the Wallace H. Coulter Department of Biomedical Engineering, a joint program of Georgia Institute of Technology and Emory.

The article heralds a new field, which Blanchard dubbed “DNA mechanotechnology,” to engineer DNA machines that generate, transmit and sense  at the nanoscale.

“For a long time,” Salaita says, “scientists have been good at making micro devices, hundreds of times smaller than the width of a human hair. It’s been more challenging to make functional nano devices, thousands of times smaller than that. But using DNA as the component parts is making it possible to build extremely elaborate nano devices because the DNA parts self-assemble.”

DNA, or deoxyribonucleic acid, stores and transmits genetic information as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T). The DNA bases have a natural affinity to pair up with each other—A with T and C with G. Synthetic strands of DNA can be combined with natural DNA strands from bacteriophages. By moving around the sequence of letters on the strands, researchers can get the DNA strands to bind together in ways that create different shapes. The stiffness of DNA strands can also easily be adjusted, so they remain straight as a piece of dry spaghetti or bend and coil like boiled spaghetti.

The idea of using DNA as a construction material goes back to the 1980s, when biochemist Nadrian Seeman pioneered DNA nanotechnology. This field uses strands DNA to make functional devices at the nanoscale. The ability to make these precise, three-dimensional structures began as a novelty, nicknamed DNA origami, resulting in objects such as a microscopic map of the world and, more recently, the tiniest-ever game of tic-tac-toe, played on a DNA board.

Work on novelty objects continues to provide new insights into the mechanical properties of DNA. These insights are driving the ability to make DNA machines that generate, transmit and sense mechanical forces.

“If you put together these three main components of mechanical devices, you begin to get hammers and cogs and wheels and you can start building nano machines,” Salaita says. “DNA mechanotechnology expands the opportunities for research involving biomedicine and materials science. It’s like discovering a new continent and opening up fresh territory to explore.”

Potential uses for such devices include drug delivery devices in the form of nano capsules that open up when they reach a target site, nano computers and nano robots working on nanoscale assembly lines.

The use of DNA self-assembly by the genomics industry, for biomedical research and diagnostics, is further propelling DNA mechanotechnology, making DNA synthesis inexpensive and readily available. “Potentially anyone can dream up a nano-machine design and make it a reality,” Salaita says.

He gives the example of creating a pair of nano scissors. “You know that you need two rigid rods and that they need to be linked by a pivot mechanism,” he says. “By tinkering with some open-source software, you can create this design and then go onto a computer and place an order to custom synthesize your design. You’ll receive your order in a tube. You simply put the tube contents into a solution, let your device self-assemble, and then use a microscope to see if it works the way you thought that it would.”

Salaita’s lab is one of only about 100 around the world working at the forefront of DNA mechanotechnology. He and Blanchard developed the world’s strongest synthetic DNA-based motor, which was recently reported in Nano Letters.

A key focus of Salaita’s research is mapping and measuring how cells push and pull to learn more about the mechanical forces involved in the human immune system.

Salaita developed the first DNA force gauges for cells, providing the first detailed view of the mechanical forces that one molecule applies to another molecule across the entire surface of a living cell. Mapping such forces may help to diagnose and treat diseases related to cellular mechanics. Cancer cells, for instance, move differently from normal cells, and it is unclear whether that difference is a cause or an effect of the disease.

In 2016, Salaita used these DNA force gauges to provide the first direct evidence for the mechanical forces of T cells, the security guards of the immune system. His lab showed how T cells use a kind of mechanical “handshake” or tug to test whether a cell they encounter is a friend or foe. These mechanical tugs are central to a T cell’s decision for whether to mount an immune response.

“Your blood contains millions of different types of T cells, and each T cell is evolved to detect a certain pathogen or foreign agent,” Salaita explains. “T cells are constantly sampling cells throughout your body using these mechanical tugs. They bind and pull on proteins on a cell’s surface and, if the bond is strong, that’s a signal that the T cell has found a foreign agent.”

Salaita’s lab built on this discovery in a paper recently published in the Proceedings of the National Academy of Sciences (PNAS). Work led by Emory chemistry graduate student Rong Ma refined the sensitivity of the DNA force gauges. Not only can they detect these mechanical tugs at a force so slight that it is nearly one-billionth the weight of a paperclip, they can also capture evidence of tugs as brief as the blink of an eye.

The research provides an unprecedented look at the mechanical forces involved in the immune system. “We showed that, in addition to being evolved to detect certain foreign agents, T cells will also apply very brief mechanical tugs to foreign agents that are a near match,” Salaita says. “The frequency and duration of the tug depends on how closely the foreign agent is matched to the T cell receptor.”

The result provides a tool to predict how strong of an immune response a T cell will mount. “We hope this tool may eventually be used to fine tune immunotherapies for individual cancer patients,” Salaita says. “It could potentially help engineer T  to go after particular .”