A new system for producing green hydrogen cheaply and efficiently
A study developed jointly by IIT and the spin-off BeDimensional has identified a solution based on ruthenium particles and a solar-powered electrolytic system
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IIT AND BEDIMENSIONAL'S RESEARCHERS USED NANOPARTICLES OF RUTHENIUM, A NOBLE METAL THAT IS SIMILAR TO PLATINUM IN ITS CHEMICAL BEHAVIOUR BUT FAR CHEAPER, TO SERVE AS THE ACTIVE PHASE OF THE ELECTROLYSER’S CATHODE, LEADING TO AN INCREASED EFFICIENCY OF THE OVERALL ELECTROLYZER.
view moreCREDIT: IIT-ISTITUTO ITALIANO DI TECNOLOGIA
Genoa (Italy), 13 December 2023 - What does it take to produce green hydrogen more efficiently and cheaply? Apparently, small ruthenium particles and a solar-powered system for water electrolysis. This is the solution identified by a joint team involving the Istituto Italiano di Tecnologia (Italian Institute of Technology, IIT) of Genoa, and BeDimensional S.p.A. (an IIT spin-off). The technology, developed in the context of the Joint-lab’s activities and recently published in two high-impact factor journals (Nature Communications and the Journal of the American Chemical Society) is based on a new family of electrocatalysts that could reduce the costs of green hydrogen production on an industrial scale.
Hydrogen is considered as a sustainable energy vector, alternative to fossil fuels. But not all hydrogen is the same when it comes to environmental impact. Indeed, the main way hydrogen is produced nowadays is through the methane steam reforming, a fossil fuel-based process that releases carbon dioxide (CO2) as a by-product. The hydrogen produced by this process is classified as “grey” (when CO2 is release into the atmosphere) or “blue” (when CO2 undergoes capture and geological storage). To significantly reduce emissions to zero by 2050 these processes must be replaced with more environmentally sustainable ones that deliver “green” (i.e. net-zero emissions) hydrogen. The cost of “green” hydrogen critically depends on the energy efficiency of the setup (the electrolyzer) that splits water molecules into hydrogen and oxygen.
The researchers from the joint team of this discovery have developed a new method that guarantees greater efficiency than currently known methods in the conversion of electrical energy (the energy bias exploited to split water molecules) into the chemical energy stored in the hydrogen molecules that are produced. The team has developed a concept of catalyst and have used renewable energy sources, such as the electrical energy produced by a solar panel.
“In our study, we have shown how it is possible to maximise the efficiency of a robust, well-developed technology, despite an initial investment that is slightly greater than what would be needed for a standard electrolyzer. This is because we are using a precious metal such as ruthenium”, commented Yong Zuo and Michele Ferri from the Nanochemistry Group at IIT in Genoa.
The researchers used nanoparticles of ruthenium, a noble metal that is similar to platinum in its chemical behaviour but far cheaper. Ruthenium nanoparticles serve as the active phase of the electrolyser’s cathode, leading to an increased efficiency of the overall electrolyzer.
“We have run electro-chemical analyses and tests under industrially-significant conditions that have enabled us to assess the catalytic activity of our materials. Additionally, theoretical simulations allowed us to understand the catalytic behaviour of ruthenium nanoparticles at the molecular level; in other words, the mechanism of water splitting on their surfaces”, explained Sebastiano Bellani and Marilena Zappia from BeDimensional, who were involved in the discovery. “Combining the data from our experiments with additional process parameters, we have carried out a techno-economic analysis that demonstrated the competitiveness of this technology, when compared to state-of-the-art electrolysers”.
Ruthenium is a precious metal that is obtained in small quantities as a by-product of platinum extraction (30 tonnes per year, as compared to the annual production of 200 tonnes of platinum) but at a lower cost (18.5 dollars per gram as opposed to 30 dollars for platinum). The new technology involves the use of just 40 mg of ruthenium per kilowatt, in stark contrast with the extensive use of platinum (up to 1 gram per kilowatt) and iridium (between 1 and 2.5 grams per kilowatt, with iridium price being around 150 dollars per gram) that characterize proton-exchange membrane electrolysers.
By using ruthenium, the researchers at IIT and BeDimensional have improved the efficiency of alkaline electrolysers, a technology that has been used for decades due to its robustness and durability. For example, this technology was on board of the Apollo 11 capsule that brought humanity to the moon in 1969. The new family of ruthenium-based cathodes for alkaline electrolysers that has been developed is very efficient and has a long operating life, being therefore capable of reducing the production costs of green hydrogen.
“In the future, we plan to apply this and other technologies, such as nanostructured catalysts based on sustainable two-dimensional materials, in up-scaled electrolysers powered by electrical energy from renewable sources, including electricity produced by photovoltaic panels”, concluded the researchers.
JOURNAL
Journal of the American Chemical Society
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Ru–Cu Nanoheterostructures for Efficient Hydrogen Evolution Reaction in Alkaline Water Electrolyzers
Unlocking hydrogen’s potential for renewable energy storage, transport
A new NSF-supported collaboration, led by Lehigh University, aims to improve current liquid organic hydrogen carriers and use AI to identify novel approaches that could lay the groundwork for a global renewable energy supply chain
Hydrogen is the lightest, most abundant element on earth. It also serves as an energy carrier, and as such, holds great promise when it comes to decreasing the global reliance on fossil fuels. The problem, however, is that current methods of storing and transporting the molecule can be unsafe, inefficient, and expensive.
A multi-institution, multidisciplinary group of researchers led by Lehigh University recently received a $1.7 million grant from the National Science Foundation to fund the collaborative development of a new class of molecules, chemistries, and chemical processes to better store and transport green energy across the globe.
The team, which is led by Srinivas Rangarajan, an associate professor of chemical and biological engineering in Lehigh’s P.C. Rossin College of Engineering and Applied Science, includes investigators Dharik Mallapragada, New York University; Elizabeth Biddinger, City College of New York (CCNY); and Daniel Resasco and Steven Crossley, University of Oklahoma.
“This is a convergent effort where we’re looking at this problem in a multiscale manner,” says Rangarajan, “from the atomic scale all the way up to global supply chains.”
Variable energy sources, such as wind and solar farms, can generate more electricity than is needed at any given time. If a system were to pass that energy through water, the water would split into oxygen and hydrogen, with the resulting hydrogen molecules containing the renewably generated energy. Those molecules could then be stored and transported to where power is needed—like a manufacturing or chemical plant, a university or school, or a community of houses or apartments—and later burned to harness the reserved energy.
“Hydrogen is one of the lightest energy carriers, which is good because the amount of energy per gram of hydrogen is very high,” says Rangarajan. “But a gram of hydrogen also requires a lot of storage volume, unless you go to really low temperatures and really high pressure. So if you want to transport it over long distances, liquified hydrogen has to be stored at cryogenic temperatures at hundreds of pounds of atmospheric pressure.”
One technique currently in use to overcome this two-fold problem of transport and storage utilizes liquid organic hydrogen carriers, or LOHCs. Essentially, hydrogen is added to an organic molecule—called an hydrogen-lean molecule—that is liquid under ambient conditions to form another molecule which is also liquid, the hydrogen-rich carrier.
“At the point where hydrogen is being produced, you hydrogenate that hydrogen-lean molecule to store the hydrogen and form the hydrogen-rich molecule, which you ship to wherever it’s needed,” he says. “At the point of demand, you do what’s called dehydrogenation chemistry, which releases the hydrogen. The spent hydrogen-lean molecule is then shipped back to the point of supply of hydrogen where it can be reused.”
The LOHCs are very stable molecules, he says, and can be stored and transported using the same infrastructure used for hydrocarbons, including ships and trucks.
“There are demonstration projects going on around the world using this technology, and it could change the energy supply chain on a global level,” he says. “You can’t transport electricity from one continent to another, but you can transport energy through hydrogen.”
Rangarajan and his colleagues are devising a method that could improve how LOHCs are used in several ways.
They’re investigating a new class of alcohol-based molecules, a new class of chemistries, and associated chemical processes that could potentially increase the hydrogen storage capacity of the LOHC technology, and make the molecules safer to transport and handle. Their approach could also make the process more efficient by decreasing the energy penalty associated with the hydrogenation and dehydrogenation processes, steps in which some energy is normally lost.
Those steps also require catalysts—such as platinum or palladium—that can be expensive, he says.
“That’s where the novelty comes in,” he says. “We feel there are some intrinsic chemistries that can be driven by electricity instead of by heat, which could be helpful and much easier from a thermodynamic and kinetic perspective.”
To that end, the University of Oklahoma collaborators will study heterogeneous catalytic approaches to hydrogenate/dehydrogenate molecules. CCNY researchers will study analogous electrochemical approaches. NYU researchers will study the overall process economics, sustainability, and global impact of the choice of LOHCs and chemistries. Rangarajan will build models that connect molecular and chemistry information to process-level metrics.
The group will initially focus on a molecule they’ve already identified as promising. During the second half of the four-year project, they’ll employ artificial intelligence tools to screen for alternative hydrogen carriers with significant potential.
“There are 10 to the power of 60 small organic molecules that could potentially be synthesized,” says Rangarajan. “If you’re looking at large molecules, there are even more combinations. It’s actually a very difficult problem to solve, but there are some novel AI-based algorithms that can get you the right molecule and the right chemistries that you can then test with experiments.”
Identifying the correct combinations and chemistries at the atomic level could ultimately have significant repercussions on the global scale.
“We’re at a tipping point now with hydrogen,” says Rangarajan. “The U.S. is planning to spend $8 billion to incentivize building a dozen or so hydrogen hubs to produce hydrogen and use it to power transportation and industry. A breakthrough could open up new economies around the world and create a global supply of renewable energy.”
About Srinivas Rangarajan
Srinivas Rangarajan is an associate professor in the Department of Chemical and Biomolecular Engineering at Lehigh University.
Research in his group is at the intersection of heterogeneous catalysis, reaction engineering, and process systems engineering. The group develops and applies a variety of computational tools to model and design catalytic systems and materials that are governed by complex chemistries.
Rangarajan is the principal developer of the open source computational package, RING—Rule Input Network Generator—which, for any chemical feedstock and a corresponding set of basic chemistry rules, generates all possible reaction pathways. RING allows for modeling of massive and complex reaction networks.
Rangarajan joined the faculty of the P.C. Rossin College of Engineering and Applied Science in 2017, after serving as a postdoctoral scholar at the University of Wisconsin, Madison. He received his B.Tech. (2007) from the Indian Institute of Technology, Madras, and PhD (2013) from the University of Minnesota, both in chemical engineering. His industrial experience includes previous employment at Shell Global Solutions in the Netherlands and India as a senior associate technologist in hydroprocessing.
About Elizabeth J. Biddinger
Elizabeth J. Biddinger is an Associate Professor in Chemical Engineering at The City College of New York, CUNY, where she has been on the faculty since 2012. Her research encompasses the broad areas of green chemistry and energy, specifically using electrochemical reaction engineering, electrocatalysis and novel electrolytes such as ionic liquids. Prof. Biddinger is the recipient of the 2018 US Department of Energy Early Career Award to study electroreduction of biomass-derived chemicals and fuels, the 2016 ECS-Toyota Young Investigator Award for work in reversible ionic liquids as battery safety switches, and the 2014 CUNY Junior Faculty in Research Award in Science and Engineering sponsored by the Sloan Foundation for work in CO2 electroreduction. Prior to joining CCNY, Prof. Biddinger was a post-doctoral fellow at Georgia Institute of Technology. She obtained her PhD in 2010 from The Ohio State University and her BS in 2005 from Ohio University, both in chemical engineering.
About Steven Crossley
Steven Crossley is Sam A. Wilson Professor in the School of Sustainable Chemical, Biological and Materials Engineering at the University of Oklahoma. He serves as Associate Director of the Institute for Resilient Environmental and Energy Systems (IREES), faculty advisor for the OU chapter of the American Indian Science and Engineering Society (AISES), and co-founding member of https://gradschoolthriving.com. He received his PhD from the University of Oklahoma (2009). His group’s research focuses on understanding fundamental reaction mechanisms in complex reaction environments for the conversion of renewable biomass-derived feedstocks, CO2 free hydrogen, and the selective conversion of waste polymers.
About Dharik S. Mallapragada
Dharik S. Mallapragada is a Principal Research Scientist at the MIT Energy Initiative (MITEI), where he leads the Sustainable Energy Transitions (SET) Group. Dr. Mallapragada’s research focuses on planning and operating resilient, low-carbon energy systems as well as conceptualization, design and integration of emerging energy technologies. Mallapragada is the co-developer of DOLPHYN, an open-source energy system model to support multi-vector infrastructure planning for the energy transition and accelerating technology development. Prior to MIT, Mallapragada spent nearly five years in the energy industry working on a range of sustainability-focused research topics. Mallapragada holds a MS and PhD in Chemical Engineering from Purdue University and a B.Tech. in Chemical Engineering from the Indian Institute of Technology, Madras, India. He will be joining the Chemical and Biomolecular Engineering department at New York University as an assistant professor in January 2024.
About Daniel Resasco
Daniel Resasco obtained his PhD (1984) from Yale University. He specializes in heterogeneous catalysis and nanostructured materials. Author of 330+ publications and 40+ industrial patents. He is a member of the National Academy of Inventors and the National Academy of Sciences of Argentina. He has been editor of Catalysis Reviews and the Journal of Catalysis, as well as member of the editorial boards of Journal of Catalysis, Applied Catalysis A, Applied Catalysis B, Chinese J. Catalysis, and Catalysis Reviews. He has been Chair of the Catalysis Division of the American Chemical Society and President and co-founder of the Great Plains Catalysis Society.
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