A new method of extracting hydrogen from water more efficiently could help underpin the capture of renewable energy in the form of sustainable fuel, scientists say.
In a new paper, published today in the journalNature Communications, researchers from universities in the UK, Portugal, Germany and Hungary describe how pulsingelectric currentthrough a layered catalyst has allowed them to almost double the amount ofhydrogenproduced per millivolt of electricity used during the process.
Electrolysis, a process which is likely familiar to anyone who studied chemistry athigh school, uses electric current to split the bonds between the hydrogen and oxygen atoms of water, releasing hydrogen and oxygen gas.
If the electric current for the process of electrolysis is generated through renewable means such as wind orsolar power, the entire process releases no additional carbon into the atmosphere, making no contributions to climate change. Hydrogen gas can then be used as a zero-emission fuel source in some forms of transport such as buses and cars or for heating homes.
The team’s research focused on finding a more efficient way to produce hydrogen through the electrocatalytic water splitting reaction. They discovered that electrodes covered with a molybedenum telluride catalyst showed an increase in the amount of hydrogen gas produced during the electrolysis when a specific pattern of high-current pulses was applied.
By optimising the pulses of current through the acidic electrolyte, they could reduce the amount of energy needed to make a given amount of hydrogen by nearly 50%.
Dr. Alexey Ganin, of the University of Glasgow’s School of Chemistry, directed the research team. Dr. Ganin said: “Currently the UK meets about a third of its energy production needs through renewable sources, and in Scotland that figure is about 80%.
“Experts predict that we’ll soon reach a point where we’ll be producing more renewable electricity than our consumption demands. However, as it currently stands the excess of generated energy must be used as it’s produced or else it goes to waste. It’s vital that we develop a robust suite of methods to store theenergyfor later use.
“Batteries are one way to do that, but hydrogen is a very promising alternative. Our research provides an important new insight into producing hydrogen from electrolysis more effectively and more economically, and we’re keen to pursue this promising avenue of investigation.”
Since the level of catalytic enhancement is controlled by electric currents, recent advances in machine learning could be used to fine-tune the right sequence of applied currents to achieve the maximum output.
The next stage for the team is the development of an artificial intelligence protocol to replace human input in the search for the most effective electronic structures use in similar catalytic processes.
The paper, titled “The rapid electrochemical activation of MoTe2 for the hydrogen evolution reaction,” is published in Nature Communications
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.
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 samecatalytic activity.
“There’s always going to be an initial cost for producing a fuel cell withplatinum catalysts, 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 withoutplatinum, 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 journalAdvanced Functional Materialsand supported by the National Science Foundation, they describe creating several systems that used atomically-thinfilmsof 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.
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 andcovalent bondingcan 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 neighboringatoms. 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 thegrapheneside, 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
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.
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.
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.
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.
Honda Motor Co Ltd’s (7267.T) Clarity Fuel Cell is available for lease, while Daimler AG’s GLC F-CELL has been delivered to a handful of corporate and public sector clients.
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.
As renewable sources such as wind and solar are quickly changing the energy landscape, scientists are looking for ways to better store energy for when it’s needed. Fuel cells, which convert chemical energy into electrical power, are one possible solution for long-term energy storage, and could someday be used to power trucks and cars without burning fuel. But before fuel cells can be widely used, chemists and engineers need to find ways to make this technology more cost-effective and stable.
A new study from the lab of Penn Integrates Knowledge Professor Christopher Murray, led by graduate student Jennifer Lee, shows how custom-designed nanomaterials can be used to address these challenges. In ACS Applied Materials & Interfaces, researchers show how a fuel cell can be built from cheaper, more widely available metals using an atomic-level design that also gives the material long-term stability. Former post-doc Davit Jishkariani and former students Yingrui Zhao and Stan Najmr, current student Daniel Rosen, and professors James Kikkawa and Eric Stach, also contributed to this work.
The chemical reaction that powers a fuel cell relies on two electrodes, a negative anode and a positive cathode, separated by an electrolyte, a substance that allows the ions to move. When fuel enters the anode, a catalyst separates molecules into protons and electrons, with the latter traveling toward the cathode and creating an electric current.
Catalysts are typically made of precious metals, like platinum, but because the chemical reactions only occur on the surface of the material, any atoms that are not presented on the surface of the material are wasted. It’s also important for catalysts to be stable for months and years because fuel cells are very difficult to replace.
Chemists can address these two problems by designing custom nanomaterials that have platinum at the surface while using more common metals, such as cobalt, in the bulk to provide stability. The Murray group excels at creating well-controlled nanomaterials, known as nanocrystals, in which they can control the size, shape, and composition of any composite nanomaterial.
In this study, Lee focused on the catalyst in the cathode of a specific type of fuel cell known as a proton exchange membrane fuel cell. “The cathode is more of a problem, because the materials are either platinum or platinum-based, which are expensive and have slower reaction rates,” she says. “Designing the catalyst for the cathode is the main focus of designing a good fuel cell.”
The challenge, explains Jishkariani, was in creating a cathode in which platinum and cobalt atoms would form into a stable structure. “We know cobalt and platinum mixes well; however, if you make alloys of these two, you have added atoms of platinum and cobalt in a random order,” he says. Adding more cobalt in a random order causes it to leach out into the electrode, meaning that the fuel cell will only function for a short time.
To solve this problem, researchers designed a catalyst made of layered platinum and cobalt known as an intermetallic phase. By controlling exactly where each atom sat in the catalyst and locking the structure in place, the cathode catalyst was able to work for longer periods than when the atoms were arranged randomly. As an additional unexpected finding, the researchers found that adding more cobalt to the system led to greater efficiency, with a 1-to-1 ratio of platinum to cobalt, better than many other structures with a wide range of platinum-to-cobalt ratios.
The next step will be to test and evaluate the intermetallic material in fuel cell assemblies to make direct comparisons to commercially-available systems. The Murray group will also be working on new ways to create the intermetallic structure without high temperatures and seeing if adding additional atoms improve the catalyst’s performance.
This work required high-resolution microscopic imaging, work that Lee previously did at Brookhaven National Lab but, thanks to recent acquisitions, can now be done at Penn in the Singh Center for Nanotechnology. “Many of the high-end experiments that we would have had to travel to around the country, sometimes around the world, we can now do much closer to home,” says Murray. “The advances that we’ve brought in electron microscopy and X-ray scattering are a fantastic addition for people that work on energy conversion and catalytic studies.”
Lee also experienced first-hand how chemistry research directly connects to real world challenges. She recently presented this work at the International Precious Metals Institute conference and says that meeting members of the precious-metals community was enlightening. “There are companies looking at fuel cell technology and talking about the newest design of the fuel cell cars,” she says. “You get to interact with people that think of your project from different perspectives.”
Murray sees this fundamental research as a starting point towards commercial implementation and real world application, emphasizing that future progress relies on the forward-looking research that’s happening now. “Thinking about a world where we’ve displaced a lot of the traditional fossil fuel-based inputs, if we can figure out this interconversion of electrical and chemical energy, that will address a couple of very important problems simultaneously.”
*** This article appeared in TESLARATI and was re-posted in Fully Charged. We have Followed and Written a LOT about the ‘Coming EV Revolution’, about Advances in Charging Stations and Battery Technology. Most recently we posted an article ‘What If Green Energy Isn’t the Future?’
So maybe … just maybe, ‘Green Energy’ might NOT be able to meet the current Projected Carbon Fuel Replacement Schedule …. However, could the EV/ Hydrogen Fuel Cell Revolution replace forever the Internal Combustion Engine (ICE)? (Hint: We Think So!)
Let Us Know What YOU think! Leave us your thoughts and comments. (below)
Headed by vehicles like the Tesla Model 3, the electric car revolution is showing no signs of stopping. The auto landscape today is very different from what it was years ago. Before, only Tesla and a few automakers were pushing electric cars, and the Model S was proving to the industry that EVs could be objectively better than internal combustion vehicles. Today, practically every automaker has plans to release electric cars. EV startup Bollinger Motors CEO Robert Bollinger summed it up best: “If you want to start a (car company) now, it has to be electric.”
CATALYSTS FOR A TRANSITION
A critical difference between then and now is that veteran automakers today are coming up with decent electric vehicles. No longer were EVs glorified golf carts and compliance cars; today’s electric vehicles are just as attractive, sleek, and powerful than their internal combustion peers. The auto industry has warmed up to electric vehicles as well. The Jaguar I-PACE has been collecting awards left and right since its release, and more recently, the Kia Niro EV was dubbed by Popular Mechanics as the recipient of its Car of the Year award.
A survey by CarGurus earlier this year revealed that 34% of car buyers are open to purchasing an electric car within the next ten years. A survey among young people in the UK last year revealed even more encouraging results, with 50% of respondents stating that they want electric cars. Amidst the disruption being brought about by the Tesla Model 3, which has all but dominated EV sales since production ramped last year, experienced automakers have responded in kind. Volkswagen recently debuted the ID.3, Audi has the e-tron, Hyundai has the Kona EV, and Mercedes-Benz has the EQC. Even Porsche, a low-volume car manufacturer, is attracting the high-end legacy market with the Taycan.
At this point, it appears that Tesla’s mission is going well underway. With the market now open to the idea of electric vehicles, there is an excellent chance that EV adoption will only increase from this point on.
BIG OIL FEELS A CHANGE IN THE WIND
Passenger cars are the No.1 source of demand for oil, and with the potential emergence of a transportation industry whose life and death does not rely on a gas pump, Big Oil could soon find itself on the defensive. Depending on how quickly the auto industry could shift entirely to sustainable transportation and how seriously governments handle issues like climate change, “peak oil” could happen a couple of decades or a few years from now. This could adversely affect investors in the oil industry, who might be at risk of losing their investments if peak oil happens faster than expected. JJ Kinahan, chief market strategist at TD Ameritrade, described this potential scenario in a statement to CNN. “Look at what happened to the coal industry. You have to keep that in the back of your mind and be vigilant. It can turn very, very quickly,” the strategist said.
Paul Sankey of Mizuho Securities previously mentioned that a “Tesla Effect” is starting to be felt in the oil markets. According to the analyst, the Tesla Effect is an increasingly prevalent concept today which states that while the 20th century was driven by oil, the 21st century will be driven by electricity. This, together with the growing movements against climate change today, does not bode well for the oil industry. Adam White, an equity strategist at SunTrust Advisory, stated that investors might not be looking at the oil market with optimism anymore. “A lot of damage has already been done. People are jaded towards the industry,” he said.
An analysis from Barclays points to the world’s reliance on oil peaking somewhere between 2030 and 2035, provided that countries keep to their low-carbon goals. The investment bank also noted that peak oil could happen as early as 2025 if more aggressive climate change initiatives are adopted on a wider scale. This all but makes investments in oil stocks very risky in the 2020s, and this risk gets amplified if electric vehicles become more mainstream. Sverre Alvik of research firm DNV GL described this concern. “By 2030, oil shareholders will feel the impact. Electric vehicles are likely to cause light vehicle oil demand to plunge by nearly 50% by 2040,” Alvik said.
Some of today’s prolific oil producers appear to be making the necessary preparations for peak oil’s inevitable decline. Amidst pressures from shareholders, BP, Royal Dutch Shell, and Total have expanded their operations into solar, wind, and electric charging, seemingly as a means to future-proof themselves. On the flipside, there are also big oil players that are ramping their activities. Earlier this month, financial titan Warren Buffet, who recently expressed his skepticism towards Elon Musk’s plan of introducing an insurance service for Tesla’s electric cars, committed $10 billion to Occidental Petroleum, one of the largest oil and gas exploration companies in the United States.
A POINT OF NO RETURN
The auto industry is now at a point where a real transition towards electrification is happening. Tesla’s efforts over the years, from the original Roadster to the Model 3, have played a huge part in this transition. Tesla, as well as its CEO, Elon Musk, have awakened the public’s eye about the viability of electric cars, while showing the auto industry that there is a demand for good, well-designed EVs. Nevertheless, Tesla still has a long journey ahead of it, as the company ramps its activities in the energy storage sector. If Tesla Energy mobilizes and becomes as disruptive as the company’s electric car division, it would deal yet another blow to the oil industry.
At this point, it is pertinent for veteran automakers that have released their own electric cars to ensure that they do not stop. Legacy car makers had long talked the talk when it came to electric vehicles, but today, it is time to walk the walk. German automaker Volkswagen could be a big player in this transition, as hinted at by the reception of its all-electric car, the ID.3. The ID.3 launch was successful, with Volkswagen getting 10,000 preorders for the vehicle in just 24 hours. The German carmaker should see this as writing on the wall: the demand for EVs is there.
The Volkswagen ID.3 is not as quick or sleek as a Tesla Model 3, nor does it last as long on the road between charges. But considering its price point and its badge, it does not have to be. Volkswagen states that the ID.3 will be priced below 40,000 euros ($45,000) in Germany, which should make it attainable for car buyers in the country. If done right, the ID.3 could be the second coming of the Beetle, ultimately becoming a car that redeems the company from the stigma of the Dieselgate scandal. Thus, it would be a great shame if Volkswagen drops the ball on the ID.3.
Tesla will likely remain a divisive company for years to come; Elon Musk, even more so. Nevertheless, Tesla and what it stands for is slowly becoming an idea, one that connotes hope for something better and cleaner for the future. And if history’s victories and tragedies are any indication, once something becomes an idea, an intangible concept, it becomes impossible to kill.
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Mobility Disruption | Tony Seba
Tony Seba, Silicon Valley entrepreneur, Author and Thought Leader, Lecturer at Stanford University, Keynote The reinvention and connection between infrastructure and mobility will fundamentally disrupt the clean transport model.
While EVs have come a long way — evenFord is making electric trucks— they’re still a far cry from perfect. One of the biggest complaints is that the batteries need to be plugged in and recharged, and even when they’re charged, they have a limited range.Fuel cell electric vehiclesoffer an alternative.
Their “battery” — actually a hydrogen/oxygen fuel cell — can be replenished with hydrogen gas. The biggest problem to-date has been thatproducing hydrogenisn’t an environmentally friendly process. We would also need the infrastructure to refuel with hydrogen. But, new technology from UMass Lowell could remove those barriers.
Researchers there have created a way to produce hydrogen on demand using water, carbon dioxide and cobalt. Theoretically, that would go directly into a fuel cell, where it would mix with oxygen to generate electricity and water. The electricity would then power the EV’s motor, rechargeable battery and headlights.
According to UMass Lowell, the hydrogen produced is 95 percent pure, and vehicles would not need to be refueled at a filling station. Instead, owners would replace canisters of the cobalt metal which would fuel the hydrogen generator.
Because the technology can produce hydrogen at low temperatures and pressures and because excess isn’t stored in the vehicle, it minimizes the risk of fire or explosion. While this isn’t a practical application yet, it could help make FCEVs a viable option.
In a statement from UMass Lowell’s Chemistry Department Chairman Professor David Ryan below said that vehicles would not be refueled at a fueling station.
The system that we have devised would not require the vehicle to be refueled at a hydrogen filling station.
Our technology would use canisters of the cobalt metal as the fuel to operate the hydrogen generator.
The canisters would be swapped out when expended. It’s really too early to tell, but the goal is typically to be able to travel up to 350 to 400 miles for most vehicles before “refueling.”
A new method of increasing the reactivity of ultrathin nanosheets, just a few atoms thick, can someday make fuel cells for hydrogen cars cheaper, finds a new Johns Hopkins study.
A platinum-like metal only five atomic layers thick is “just right” for optimizing the performance of a fuel cell electrode. Credit: Johns Hopkins University image/Lei Wang
A report of the findings, to be published Feb. 22 in Science, offers promise towards faster, cheaper production of electrical power using fuel cells, but also of bulk chemicals and materials such as hydrogen.
“Every material experiences surface strain due to the breakdown of the material’s crystal symmetry at the atomic level. We discovered a way to make these crystals ultrathin, thereby decreasing the distance between atoms and increasing the material’s reactivity,” says Chao Wang, an assistant professor of chemical and biomolecular engineering at The Johns Hopkins University, and one of the study’s corresponding authors.
Strain is, in short, the deformation of any material. For example, when a piece of paper is bent, it is effectively disrupted at the smallest, atomic level; the intricate lattices that hold the paper together are forever changed.
In this study, Wang and colleagues manipulated the strain effect, or distance between atoms, causing the material to change dramatically. By making those lattices incredibly thin, roughly a million times thinner than a strand of human hair, the material becomes much easier to manipulate just like how one piece of paper is easier to bend than a thicker stack of paper.
“We’re essentially using force to tune the properties of thin metal sheets that make up electrocatalysts, which are part of the electrodes of fuel cells,” says Jeffrey Greeley, professor of chemical engineering at Purdue and another one of the paper’s corresponding authors. “The ultimate goal is to test this method on a variety of metals.”
“By tuning the materials‘ thinness, we were able to create more strain, which changes the material’s properties, including how molecules are held together. This means you have more freedom to accelerate the reaction you want on the material’s surface,” explains Wang.
One example of how optimizing reactions can be useful in application is increasing the activity of catalysts used for fuel cell cars. While fuel cells represent a promising technology toward emission-free electrical vehicles, the challenge lies in the expense associated with the precious metal catalysts such as platinum and palladium, limiting its viability to the vast majority of consumers. A more active catalyst for the fuel cells can reduce cost and clear the way for widespread adoption of green, renewable energy.
Wang and colleagues estimate that their new method can increase catalyst activity by 10 to 20 times, using 90 percent less of precious metals than what is currently required to power a fuel cell.
“We hope that our findings can someday aid in the production of cheaper, more efficient fuel cells to make environmentally-friendly cars more accessible for everybody,” says Wang.
Scientists have used a Nobel-prize winning chemistry technique on a mixture of metals to potentially reduce the cost of fuel cells used in electric cars and reduce harmful emissions from conventional vehicles.
The researchers have translated a biological technique, which won the 2017 Nobel Chemistry Prize, to reveal atomic scale chemistry in metal nanoparticles.These materials are one of the most effective catalysts for energy converting systems such as fuel cells. It is the first time this technique has been for this kind of research.
The particles have a complex star-shaped geometry and this new work shows that the edges and corners can have different chemistries which can now be tuned to reduce the cost of batteries and catalytic convertors.
The 2017 Nobel Prize in Chemistry was awarded to Joachim Frank, Richard Henderson and Jacques Dubochet for their role in pioneering the technique of single particle reconstruction. This electron microscopy technique has revealed the structures of a huge number of viruses and proteins but is not usually used for metals.
Now, a team at the University of Manchester, in collaboration with researchers at the University of Oxford and Macquarie University, have built upon the Nobel Prize winning technique to produce three dimensional elemental maps of metallic nanoparticles consisting of just a few thousand atoms.
Published in the journal Nano Letters, their research demonstrates that it is possible to map different elements at the nanometre scale in three dimensions, circumventing damage to the particles being studied.
Metal nanoparticles are the primary component in many catalysts, such as those used to convert toxic gases in car exhausts. Their effectiveness is highly dependent on their structure and chemistry, but because of their incredibly small structure, electron microscopes are required in order to provide image them. However, most imaging is limited to 2-D projections.
“We have been investigating the use of tomography in the electron microscope to map elemental distributions in three dimensions for some time,” said Professor Sarah Haigh, from the School of Materials, University of Manchester. “We usually rotate the particle and take images from all directions, like a CT scan in a hospital, but these particles were damaging too quickly to enable a 3-D image to be built up. Biologists use a different approach for 3-D imaging and we decided to explore whether this could be used together with spectroscopic techniques to map the different elements inside the nanoparticles.”
“Like ‘single particle reconstruction’ the technique works by imaging many particles and assuming that they are all identical in structure, but arranged at different orientations relative to the electron beam. The images are then fed in to a computer algorithm which outputs a three dimensional reconstruction.”
In the present study the new 3-D chemical imaging method has been used to investigate platinum-nickel (Pt-Ni) metal nanoparticles.
Lead author, Yi-Chi Wang, also from the School of Materials, added: “Platinum based nanoparticles are one of the most effective and widely used catalytic materials in applications such as fuel cells and batteries. Our new insights about the 3-D local chemical distribution could help researchers to design better catalysts that are low-cost and high-efficiency.”
“We are aiming to automate our 3-D chemical reconstruction workflow in the future”, added author Dr. Thomas Slater.”We hope it can provide a fast and reliable method of imaging nanoparticle populations which is urgently needed to speed up optimisation of nanoparticle synthesis for wide ranging applications including biomedical sensing, light emitting diodes, and solar cells.”
More information: Yi-Chi Wang et al. Imaging Three-Dimensional Elemental Inhomogeneity in Pt–Ni Nanoparticles Using Spectroscopic Single Particle Reconstruction, Nano Letters (2019). DOI: 10.1021/acs.nanolett.8b03768