North Carolina State University researchers have developed a new technique for extracting hydrogen gas from liquid carriers. The new technique is faster, less expensive and more energy efficient than previous concepts.

Milad Abolhasani, corresponding author of a paper on the new technique and an associate professor of chemical and biomolecular engineering at NC State offered background, “Hydrogen is widely viewed as a sustainable energy source for transportation, but there are some technical obstacles that need to be overcome before it can be viewed as a practical alternative to existing technologies. One of the big obstacles to the adoption of a hydrogen economy is the cost of storage and transportation.”

Hydrogen fuel does not result in CO2 emissions. And hydrogen refueling stations could be located at existing gas stations, taking advantage of existing infrastructure. But transporting hydrogen gas is dangerous, so hydrogen needs to be transported via a liquid carrier. A key obstacle for this strategy is that extracting hydrogen from the liquid carrier at destination sites, such as fueling stations, is energy intensive and expensive.

Sunlight powers the hydrogen free from a liquid carrier for a consumer & the liquid carrier is sent back for a recycling. Image Credit: North Carolina State University. Click the NCSU link above for a larger view and the ChemSusChem link below for the full paper details.

“Previous research has shown that it is possible to use photocatalysts to release hydrogen gas from a liquid carrier using only sunlight,” Abolhasani said. “However, existing techniques for doing this were laborious, time consuming and required a significant amount of rhodium – a metal that is very expensive.”

Malek Ibrahim, first author of the paper, “Continuous Room‐Temperature Hydrogen Release from Liquid Organic Carriers in a Photocatalytic Packed‐Bed Flow Reactor”, published in ChemSusChem and, a former postdoctoral researcher at NC State explained difference about the new technique, “We’ve developed a technique that applies a reusable photocatalyst and sunlight to extract hydrogen gas from its liquid carrier more quickly and using less rhodium – making the entire process significantly less expensive. What’s more, the only byproducts are hydrogen gas and the liquid carrier itself, which can be reused repeatedly. It’s very sustainable.”

One key to the success of the new technique is that it is a continuous-flow reactor. The reactor resembles a thin, clear tube packed with sand. The “sand” consists of micron-scale grains of titanium oxide, many of which are coated with rhodium. The hydrogen-carrying liquid (1,2,3,4-tetrahydroquinoline) is pumped into one end of the tube. The rhodium-coated particles line the outer part of the tube, where sunlight can reach them. These particles are photoreactive catalysts that, in the presence of sunlight, react with the liquid carrier to release hydrogen molecules as a gas.

The researchers precisely engineered the system so that only the outer grains of titanium oxide are coated with rhodium, ensuring the system uses no more rhodium than is necessary.

Abolhasani pointed out the difference, “In a conventional batch reactor, 99% of the photocatalyst is titanium oxide and 1% is rhodium. In our continuous flow reactor, we only need to use 0.025% rhodium, which makes a big difference in the final cost. A single gram of rhodium costs more than $500.”

In their prototype reactor, the researchers were able to achieve a 99% yield – meaning that 99% of the hydrogen molecules were released from the liquid carrier – in three hours.

Ibrahim said, “That’s eight times faster than conventional batch reactors, which take 24 hours to reach 99% yield. And the system should be easy to scale up or scale out to allow for catalyst reuse on commercial scale – you can simply make the tube longer or merge multiple tubes running in parallel.”

The flow system can run continuously for up to 72 hours before its efficiency decreases. At this point, the catalyst can be “regenerated” without removing it from the reactor – it’s a simple cleaning process that takes about six hours. The system can then be restarted and run at full efficiency for another 72 hours.

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This is good news especially for hydrogen enthusiasts. It takes one segment of a hydrogen economy and offers a much safer storage and transport solution. Pipelined this could very well be a good path. Trucked and spilled on a sunny day might lead to a major catastrophe. And it doesn’t solve the risks at the production end, although there is considerable industrial experience on hand now. At the consumption end the H2 looks to be freed up to its fully ignitable state. The mere idea of average consumers driving about with compressed H2 gas aboard is a frightening idea.

Japan Advanced Institute of Science and Technology scientists added a specific polymer composite to the silicon anode of lithium-ion batteries, which significantly increased their lifetime.

Lithium-ion batteries (LIBs) power electric vehicles and electronics. With the prevalence of these set to increase, efforts have been directed towards improving the performance and longevity of LIBs. Now researchers have shown that adding a specific polymer composite binder to the silicon anode of LIBs can improve its structural stability significantly, making it viable for much more powerful, long-lasting LIBs, and changing the future of the technologies it drives.

The structure of the composite binder consisting of P-BIAN and PAA linked by hydrogen bonds. Image Credit: Japan Advanced Institute of Science and Technology. For more and larger images click the above link to Japan Advanced Institute of Science and Technology.

Think of a battery, and the term lithium-ion most likely comes to mind. Because of its light weight, high-energy density, and ability to deliver three times as much current as other types of rechargeable batteries, lithium-ion batteries (LIBs) have become the dominant type of battery in both low-power consumer electronic devices, such as mobile phones, and high-power applications, such as electric vehicles and energy storage.

Any typical lithium-ion battery today consists of a positive electrode (cathode) made up of a lithium-containing compound, a negative electrode (anode) made up of graphite, and electrolyte – the layer in between the electrodes through which ions flow. When a battery is charged, lithium ions flow from the cathode to the anode, where they are stored. During the discharge process, the lithium is ionized and moves back to the cathode.

Recently, there has been a growing interest in using silicon as the anode material because it is more abundant, and therefore cheap, and has a higher theoretical discharge capacity than graphite. However, it has a key disadvantage: repeated charging and discharging causes the silicon particles to expand and rupture. This results in the formation of a thick solid-electrolyte interface (SEI) between the electrolyte and the anode, which hinders the movement of lithium ions between the electrodes.

To improve the performance of silicon anodes in LIBs, a team led by Professor Noriyoshi Matsumi, and also including Dr. Agman Gupta and Senior Lecturer Rajashekar Badam, from Japan Advanced Institute of Science and Technology (JAIST), has developed a binder for the silicon particles, which can improve their stability and maintain a thin SEI layer. Now, in contrast to a thick SEI layer, a thin one is beneficial because it prevents the anode and electrolyte from spontaneously reacting with each other.

The results of the study have been published in ACS Applied Energy Materials.

The binder is a polymer composite consisting of an n-type conducting polymer poly(bisiminoacenaphthenequinone) (P-BIAN) and a carboxylate-containing polymer poly(acrylic acid) (PAA), each linked to the other via hydrogen bonds. The composite polymer structure holds the silicon particles together like a net and prevents them from rupturing. The hydrogen bonds between the two polymers permit the structure to self-repair, as the polymers can reattach themselves if they break away at any point. Moreover, the n-doping ability of P-BIAN improves the conductivity of the anode and maintains a thin SEI by limiting the electrolytic decomposition of the electrolyte on the anode.

To test the binder, the researchers constructed an anodic half-cell consisting of silicon nanoparticles with graphite (Si/C), the binder (P-BIAN/PAA) and an acetylene black (AB) conductive additive. The Si/C/(P-BIAN/PAA)/AB anode was put through a repeated charge-discharge cycle. The P-BIAN/PAA binder was observed to stabilize the silicon anode and maintain a specific discharge capacity of 2100 mAh g-1 for over 600 cycles. In contrast, the capacity of the bare silicon-carbon anode dropped to 600 mAh g-1 within 90 cycles.

After the test, the researchers disassembled the anode and examined the material for any cracks that might have resulted from silicon rupture. A spectroscopic and microscopic examination after 400 cycles revealed a smooth structure with only a few microcracks indicating that the addition of the binder was able to improve the structural integrity of the electrode and maintain a uniform SEI.

The results demonstrate that the addition of the binder can improve the characteristics of the silicon anode and make it practically feasible. “The design and application of novel polymer composites comprising n-type conducting polymers (CPs) and proton donating polymers with hydrogen bonded networks, like P-BIAN/PAA, hold a promising future in high-capacity electrode materials,” said Prof. Matsumi.

As the demand for lithium-ion batteries increases, silicon, which is the eighth-most abundant material on earth, will be a promising environment-friendly alternative to graphite. The improvements to its structural stability and its conductivity with the use of binders will make it more suitable for use in future lithium-ion batteries. “This composite binder design principle will enable wider diffusion of EVs, creation of other battery driven vehicles, and drones, which requires a higher energy density for advanced performance,” commented Prof. Matsumi.

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This news might be a mile marker for lithium ion battery chemistry. The comment “maintain a specific discharge capacity of 2100 mAh g-1 for over 600 cycles” is a major improvement that just begs a repetition confirmation. No noticeable capacity drop over 600 cycles seems like a performance revolution considering the number of battery replacements your humble writer’s cell phone has been through.

There remains the cost of production and scalability. One does hope this research gets the attention it deserves as for now the EV is simply out of economic reach for all but the quite well to do.

Rice University chemists have processed waste plastic from end-of-life F-150 trucks into graphene for composite materials in new vehicles. The suggestion is that parts of an old car gets turned into graphene that could come back as a better part for new cars.

Rice University chemists working with researchers at the Ford Motor Company are turning plastic parts from “end-of-life” vehicles into graphene via the university’s flash Joule heating process.

Block diagram of the custom designed dual capability FJH station for low current (LC) and high current (HC) discharge, with a working procedure displayed below. Image Credit: Rice University. Click the Rice link and the Communications Engineering link for more images and information.

Today the average SUV contains up to 350 kilograms (771 pounds) of plastic that could sit in a landfill for centuries. But now there is a recycling process reported in the debut issue of a new Nature journal, Communications Engineering.

The goal of the project led by Rice chemist James Tour and graduate student and lead author Kevin Wyss was to reuse that graphene to make enhanced polyurethane foam for new vehicles. Tests showed the graphene-infused foam had a 34% increase in tensile strength and a 25% increase in low-frequency noise absorption. That’s with only 0.1% by weight or less of graphene.

And when that new car is old, the foam can be flashed into graphene again.

Tour explained, “Ford sent us 10 pounds of mixed plastic waste from a vehicle shredding facility. It was muddy and wet. We flashed it, we sent the graphene back to Ford, they put it into new foam composites and it did everything it was supposed to do. Then they sent us the new composites and we flashed those and turned them back into graphene. It’s a great example of circular recycling.”

The researchers cited a study that estimates the amount of plastic used in vehicles has increased by 75% in just the past six years as a means to reduce weight and increase fuel economy.

Segregating mixed end-of-life plastic by type for recycling has been a long-term problem for the auto industry, Tour said, and it’s becoming more critical because of potential environmental regulations around end-of-life vehicles. “In Europe, cars come back to the manufacturer, which is allowed to landfill only 5% of a vehicle,” he said. “That means they must recycle 95%, and it’s just overwhelming to them.”

Much of the mixed plastic ends up being incinerated, according to co-author Deborah Mielewski, technical fellow for sustainability at Ford, who noted the U.S. shreds 10 to 15 million vehicles each year, with more than 27 million shredded globally.

“We have hundreds of different combinations of plastic resin, filler and reinforcements on vehicles that make the materials impossible to separate,” she said. “Every application has a specific loading/mixture that most economically meets the requirements.”

“These aren’t recyclables like plastic bottles, so they can’t melt and reshape them,” Tour noted. “So, when Ford researchers spotted our paper on flash Joule heating plastic into graphene, they reached out.”

Flash Joule heating to make graphene, introduced by the Tour lab in 2020, packs mixed ground plastic and a cokeadditive (for conductivity) between electrodes in a tube and blasts it with high voltage. The sudden, intense heat – up to nearly 5,000° Fahrenheit – vaporizes other elements and leaves behind easy-to-solubilize, turbostratic graphene.

Flash heating offers significant environmental benefits, as the process does not require solvents and uses a minimum of energy to produce graphene.

To test whether end-of-life, mixed plastic could be transformed, the Rice lab ground the shredder “fluff” made of plastic bumpers, gaskets, carpets, mats, seating and door casings from end-of-life F-150 pickup trucks to a fine powder without washing or pre-sorting the components.

The lab flashed the powder in two steps, first under low current and then high current in a heater Wyss custom designed for the experiment.

Powder heated between 10 to 16 seconds in low current produced a highly carbonized plastic accounting for about 30 percent of the initial bulk. The other 70% was outgassed or recovered as hydrocarbon-rich waxes and oils that Wyss suggested could also be recycled.

The carbonized plastic was then subjected to high-current flashing, converting 85% of it into graphene while outgassing hydrogen, oxygen, chlorine, silicon and trace metal impurities.

The chance to incorporate life-cycle analysis (LCA) into a Rice research project was also a draw for Wyss. “I’m driven by sustainability, and it’s where I want to focus in my career,” he said.

The LCA involved comparing graphene from flashed car parts to that produced by other methods, and evaluating recycling efficiency. Their results showed flash Joule heating produced graphene with a substantial reduction in energy, greenhouse gas emissions, and water use when compared to other methods, even including the energy required to reduce the plastic shredder fluff to powder.

Ford has been using up to 60 pounds of polyurethane foam in its vehicles, with about 2 pounds of that being graphene-reinforced since 2018, according to co-author Alper Kiziltas, a technical expert at Ford research who focuses on sustainability and emerging materials. “When we got the graphene back from Rice, we incorporated it into our foam in very small quantities and saw significant improvement,” he said. “It exceeded our expectations in providing both excellent mechanical and physical properties for our applications.”

Graphene clearly has a future at Ford. The company first introduced it into a variety of other under-the-hood components and in 2020 added a graphene-reinforced engine cover. Kiziltas said the company expects to use it to reinforce hard plastics as well.

“Our collaborative discovery with Rice will become even more relevant as Ford transitions to electric vehicles,” Mielewski said. “When you take away the noise generated by the internal combustion engine, you can hear everything else in and outside the vehicle that much more clearly.”

“It’s much more critical to be able to mitigate noise,” she said. “So we desperately need foam materials that are better noise and vibration absorbers. This is exactly where graphene can provide amazing noise mitigation using extremely low levels.”

Other co-authors of the paper are Robert DeKleine and Rachel Couvreur of Ford. Tour is the T.T. and W.F. Chao Chair in Chemistry and a professor of materials science and nanoengineering.

The Air Force Office of Scientific Research (FA9550-19-1-0296), the Department of Energy National Energy Technology Laboratory (DE-FE0031794) and a National Science Foundation Graduate Research Fellowship supported the research.

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This is spectacular news! The plastic recycling matter has been almost a bewildering issue that is gaining more common notice all the time. Tiny bits of plastics are showing up inside of people and animals. It definitely time to get to solution(s) on this.

There aren’t many items built that don’t have plastics involved. We’ve some a long way on metals, and this news should help simplify the matter for the next huge material inventory – plastics.

As for the 70% outgassed oils and waxes. These are very likely quite valuable products. They won’t be heavy crude oils needing giant refineries and catalytic crackers. One hopes there are folks asking for samples from the Rice team so that opportunity can be researched and exploited in a recycling way.

Many thanks to the Rice team, the Ford collaborators and funding sources!

Shibaura Institute of Technology researchers recently investigated the possibility of storing liquid fuel within polymeric gel networks, preventing their fast evaporation, and demonstrating good combustion performance. Liquid fuels with high energy density, though used worldwide, are dangerous to transport and store owing to their volatility, which produces explosive gas mixtures. The Institute’s researchers’ work suggests a way for safer transport and storage of liquid fuels.

Researchers from SIT Japan show in a new study that chemically cross-linked polymeric gel networks can trap highly volatile liquid fuel molecules, such as ethanol, through physical interactions, thereby greatly reducing their evaporation rate and risks of fire accidents. Image Credit: Naoki Hosoya from SIT, Japan. Click the press release link above or the research paper link below for more images.

The team’s paper was published in Volume 444 of the Chemical Engineering Journal.

Liquid fuels with high energy density are essential in many applications where chemical energy is converted into controlled motion, such as in rockets, gas turbines, boilers, and certain vehicle engines. Besides their combustion characteristics and performance, it is also important to guarantee the safety and stability of these fuels when in use as well as during transport and storage.

One common hazard when dealing with liquid fuels is that they can evaporate quickly if given space, producing clouds of highly flammable gases. As one might expect, this can lead to catastrophic explosions or fire accidents. To tackle this problem, researchers have considered the use of gelled fuels, or fuels turned into thick gel-like substances from cold temperatures. Unfortunately, there are many aspects to optimize and hurdles to overcome before gelled fuels can go beyond the research phase.

Luckily, a team of researchers led by Prof. Naoki Hosoya from Shibaura Institute of Technology (SIT) and Prof. Shingo Maeda from Tokyo Institute of Technology (Tokyo Tech), Japan, recently investigated a more compelling solution to the safety problem of liquid fuels, namely storing them inside polymeric gel networks. In their study, the team analyzed the performance, advantages, and limitations of storing ethanol, a common liquid fuel, within a chemically cross-linked poly(N-isopropylacrylamide) (PNIPPAm) gel.

First, they checked whether trapping ethanol molecules within the long and chemically intertwined PNIPAAm polymer chains helped reduce its evaporation rate. To test this, the researchers created small spheres of PNIPAAm gel loaded with ethanol and placed them on an electronic scale to record how mass changed as ethanol vaporized. They also performed this experiment with an equivalent puddle of ethanol, with roughly the same surface area and mass as the gel sphere.

They found that storing ethanol within the polymer gel completely suppressed the fuel’s tendency to rapidly vaporize. This is likely due to how ethanol molecules are “trapped” in the gel.

Prof. Hosoya explained, “The polymeric gel contains innumerable three-dimensional polymer chains that are chemically cross-linked in a strong way. These chains bind the ethanol molecules through various physical interactions, limiting its evaporation in the process.”

Interestingly, the loaded gel does not behave like a wet towel. Whereas a wet towel would release its liquid if wrung, the polymeric gel did not let out ethanol easily under external forces.

With the problem of evaporation solved, the team moved on to examine the actual combustion characteristics of the ethanol in the polymeric gel network to see if they burnt efficiently. They ignited ethanol-loaded gel spheres of various sizes and observed the changes in their mass and shape profiles in real time. Based on this, they determined that the burning of the loaded PNIPAAm gel spheres consisted of two phases: a phase dominated by pure ethanol burning, followed by a second phase dominated by the burning of the PNIPAAm polymer itself.

Through a subsequent theoretical analysis of these results, the team came to an important conclusion: the first and main combustion phase of the loaded PNIPAAm gel spheres follows a constant droplet temperature model, also known as the “d2 law.” What this means is that the burning of the ethanol-loaded gel can be described by the same model used for liquid fuel droplets, hinting that their combustion performances should be similar.

From a long term perspective, this study is a stepping stone towards new ways to safely transport and store liquid fuels inside polymer gels, which could save many lives.

Prof. Hosoya explained, “Polymeric gel storage could prevent explosions and fire accidents by drastically reducing the evaporation of fuels and, in turn, the formation of flammable gaseous mixtures, which can readily happen following a leak in a storage facility. Much work still remains to be done on this front, such as checking the stability and performance of polymeric gels at different temperature, pressure, and humidity conditions, as well as developing simpler fabrication procedures and better ways to use these fuel-loaded gels in real engines.

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This is pretty encouraging news. The fuel industry has 150 plus years of experience in transporting fuels and for the bulk transport side its pretty safe. Its in the hands of end users where things get more dangerous. Often its simply being in the wrong place when the ignoramus lights up at a fueling station or other dumb action. And accidents do happen.

If you smell any fuel, get away and quickly call an expert in. Getting burned is a terrible thing to have happen – that likely might have been avoided.

Clemson University researchers have discovered a novel way to combine curcumin, the substance of interest in turmeric, and gold nanoparticles to create an electrode that requires 100 times less energy to efficiently convert ethanol into electricity.

In a surprise innovation, turmeric, a spice found in most kitchens, has an extract that could lead to safer, more efficient fuel cells.

In a collaboration the researchers at the Clemson Nanomaterials Institute (CNI) and their collaborators from the Sri Sathya Sai Institute of Higher Learning (SSSIHL) in India discovered the novel way to combine curcumin with gold nanoparticles.

The journal Nano Energy published the findings in a paper titled, “Green synthesis of a novel porous gold-curcumin nanocomposite for super-efficient alcohol oxidation.”

Gold curcumin nanocomposite activity, an image and a performance comparison. Image Credit: Clemson University. Click the links to the press release and the research paper for more information.

While the research team must do more testing, the discovery brings replacing hydrogen as a fuel cell feedstock one step closer.

Apparao Rao, CNI’s founding director and the R. A. Bowen Professor of Physics in the College of Science’s said, “Of all the catalysts for alcohol oxidation in alkaline medium, the one we prepared is the best so far.”

Fuel cells generate electricity through a chemical reaction instead of combustion. They are used to power vehicles, buildings, portable electronic devices and backup power systems.

Hydrogen fuel cells are highly efficient and do not produce greenhouse gases. While hydrogen is the most common chemical element in the universe, it must be derived from substances such as natural gas and fossil fuels because it occurs naturally on Earth only in compound form with other elements in liquids, gases or solids. The necessary extraction adds to hydrogen fuel cells’ cost and environmental impact.

In addition, hydrogen used in fuel cells is a compressed gas, creating difficult challenges for storage and transportation. Ethanol, an alcohol made from corn or other agricultural-based feedstocks, is safer and easier to transport than hydrogen because it is a liquid.

Lakshman Ventrapragada, a former student of Rao’s who worked as a research assistant at the CNI and is an alumnus of SSSIHL said, “To make it a commercial product where we can fill our tanks with ethanol, the electrodes have to be highly efficient. At the same time, we don’t want very expensive electrodes or synthetic polymeric substrates that are not eco-friendly because that defeats the whole purpose. We wanted to look at something green for the fuel cell generation process and making the fuel cell itself.”

The researchers focused on the fuel cell’s anode, where the ethanol or another feed source is oxidized.

Fuel cells widely use platinum as a catalyst. But platinum suffers from poisoning because of reaction intermediates such as carbon monoxide, Ventrapragada said. It is also very costly.

Ventrapragada designed the experiment during his thesis work in Rao’s CNI lab. The researchers used gold as a catalyst. Instead of using conducting polymers, metal-organic frameworks, or other complex materials to deposit the gold on the surface of the electrode, the researchers used curcumin because of its structural uniqueness. Curcumin is used to decorate the gold nanoparticles to stabilize them, forming a porous network around the nanoparticles. Researchers deposited the curcumin gold nanoparticle on the surface of the electrode at a 100 times lower electric current than in previous studies.

Ventrapragada noted that without the curcumin coating, the gold nanoparticles agglomerate, cutting down on the surface area exposed to the chemical reaction.

Rao explained, “Without this curcumin coating, the performance is poor. We need this coating to stabilize and create a porous environment around the nanoparticles, and then they do a super job with alcohol oxidation.

“There’s a big push in the industry for alcohol oxidation. This discovery is an excellent enabler for that. The next step is to scale the process up and work with an industrial collaborator who can actually make the fuel cells and build stacks of fuel cells for the real application,” he continued.

In addition the research could have broader implications than improved fuel cells. The electrode’s unique properties could lend itself to future applications in sensors, supercapacitors and more, Ventrapragada said.

In collaboration with the SSSIHL research team, Rao’s team is testing the electrode as a sensor that could help identify changes in the level of dopamine. Dopamine has been implicated in disorders such as Parkinson’s disease and attention deficit hyperactivity disorder. When members of the research team tested urine samples obtained from healthy volunteers, they could measure dopamine to the approved clinical range with this electrode using a cost-effective method compared to standard ones used today, Rao said.

“In the beginning stages of the project, we did not imagine other applications that gold-coated curcumin could support. However, before the end of the alcohol oxidation experiments, we were fairly confident that other applications are possible,” Ventrapragada said. “Although we don’t have a complete understanding of what’s happening at the atomic level, we know for sure that curcumin is stabilizing the gold nanoparticles in a way that it can lend itself to other applications.”

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On the face of the press release this all sounds just great. Your humble writer has a strong preference for fuel cells over batteries and light alcohols for hydrogen stabilization and storage. One hopes the press release means in stating “an electrode that requires 100 times less energy to efficiently convert ethanol into electricity” something well, understandable. One gets just a little lost with “100 times less”. Does that mean multiply by 0.01 for an answer? No one seems to know just what exactly is meant when using the phrase.

Meanwhile the abstract to the paper strongly suggests the “100 times less” energy thing might be in the creation of the catalyst.

While the press release is faithfully followed here and we’re near 60 days since asking the contact researcher about using the phrase, your humble writer is going ahead now with a lot less energy in the build of the catalyst and hopefully perhaps, a lot less activation energy to get a fuel cell up and running.

For now gold is less expensive than platinum and far more plentiful. More of it is in known deposits as well and its highly recyclable. A 20 gallon tank of ethanol fueling a highly efficient fuel cell could get an automobile a very long, safe and eco friendly way, indeed.


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