An Alternative to Kevlar – MIT and Caltech Create Nanotech Carbon Materials – Can withstand supersonic microparticle impacts
New Nanoscale Material Harvests Hydrogen Fuel From the Sea – University of Central Florida
Engineers Develop a Simple Way to Desalinate Water Using Solar Energy – Reduced Costs + 4X Production Volume
Hydrogen Powered Fuel Cell EV’s? Or Battery Powered EV’s? Toyota is Placing a Bet on the Green Future
While Toyota has seen success far and wide as an early pioneer of hybrid cars, it’s had much less luck with another technology it has invested heavily in: hydrogen-powered fuel cell EVs.
While the rest of the electric car market is going heavily battery-powered, Toyota is still banking on hydrogen power in many ways—even as competitors like Honda and BMW have seemingly dialed down their hydrogen ambitions. Now we know that Toyota’s conservative battery EV strategy and its big bet on hydrogen are closely related issues.
A recent report from the New York Times shows that the company’s hydrogen play has become further reaching than just internal development; it has also become political.
According to the report, a Toyota executive has been traveling to Washington on behalf of the automaker and has taken steps to slow the entire industry’s adoption of electric vehicles. Chris Reynolds, a high-ranking senior executive for Toyota, reportedly has held closed-door meetings with congressional staff members.
At least four people familiar with the matter told the New York Times that Reynolds argued against an aggressive rollout of fully electric vehicles, instead urging for a focus on hybrids (like the Prius) and other alternatively-fueled vehicles, like hydrogen-powered fuel-cell EVs.
This all comes at a time when multiple automakers are planning to go fully or mostly battery electric in the years to come, often driven by tightening emissions rules in China and Europe. Toyota, on the other hand, feels incredibly late to the EV game.
Despite Toyota’s recent ambitious plans to launch 15 fully electric cars by 2025, it has only shown the world a concept of its upcoming bZ4X while other manufacturers like Audi, Ford, Hyundai, Jaguar, Porsche, Volvo, and Volkswagen all have at least one BEV for sale today.
So if Toyota can persuade lawmakers of the importance of hybrids over EVs and successfully stymie funding for EV-related infrastructure and incentives, it could give the automaker more time to separate from its crutch on hybrids and catch up to other manufacturers.
The potential impact of lobbying against BEVs can be seen in the recently proposed infrastructure spending bill, which cuts the government funding for expanding the EV charging infrastructure in half of what was anticipated by President Joe Biden’s staffers to deploy 500,000 EV charging stations nationwide.
In addition to doing a potential disservice to American EV adopters, these actions could potentially impede the already full-speed efforts by other automakers pushing towards aggressive EV rollouts.
It is worth noting, Reynolds was recently named board chair for the Alliance for Automotive Innovation. The alliance is a lobbying organization that represents the interests of many automakers and OEM suppliers, many of which aren’t as heavily invested in hydrogen power or hybrids as Toyota.
What if your electric vehicle could be refueled in less than 5 minutes? No plug, no outlet required. The range anxiety that’s stymied sales of EVs? Forget about it.
Three EVs can meet these demands and allay concerns about owning an emissions-free vehicle.
There’s just one drawback. You can only find them in California.
Welcome to the world of hydrogen fuel cell electric vehicles (FCEVs). A tiny market that includes Toyota’s Mirai, Hyundai’s Nexo and Honda Motor’s Clarity Fuel Cell, these “plug-less” EVs are the alternative to their battery electric cousins. Drivers can refuel FCEVs at a traditional gasoline station in less than 5 minutes.
The 2021 Mirai gets an EPA estimated 402 miles of range on the XLE trim with the Nexo close behind at 380 miles. Neither cold weather nor heated seats deplete the range, another added bonus.
“Hydrogen fuel cell vehicles are superior driving machines compared to traditional vehicles,” Jackie Birdsall, senior engineer on Toyota’s fuel cell team, told ABC News.
Toyota sees tremendous upside in fuel cell technology, which it has been perfecting for 25 years. More than 6,500 Mirais have been sold or leased in California since its launch in 2015. The second generation Mirai, on sale next month in San Francisco and Los Angeles, can store more hydrogen than its predecessor, giving the sleek sedan a 30% increase in range.
Toyota Motor
“When people hear electric they only think battery electric,” Birdsall said. “The BEV [battery electric vehicle] market is pretty saturated. If we want to have sustainability and longevity we need to be diverse.”
Toyota Motor
FCEVs work like this: Electricity is generated from an onboard supply of hydrogen. That electricity powers the electric motor. When hydrogen gas is converted into electricity, water and heat are released. An FCEV stores the hydrogen in high-pressure tanks (the Mirai, for example, has three). Non-toxic, compressed hydrogen gas flows into the tank when refueling.
“If we can build the stations, we can build the cars,” Keith Malone of the California Fuel Cell Partnership, an industry-government collaboration founded in 1999 to expand the domestic FCEV market, told ABC News. “These vehicles have met all the same safety standards globally. The tanks have undergone armor piercing bullet tests. There are no dangers.”
Malone, a longtime advocate of hydrogen-powered vehicles, did concede that the nascent industry has more hurdles to clear before it’s widely accepted.
“We are an early market and these cars are not cheap for lease or sale,” he said. “Most stations are concentrated in urban areas in California. But we’ve seen a lot of progress.
The real challenge is rolling out the fueling network. But the vehicles are here. They’re good, people love them.”
Hyundai
J.R. DeShazo, director of the Luskin Center for Innovation at UCLA, remembers when Arnold Schwarzenegger, the former governor, vowed to revamp California’s highways as “Hydrogen Highways” in 2004. The infrastructure to support hydrogen fuel for transportation never materialized. DeShazo doubts it ever will.
“If there were stations everywhere, hydrogen would be an obvious solution,” he told ABC News. “Refueling stations are really expensive and require significant economies of scale to be cost effective and compete with gasoline and electricity.”
Hyundai
Betting on batteries
There are currently 42 hydrogen fueling stations in California though not all are online. The average price of hydrogen is $16 a kilogram versus $3.18 for a gallon of gasoline in the state. At least 8,890 FCEVs are on the road today, a far cry from the 53,000 the California Fuel Cell Partnership projected by the end of 2017.
“I don’t see a lot of automaker interest in hydrogen,” DeShazo argued. “Most automakers are betting on battery electric vehicles for the passenger market and delivery trucks.”
John Voelcker, the former editor of Green Car Reports who now covers electric cars and energy policy as a reporter and analyst, may be one of the industry’s most outspoken detractors. In a recent article for The Drive, he laid out the case for why FCEVs have not delivered on their many promises.
“Despite more than half a century of development, starting in 1966 with GM’s Electrovan, hydrogen fuel-cell cars remain low in volume, expensive to produce, and restricted to sales in the few countries or regions that have built hydrogen fueling stations,” he wrote.
When asked if hydrogen was the future of the automotive industry, Voelcker was unequivocal: “Absolutely not,” he told ABC News.
“If China suddenly decided its auto industry will adopt hydrogen vehicles, things might change,” he went on. “I am not a believer of FCEVs. It costs tens of billions of dollars to set up a hydrogen fueling network that has industrial strength compression equipment” to fuel these vehicles, he said.
Both Voelcker and DeShazo pointed out that the production of hydrogen — if not made from renewable energy such as natural gas or solar — causes greenhouse emissions.
“If the goal is reducing climate change gas per mile driven, electricity is simply better at doing that,” Voelcker said. “More CO2 is associated with hydrogen cars.”
Mixed outlook for automakers
Not all automakers are convinced that hydrogen can help them meet their emissions targets. Audi will stop development of its hydrogen-powered vehicles, including its flashy h-tron concept that was expected to hit the market in 2025, according to German newspaper Die Zeit.
“We will not be able to produce sufficient quantities of the hydrogen required for propulsion in the next few decades in a CO2-neutral manner. I therefore do not believe in hydrogen for use in cars,” Markus Duesmann, Audi’s CEO, said in an interview.
Volkswagen has also decided against the technology, with Herbert Dies, the company’s chief, telling industry insiders in July: “It doesn’t make a lot of sense at this point to think about bringing hydrogen into passenger cars.”
Unlike its German counterparts, BMW has not ruled out hydrogen. The Bavarian automaker said in a tweet that it would produce an X5 SUV with its second generation hydrogen fuel cell powertrain by 2022. General Motors, along with partner Honda, said it remains “committed to fuel cells as a complement to battery-electric propulsion” and the manufacture of fuel cells will take place at the company’s facility in Brownstown, Michigan.
GM will also supply its Hydrotech fuel cell systems to electric start-up Nikola’s heavy duty semi-trucks.
Honda Motor
Whether hydrogen can succeed depends on how willing the stakeholders — automakers, station developers and local governments — are willing to invest in the technology. Honda has only sold 1,617 Clarity Fuel Cell vehicles in nearly four years and the company is “pursuing multiple ZEV (Zero Emission Vehicle) pathways” in an effort to reduce CO2 emissions, a spokesperson said.
Toyota is actively working with elected officials, NGOs, utilities and energy companies to increase the access to hydrogen. A number of refueling stations have been built or are almost complete in the Northeast with Colorado, Oregon, Washington state and Texas eyed as the next growth areas.
Toyota engineer Birdsall said 2021 Mirai owners will receive $15,000 in free hydrogen, or enough money to cover the first 67,000 miles. It costs about $90 to fill up the car’s 5.6 kilogram tank. These giveaways could help change consumers’ minds — at least in California — to try an FCEV. Hydrogen’s limitations, however, may be too much for any automaker to overcome in the long term.
“We don’t want to put all our eggs in one basket,” Birdsall noted. “Both BEVs and hydrogen fuel cells are the future.”
Watch Our YouTube Video for the Next Phase of our Nano Enabled Battery and Super Capacitors – “The Magnum”
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A new carbon membrane could someday be used in commercial desalination plants
Leiden chemists have created a new ultrathin membrane only one molecule thick. The membrane can produce a hundred times more power from seawater than the best membranes used today. The researchers have published their findings in Nature Nanotechnology.
Thin and porous
When fresh and saltwater meet, an exchange of salt and other particles takes place. A membrane placed in water is able to harness energy from particles moving from one side to the other. A similar process can also be used to desalinate seawater. Leiden chemists have developed a new membrane that can produce a hundred times more energy than classic membranes and known prototype membranes in scientific literature.
How much power is generated depends on the thickness of the membrane and how porous it is. Researchers were able to create a carbon based membrane that is both porous and thin. That is why it can produce more energy than current membranes, which are either porous or thin, but not both.
Credit: Xue Liu
To create this new membrane, Xue Liu and Grégory Schneider spread a large number of oily molecules on a water surface. These molecular building blocks then form a thin film on their own. By heating the film, the molecules are locked in place, creating a stable and porous membrane. According to Xue Liu, the membrane can be adapted for specific requirements. Liu: “The membrane we’ve created is only two nanometers thick and permeable to potassium ions. We can change the properties of the membrane by using a different molecular building block. That way we can adapt it to suit any need.”
Graphene
The new carbon membrane is similar to graphene, a large flat membrane made up of only carbon atoms. But according to Grégory Schneider, this new membrane is in a whole different category. Schneider: “When making a membrane, a lot of researchers start out with graphene, which is very thin, but not porous. They then try to punch holes in it to make more permeable. We’ve done the reverse by assembling small molecules and building a larger porous membrane from those molecules. Compared to graphene, it contains imperfections, but that’s what gives it its special properties.”
This new membrane combines the best of both worlds. Schneider: “Much of the research in this field was focused on creating better catalysts, membranes were somewhat of a dead end. This new discovery opens up whole new possibilities for power generation, desalination and for building much more efficient fuel cells.”
Explore further
Let’s get the main question out of the way first. What is a hydrogen fuel cell vehicle? And how is it different to the host of battery-powered electric vehicles making their way onto the market by manufacturers from Jaguar and Audi to Nissan and Renault?
Hydrogen fuel cell cars have batteries onboard which store hydrogen and oxygen and power the vehicle with chemical reactions between the two elements to create water and energy.
Sometimes known as fuel cell electric vehicles (FCEVs), they have exhaust pipes but the only thing that escapes from them is water. The cars need refuelling, but with hydrogen rather than petrol or diesel fuel. For each fill of hydrogen, the car will gain 320-405km (200-250 miles) of range.
Meanwhile, conventional electric vehicles, often known as battery-operated electric vehicles (BEVs) are what we tend to think of as the most common fully electric cars. Like the Nissan Leaf, BMW i3, and Teslas.
These cars are powered by batteries which store charge in a similar way to phones, though many electric cars do manage to give themselves a slight recharge when braking, by converting the heat produced into electricity.
However, they’ll still need recharging at a mains electricity point after every 160-240km (100-150 miles). And that’s the main bugbear for many considering a BEV. With a standard EV and charging point, it could take up to 12 hours to fully charge a battery. Though rapid charge points exist, it will still take up to half an hour to add 160km of range.
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That compares with just a few seconds refuelling a petrol or diesel car on the forecourt. It’s here where fuel cell cars come into their own as a zero emissions alternative that’s also quick to refuel. Refuelling with hydrogen will take a couple of minutes, similar to the current practice.
With the basics out of the way, we asked two experts for their take on this new tech and when, if ever, we’ll see it taking the automotive industry by storm.
“Hydrogen car development has taken a back seat due to the fact that electric vehicles are more popular among the public,” Mark Barclay, e-commerce manager at GSF Car Parts, tells Euronews Living.
“But there are benefits to hydrogen that outweigh electric — sometimes literally, as hydrogen fuel cells are much lighter than powerful batteries. As you can top up a hydrogen car much quicker than charging your electric model, they’re perfect for public transport and businesses that can’t afford vehicle downtime.”
The decision to buy an electric or non-combustion engine car comes down to four key criteria:
That’s according to Jeremy Parkes, global business lead for electric vehicles at Norwegian renewable energy tech consultancy and classification society DNV GL, who researches buying habits and what the future will hold for the roads.
“In terms of range, current hydrogen fuel cell electric vehicle models are slightly better than battery electric vehicles,” he says. “However, when looking at performance, the price point and the availability of recharging/refuelling, EVs are winning.”
“Although refuelling a FCEV is very similar in time to an internal combustion engine vehicle, the refuelling options are very limited and an expansion of the refuelling infrastructure is very expensive compared to the expansion of the EV charging infrastructure, mainly because there is already an electrical grid in place in most areas where cars typically need to be charged,” says Parkes.
“BEVs can already be conveniently charged at the passenger’s home, something that is not be possible for FCEVs. It should also be noted that the CO2 emissions from a BEV over its lifetime are not only significantly lower than an ICE vehicle but are also lower than FCEV, where the majority of hydrogen is generated using fossil fuels, through methane steam reforming.”
Honda planned to add hydrogen fuelling when it opened ‘Europe’s most advanced public electric vehicle charging station’ in 2017 Honda
The experts agree that a major factor preventing uptake at the moment is the prohibitive cost. Barclay adds: “Hydrogen fuel cells are very expensive, and there are very few places to refill in the UK, so the infrastructure just isn’t there to support the technology at the moment.
There are also safety concerns among the public around the production of hydrogen and storage facilities, as hydrogen gas is extremely flammable.”
“BEVs are already much cheaper, both the upfront and running costs for FCEVs are higher than for BEVs,” Parkes tells Euronews Living.
“Many new technologies struggle getting to scale which is crucial for the reduction of costs, since every time the production levels of a new technology increase the costs will decrease. For battery technology, we see a cost reduction of 19% for every doubling of the production levels.
Already we see the total number of BEVs being manufactured and sold globally in the millions, compared to hydrogen, which amount to just a few tens of thousands being sold to date.”
“Toyota, Honda, and Hyundai already have hydrogen cars on the market and Europe is catching up,” says Barclay. But he still thinks hydrogen cars “clearly have some way to go before they take over the roads” to the extent electric and hybrid cars have.
“The industry still needs to adapt to these new technologies as investments continue to be made to improve the concept of hydrogen powered vehicles, mostly to reduce cost,” he says. “So, hydrogen cars should begin to threaten electric vehicles or even overtake them within the decade, and businesses should be prepared for that.”
A fleet of fuel cell Toyota Mirai cars have racked up more than a million miles on the streets of London.Toyota
Parkes disagrees. “Ultimately it comes down to two factors. The proven scalability, and hence the cost reductions of battery technology, and the poor charging infrastructure for fuel cell cars mean that BEVs are expected to dominate the passenger vehicle market in the coming decades.”
He adds: “There are still some expectations in the market that fuel cell technology might scale-up.
For instance, by the rise of producing hydrogen though electrolysis, driven by very low electricity prices due to excess renewable energy, which could form a business case for hydrogen production.
However, it should be highlighted that with current technology this is very inefficient, approximately three times as much energy needs to be put into the process compared to the energy available in the hydrogen produced.”
Critics have slammed reports of unsustainable sourcing for the lithium ion batteries that go into conventional electric vehicles. However, “they ignore the innovation push in the industry that will lead to major cost reductions, as well as alternative ecological battery solutions”, Parkes says.
“Not only are BEVs more ecological in the short term, but also more sustainable and responsible in the long term.
The industry is making rapid advances as we scale-up, developing new battery types for EVs such as the use of solid-state batteries, which can charge and discharge faster and have a higher energy density than li-ion batteries, as well as using less rare metals in its production process.”
So, that’s it. A beginners’ guide to the world of hydrogen fuel cell vehicles and how they compare to the mainstream electrical vehicle. If you’ve got any more questions you’d like answered, let us know in the comments section below.
Nikola Motors, better known for its electric fuel-cell semi-trucks, is today unveiling a concept for a new electric pickup with a battery/fuel-cell hybrid powertrain enabling 600 miles of range, 0-60 mph acceleration in 2.9 seconds, and more.
The Arizona-based company is planning to use battery packs in its larger hydrogen semi trucks and all-electric powertrains in its smaller and shorter-distance trucks.
After announcing their plans for trucks in 2015, the startup started expanding its portfolio with electric UTVs, watercraft, and more.
Now they are also expanding to electric pickup trucks and unveiled the Nikola Badger today.
Trevor Milton, CEO, Nikola Corporation, commented on the announcement:
Nikola has billions worth of technology in our semi-truck program, so why not build it into a pickup truck? I have been working on this pickup program for years and believe the market is now ready for something that can handle a full day’s worth of work without running out of energy. This electric truck can be used for work, weekend getaways, towing, off-roading or to hit the ski slopes without performance loss. No other electric pickup can operate in these temperatures and conditions.
They listed the following specs for the Nikola Badger
They claim a hybrid battery/fuel cell powertrain that can operate independently for 300 miles of battery-only range and 300 miles of fuel cell range.
While they are announcing specs, they are not unveiling a prototype just yet. They are only showing some concept images:
The company says that the vehicle will be fully unveiled at their Nikola World 2020 event in September. They will start to take reservations at that time.
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 journal Nature Communications, researchers from universities in the UK, Portugal, Germany and Hungary describe how pulsing electric currentthrough a layered catalyst has allowed them to almost double the amount of hydrogen produced per millivolt of electricity used during the process.
Electrolysis, a process which is likely familiar to anyone who studied chemistry at high 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 or solar 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 the energy for 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
More information: The rapid electrochemical activation of MoTe2 for the hydrogen evolution reaction, Nature Communicationsdoi.org/10.1038/s41467-019-12831-0 , www.nature.com/articles/s41467-019-12831-0
Journal information: Nature Communications
Provided by University of Glasgow
A hydrogen fuel tank. Photographer: Tomohiro Ohsumi/Bloomberg
THE CEO Who Wants Italy to Love Hydrogen Power
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.
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
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 catalytic activity.
“There’s always going to be an initial cost for producing a fuel cell with platinum 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 without platinum, 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 films 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.
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 covalent bonding 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 atoms. 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 graphene 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
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