GT/ Record 19.31% efficiency with organic solar cells
Energy & green technology biweekly vol.51, 8th June — 22nd June
TL;DR
- Researchers have achieved a breakthrough power-conversion efficiency (PCE) of 19.31% with organic solar cells (OSCs), also known as polymer solar cells. This remarkable binary OSC efficiency will help enhance applications of these advanced solar energy devices.
- A new class of materials that can absorb low energy light and transform it into higher energy light might lead to more efficient solar panels, more accurate medical imaging and better night vision goggles.
- The next generation of sustainable energy technology might be built from some low-tech materials: rocks and the sun. Using a new approach known as concentrated solar power, heat from the sun is stored then used to dry foods or create electricity. A team has found that certain soapstone and granite samples from Tanzania are well suited for storing this solar heat, featuring high energy densities and stability even at high temperatures.
- For many technology enthusiasts, the metaverse has the potential to transform almost every facet of human life, from work to education to entertainment. Now, new research shows it could have environmental benefits, too.
- Scientists investigate the promising properties of a common, Earth-abundant salt.
- A new analysis led by a University of Wyoming researcher shows that brackish or salty groundwater has the potential to replace fresh water to cool coal- and natural gas-fired power plants and strengthen resilience in the energy infrastructure, although there’s a cost associated with doing so.
- A team of researchers has created a new supply chain model which could empower the international hydrogen renewable energy industry.
- A team has developed a new catalyst composed of elements abundant in the Earth. It could make possible the low-cost and energy-efficient production of hydrogen for use in transportation and industrial applications.
- Researchers have developed a chemical process that can disassemble the epoxy composite of wind turbine blades and simultaneously extract intact glass fibers as well as one of the epoxy resin’s original building blocks in a high quality. The recovered materials could potentially be used in the production of new blades.
- Researchers develop a fabrication method to increase the efficacy and longevity of membrane separation technology. The team created a nanofibrous membrane with electrospinning, in which a liquid polymer droplet is electrified and stretched to make fibers, and increased the roughness of the membrane surface by loading it with silver nanoparticles. In water, this rough surface promotes a stable layer of water, which acts as a barrier to prevent oil droplets from entering the membrane.
- And more!
Green Technology Market
Green technology is an applicable combination of advanced tools and solutions to conserve natural resources and environment, minimize or mitigate negative impacts from human activities on the environment, and ensure sustainability development. Green technology is also referred to as clean technology or environmental technology which includes technologies, such as IoT, AI, analytics, blockchain, digital twin, security, and cloud, which collect, integrate, and analyze data from various real-time data sources, such as sensors, cameras, and Global Positioning System (GPS).
Green technology, also known as sustainable technology, protects the environment by using various forms of sustainable energy. Some of the best examples of green technologies include solar panels, LED lighting, wind energy, electric vehicles, vertical farming, and composting.
The global Green Technology and Sustainability market size to grow from USD 11.2 billion in 2020 to USD 36.6 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 26.6% during the forecast period. The growing consumer and industrial interest for the use of clean energy resources to conserve environment and increasing use of Radio Frequency Identification sensors across industries are driving the adoption of green technology and sustainability solutions and services in the market.
The blockchain segment is estimated to grow at the highest CAGR: Energy-intensive cryptocurrency mining has caused a spike in carbon emission, and hence blockchain is capable of driving innovation in the field of green technology.
Latest Research
19.31% binary organic solar cell and low non-radiative recombination enabled by non-monotonic intermediate state transition
by Jiehao Fu, Patrick W. K. Fong, Heng Liu, Chieh-Szu Huang, Xinhui Lu, Shirong Lu, Maged Abdelsamie, Tim Kodalle, Carolin M. Sutter-Fella, Yang Yang, Gang Li in Nature Communications
Researchers from The Hong Kong Polytechnic University (PolyU) have achieved a breakthrough power-conversion efficiency (PCE) of 19.31% with organic solar cells (OSCs), also known as polymer solar cells. This remarkable binary OSC efficiency will help enhance applications of these advanced solar energy devices.
The PCE (Power-conversion efficiency), a measure of the power generated from a given solar irradiation, is considered a significant benchmark for the performance of photovoltaics (PVs), or solar panels, in power generation. The improved efficiency of over 19% that was achieved by the PolyU researchers constitutes a record for binary OSCs, which have one donor and one acceptor in the photo-active layer.
Led by Prof. LI Gang, Chair Professor of Energy Conversion Technology and Sir Sze-Yen Chung Endowed Professor in Renewable Energy at PolyU, the research team invented a novel OSC morphology-regulating technique by using 1,3,5-trichlorobenzene as a crystallisation regulator. This new technique boosts OSC efficiency and stability.
The team developed a non-monotonic intermediated state manipulation (ISM) strategy to manipulate the bulk-heterojunction (BHJ) OSC morphology, which simultaneously optimises crystallisation dynamics and energy loss of non-fullerene OSCs. Unlike the strategy of using traditional solvent additives, which is based on excessive molecular aggregation in films, the ISM strategy promotes the formation of more ordered molecular stacking and favourable molecular aggregation. As a result, the PCE was considerably increased and the undesirable non-radiative recombination loss was reduced. Notably, non-radiative recombination lowers the light generation efficiency and increases the heat loss.
The conversion of solar energy to electricity is an essential technology for achieving a sustainable environment. Although OSCs are promising devices that harness solar energy cost-effectively, their efficiency must be improved if they are to be used widely in practical applications.
Non-fullerene acceptors based organic solar cells represent the frontier of research in the field of organic photovoltaics due to both the materials and morphology manipulation innovations. Nevertheless, non-radiative recombination loss suppress and performance boosting are in the centre of organic cell research.
Prof. Li said, “Challenges in research came from the existing additive-based benchmark morphology control methods, which suffer from non-radiative recombination loss, thus lowering the open-circuit voltage due to excessive aggregation.”
The research team took about two years to devise a non-monotonic ISM strategy for increasing the OSC efficiency and lowering the non-radiative recombination loss. The publication of the study promises to galvanise OSC research.
Prof. Li said, “The new finding will make OSC research an exciting field, and this will likely create tremendous opportunities in applications like portable electronics and building-integrated PVs.”
The new door will open when low cost single-junction OSCs can achieve a PCE of over 20%, along with more stable performance and other unique advantages such as flexibility, transparency, stretchability, low weight and tuneable colour.
Prof. Li has been recognised as a Highly Cited Researcher 9 years in a row since 2014, which testifies to his significant impact on global research. His pioneering contributions to research on polymer solar cells since 2005 have brought sustainable influence on printable solar energy development with global recognition.
Prof. Li said, “The latest study shows a record low non-radiative recombination loss of 0.168 eV in a binary OSC with a PCE of over 19%. This is a very encouraging result for the long-standing research on OSCs that I have conducted over the past two decades. We have already achieved better OSC efficiency, and this will subsequently help accelerate the applications of solar energy.”
Efficient photon upconversion enabled by strong coupling between silicon quantum dots and anthracene
by Kefu Wang, R. Peyton Cline, Joseph Schwan, Jacob M. Strain, Sean T. Roberts, Lorenzo Mangolini, Joel D. Eaves, Ming Lee Tang in Nature Chemistry
A group of scientists and engineers that includes researchers from The University of Texas at Austin have created a new class of materials that can absorb low energy light and transform it into higher energy light. The new material is composed of ultra-small silicon nanoparticles and organic molecules closely related to ones utilized in OLED TVs. This new composite efficiently moves electrons between its organic and inorganic components, with applications for more efficient solar panels, more accurate medical imaging and better night vision goggles.
“This process gives us a whole new way of designing materials,” said Sean Roberts, an associate professor of chemistry at UT Austin. “It allows us to take two extremely different substances, silicon and organic molecules, and bond them strongly enough to create not just a mixture, but an entirely new hybrid material with properties that are completely distinct from each of the two components.”
Composites are composed of two or more components that adopt unique properties when combined. For example, composites of carbon fibers and resins find use as lightweight materials for airplane wings, racing cars and many sporting products. In the paper co-authored by Roberts, the inorganic and organic components are combined to show unique interaction with light.
Among those properties are the ability to turn long-wavelength photons — the type found in red light, which tends to travel well though tissue, fog and liquids — into short-wavelength blue or ultraviolet photons, which are the type that usually make sensors work or produce a wide range of chemical reactions. This means the material could prove useful in new technologies as diverse as bioimaging, light-based 3D printing and light sensors that can be used to help self-driving cars travel through fog.
“This concept may be able to create systems that can see in near infrared,” Roberts said. “That can be useful for autonomous vehicles, sensors and night vision systems.”
Taking low energy light and making it higher energy also can potentially help to boost the efficiency of solar cells by allowing them to capture near-infrared light that would normally pass through them. When the technology is optimized, capturing low energy light could reduce the size of solar panels by 30%.
Members of the research team, which includes scientists from the University of California Riverside, University of Colorado Boulder and University of Utah, have been working on light conversion of this type for several years. In a previous paper, they described successfully connecting anthracene, an organic molecule that can emit blue light, with silicon, a material used in solar panels and in many semiconductors. Seeking to amplify the interaction between these materials, the team developed a new method for forging electrically conductive bridges between anthracene and silicon nanocrystals. The resulting strong chemical bond increases the speed with which the two molecules can exchange energy, almost doubling the efficiency in converting lower energy light to higher energy light, compared with the team’s previous breakthrough.
Experimental Investigation of Soapstone and Granite Rocks as Energy-Storage Materials for Concentrated Solar Power Generation and Solar Drying Technology
by Lilian Deusdedit Kakoko, Yusufu Abeid Chande Jande, Thomas Kivevele in ACS Omega
The next generation of sustainable energy technology might be built from some low-tech materials: rocks and the sun. Using a new approach known as concentrated solar power, heat from the sun is stored then used to dry foods or create electricity. A team has found that certain soapstone and granite samples from Tanzania are well suited for storing this solar heat, featuring high energy densities and stability even at high temperatures.
Energy is often stored in large batteries when not needed, but these can be expensive and require lots of resources to manufacture. A lower-tech alternative is thermal energy storage (TES), which collects energy as heat in a liquid or solid, such as water, oil or rock. When released, the heat can power a generator to produce electricity. Rocks such as granite and soapstone are specifically formed under high heat and found across the globe, which might make them favorable TES materials. However, their properties can vary greatly based on where in the world they were formed, possibly making some samples better than others. In Tanzania, the Craton and Usagaran geological belts meet, and both contain granite and soapstone. So, Lilian Deusdedit Kakoko, Yusufu Abeid Chande Jande and Thomas Kivevele from Nelson Mandela African Institution of Science and Technology and Ardhi University wanted to investigate the properties of soapstone and granite found in each of these belts.
The team collected several rock samples from the belts and analyzed them. The granite samples contained a large amount of silicon oxides, which added strength. However, the Craton granite contained other compounds, including muscovite, which are susceptible to dehydration and could make the rock unstable at high temperatures. Magnesite was found in the soapstone, which conferred a high density and thermal capacity. When heated to temperatures over 1800 degrees Fahrenheit, both soapstone samples and the Usagaran granite had no visible cracks, but the Craton granite fell apart. Additionally, the soapstone was more likely to release its stored heat than the granite. In all, the Craton soapstone had the best performance as a TES, able to absorb, store and transmit heat effectively while maintaining good chemical stability and mechanical strength. However, the other rocks might be better suited for a lower-energy TES application, such a solar dryer. The researchers say that though further experiments are needed, these samples show good promise in being a sustainable energy storage material.
The growing metaverse sector can reduce greenhouse gas emissions by 10 Gt CO2e in the united states by 2050
by Ning Zhao, Fengqi You in Energy & Environmental Science
For many technology enthusiasts, the metaverse has the potential to transform almost every facet of human life, from work to education to entertainment. Now, new Cornell University research shows it could have environmental benefits, too.
Researchers find the metaverse could lower global surface temperature by up to 0.02 degrees Celsius before the end of the century. They used AI-based modeling to analyze data from key sectors — technology, energy, environment and business — to anticipate the growth of metaverse usage and the impact of its most promising applications: remote work, virtual traveling, distance learning, gaming and non-fungible tokens (NFTs).
The researchers projected metaverse expansion through 2050 along three different trajectories — slow, nominal and fast — and they looked to previous technologies, such as television, the internet and the iPhone, for insight into how quickly that adoption might occur. They also factored in the amount of energy that increasing usage would consume. The modeling suggested that within 30 years, the technology would be adopted by more than 90% of the population.
“One thing that did surprise us is that this metaverse is going to grow much quicker than what we expected,” said Fengqi You, professor in energy systems engineering and the paper’s senior author. “Look at earlier technologies — TV, for instance. It took decades to be eventually adopted by everyone. Now we are really in an age of technology explosion. Think of our smartphones. They grew very fast.”
Currently, two of the biggest industry drivers of metaverse development are Meta and Microsoft, both of which contributed to the study. Meta has been focusing on individual experiences, such as gaming, while Microsoft specializes in business solutions, including remote conferencing and distance learning. Limiting business travel would generate the largest environmental benefit, according to You.
“Think about the decarbonization of our transportation sector,” he said. “Electric vehicles work, but you can’t drive a car to London or Tokyo. Do I really have to fly to Singapore for a conference tomorrow? That will be an interesting decision-making point for some stakeholders to consider as we move forward with these technologies with human-machine interface in a 3D virtual world.”
The paper notes that by 2050 the metaverse industry could potentially lower greenhouse gas emissions by 10 gigatons; lower atmospheric carbon dioxide concentration by 4.0 parts per million; decrease effective radiative forcing by 0.035 watts per square meter; and lower total domestic energy consumption by 92 EJ, a reduction that surpasses the annual nationwide energy consumption of all end-use sectors in previous years.
These findings could help policymakers understand how metaverse industry growth can accelerate progress towards achieving net-zero emissions targets and spur more flexible decarbonization strategies. Metaverse-based remote working, distance learning and virtual tourism could be promoted to improve air quality. In addition to alleviating air pollutant emissions, the reduction of transportation and commercial energy usage could help transform the way energy is distributed, with more energy supply going towards the residential sector.
“This mechanism is going to help, but in the end, it is going to help lower the global surface temperature by up to 0.02 degrees,” You said. “There are so many sectors in this economy. You cannot count on the metaverse to do everything. But it could do a little bit if we leverage it in a reasonable way.”
Using earth abundant materials for long duration energy storage: electro-chemical and thermo-chemical cycling of bicarbonate/formate
by Oliver Y. Gutiérrez, Katarzyna Grubel, Jotheeswari Kothandaraman, Juan A. Lopez-Ruiz, Kriston P. Brooks, Mark E. Bowden, Tom Autrey in Green Chemistry
In a world of continuously warmer temperatures, a growing consensus demands that energy sources have zero, or next-to-zero, carbon emissions. That means growing beyond coal, oil, and natural gas by getting more energy from renewable sources. One of the most promising renewable energy carriers is clean hydrogen, which is produced without fossil fuels.
It’s a promising idea because the most abundant element in the universe is hydrogen, found in 75 percent of all matter. Moreover, a hydrogen molecule has two paired atoms — Gemini twins that are both non-toxic and highly combustible. Hydrogen’s combustive potential makes it an attractive subject for energy researchers around the world. At Pacific Northwest National Laboratory (PNNL), a team is investigating hydrogen as a medium for storing and releasing energy, largely by cracking its chemical bonds. Much of their work is linked to the Hydrogen Materials-Advanced Research consortium (HyMARC) at the Department of Energy (DOE).
One PNNL research focus relates to optimizing hydrogen storage, a stubborn issue. To date, there is no completely safe, cost-effective, and energy-efficient way to store hydrogen at large scales. PNNL researchers recently coauthored a paper that investigates a baking soda solution as a means of storing hydrogen. The study has already been dubbed a “hot paper”. That means that it has had a lot of clicks showing interest. The new paper’s two main authors are chemist and PNNL Laboratory Fellow Thomas Autrey and his colleague Oliver Gutiérrez, an expert in making chemical reactions speedy and cost-effective.
“You have to be a little creative,” said Autrey, who is amused at how common, cheap, and mild baking soda is as a potential answer to a big problem. “Not every chemical is going to be efficient at storing hydrogen. You have to work with what Mother Nature gives you.”
Autrey, Gutiérrez, and others at PNNL see long-duration energy storage as the key to hydrogen’s future as a carrier of renewable energy. Current battery technology is designed for several hours of storage. In a renewable energy grid, batteries can handle about 80 percent of storage needs.
But “the last 20 percent will take unique approaches,” said Autrey. “We will want to store the excess energy to be prepared for Dunkelflaute.”
That’s a German word describing conditions without enough solar and wind energy potential. During the dark, windless periods of Dunkelflaute, grids need a way to store energy for more than just several hours. Seasonal storage capability like this is one of hydrogen’s attractions. So is the fact that hydrogen storage can happen anywhere that it is “geographically agnostic,” as experts say. Hydropower, for example, requires differences in elevation to store excess water to make power. Hydrogen storage requires no special conditions related to geography. In addition, said Autrey, as scales get larger, hydrogen gets more economical. It is cheaper to buy a few additional hydrogen storage tanks than to buy a lot of batteries.
Clean hydrogen has great promise as an energy source. A process called electrolysis, for instance, can split water into hydrogen and oxygen. In the best of worlds, the power for electrolysis would come from renewable energy sources, including solar, wind, and geothermal. However, there is one stubborn challenge: to produce hydrogen more cheaply.
To address that, in 2021 the DOE announced its Energy Earthshots initiative, a series of six steps to underwrite breakthroughs in clean-energy technology. Introduced first was the Hydrogen Shot, a quest to reduce the cost of hydrogen to from $5 to $1 per kilogram in a decade — an 80 percent reduction. Beyond getting clean hydrogen production costs down, “you have to figure out how to move and store it,” said Autrey, which are steps that can send prices back up. But finding the ideal medium for hydrogen storage has been elusive.
Hydrogen can be compressed into a gas, but that requires very high pressures — up to 10,000 pounds per square inch. A safe storage tank would need walls of very thick steel or expensive space-grade carbon fiber. How about cryogenic liquid hydrogen? This is a proven storage medium but requires getting and keeping something so cold that peripheral energy costs are significant. What seems to hold the most promise are molecules that are liquids, optimized to store and release hydrogen. Jamie Holladay, a sustainable energy expert, recently directed PNNL-led research on simpler and more efficient strategies for liquefying hydrogen. Using such liquids as a storage medium have the advantage of keeping existing energy infrastructure in place, including pipelines, trucks, trains, and taker ships, said Gutierrez.
Want to bake cookies? Or store hydrogen energy? Baking soda could be the ticket. This mild, cheap sodium salt of bicarbonate is non-toxic and Earth-abundant. Not baking soda exactly. The PNNL team is investigating the hydrogen energy storage properties of the long-studied bicarbonate-formate cycle. (Formate is a safe, mild liquid organic molecule.)
Here’s how it works: Solutions of formate ions (hydrogen and carbon dioxide) in water carry hydrogen based on non-corrosive alkali metal formate. The ions react with water in the presence of a catalyst. That reaction makes hydrogen and bicarbonates the “baking soda” Autrey admires for its absence of environmental impacts. With the right mild tweaks in pressure, the bicarbonate-formate cycle can be reversed. That provides an on-off switch for an aqueous solution that can alternately store or release hydrogen.
Before baking soda, the PNNL hydrogen storage team looked at ethanol as a liquid organic hydrogen carrier, the industry’s blanket term for storage and transport media. In tandem, they developed a catalyst that releases the hydrogen. Catalysts are designer additives that speed the processes used to make and break chemical bonds in an energy-efficient way.
Treatment of brackish water for fossil power plant cooling
by Zitao Wu, Haibo Zhai, Eric J. Grol, Chad M. Able, Nicholas S. Siefert in Nature Water
A new analysis led by a University of Wyoming researcher shows that brackish or salty groundwater has the potential to replace fresh water to cool coal- and natural gas-fired power plants and strengthen resilience in the energy infrastructure, although there’s a cost associated with doing so.
With freshwater supplies threatened due to drought, climate change and rapid socioeconomic growth, water competition is increasing between the electric power sector and other sectors. While transitioning to a low-carbon energy future, decarbonization of fossil fuel-fired power plants by carbon capture and storage would significantly increase water consumption and exacerbate water competition. Water challenges drive power plant operators to explore alternative water sources.
“Nontraditional water sources can be deployed to help cope with climate-induced water risks and tackle the increasing water demand for decarbonization of fossil fuel-fired power plants,” wrote the research team, led by Haibo Zhai, UW’s Roy and Caryl Cline Distinguished Chair in the College of Engineering and Physical Sciences. “Treatment of brackish groundwater for thermoelectric generation cooling can help alleviate potential competition for freshwater resources among various sectors in water-stressed regions.”
Zhai’s UW Ph.D. student, Zitao Wu is the lead author of the paper. Other contributors are from the National Energy Technology Laboratory in Pittsburgh, Pa. This journal publishes the best research on the evolving relation between water and society. It’s the second paper of a multiyear project funded by the U.S. Department of Energy; the first paper, published last year in the journal Applied Energy, examined the possibility of switching from water cooling towers to dry cooling systems at fossil fuel-fired plants.
Removing excess dissolved salts and minerals from brackish water can itself be energy intensive and produce concentrated brines requiring disposal. A method called zero liquid discharge minimizes environmental impacts of desalination but is particularly costly.
The researchers examined the technical and economic feasibility of multiple desalination processes. They also estimated how much fresh water would be saved as a result of treating brackish water for power plant cooling, and they evaluated the cost-effectiveness of brackish water treatment retrofits — and the impact on the net generating capacity of power plants. They concluded that retrofitting power plants to treat brackish groundwater could nearly eliminate the use of fresh water but would increase the cost of electricity generation by 8 percent to 10 percent.
“Our study reveals trade-offs in freshwater savings, cost and generating capacity shortfalls from desalination deployment,” Wu says.
The researchers call for further development of technologies to treat brackish water, along with exploration of using other nontraditional water sources for cooling of power plants. Those include treated municipal wastewater, as well as water produced from oil and gas extraction and carbon dioxide storage reservoirs.
The trade-offs identified for various nontraditional water sources will fill knowledge gaps to better inform water-for-energy decisions and management, the researchers say.
Evaluation of alternative power-to-chemical pathways for renewable energy exports
by Muhammad Aadil Rasool, Kaveh Khalilpour, Ahmad Rafiee, Iftekhar Karimi, Reinhard Madlener in Energy Conversion and Management
A team of researchers has created a new supply chain model which could empower the international hydrogen renewable energy industry.
Hydrogen has been touted as the clean fuel of the future; it can be generated from water and produces zero carbon emissions. However, it is currently expensive to transport over long distances, and currently no infrastructure is in place to do so.
The new supply chain model, created by researchers in Australia, Singapore and Germany, successfully guides the development of international transport of hydrogen and its embodied energy. Associate Professor Kaveh Khalilpour, from the University of Technology Sydney (UTS) and lead of the report, said supply chain design is critical for making hydrogen economic.
“We looked at the renewable hydrogen export from Australia to Singapore, Japan, and Germany. Surprisingly, the analysis revealed that it matters whether the goal is to export ‘hydrogen the atom’ or ‘hydrogen the energy’. Each choice leads to a different supply chain system.
“Therefore, a thorough understanding of the whole system is necessary for correct decision making,” said Associate Professor Khalilpour.
“The abundance of renewable energy resources in Australia, as well as its stable economy, means the country can attract investments in building these green value chains in our region and even as far away as Europe.”
Hydrogen is expected to help diversify Australia’s renewable energy resource beyond solar and wind power. This is seen as critical to the country’s energy security, as well as necessary for climate change mitigation.
“Hydrogen is just an energy carrier, i.e. not a primary energy source, and thus only a means to an end for transporting renewable energy from one place to another.
“The key business question around the emerging hydrogen economy is whether commodities such as green hydrogen, methanol or ammonia can be exported profitably and competitively also over long distances and across the oceans, thus bringing green energy to other places in the world.
“If this is so, this will also have major international energy and climate policy implications,” said Professor Reinhard Madlener, co-lead of the project, from RWTH Aachen University, Germany.
“Our model suggests that methanol shows great promise as a chemical carrier for exporting renewable energy from Australia at low costs,” said Professor Iftekhar Karimi, from the National University of Singapore, and co-lead of the project.
La- and Mn-doped cobalt spinel oxygen evolution catalyst for proton exchange membrane electrolysis
by Lina Chong, Guoping Gao, Jianguo Wen, Haixia Li, Haiping Xu, Zach Green, Joshua D. Sugar, A. Jeremy Kropf, Wenqian Xu, Xiao-Min Lin, Hui Xu, Lin-Wang Wang, Di-Jia Liu in Science
A plentiful supply of clean energy is lurking in plain sight. It is the hydrogen we can extract from water (H2O) using renewable energy. Scientists are seeking low-cost methods for producing clean hydrogen from water to replace fossil fuels, as part of the quest to combat climate change.
Hydrogen can power vehicles while emitting nothing but water. Hydrogen is also an important chemical for many industrial processes, most notably in steel making and ammonia production. Using cleaner hydrogen is highly desirable in those industries. A multi-institutional team led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory has developed a low-cost catalyst for a process that yields clean hydrogen from water. Other contributors include DOE’s Sandia National Laboratories and Lawrence Berkeley National Laboratory, as well as Giner Inc.
“A process called electrolysis produces hydrogen and oxygen from water and has been around for more than a century,” said Di-Jia Liu, senior chemist at Argonne. He also holds a joint appointment in the Pritzker School of Molecular Engineering at the University of Chicago.
Proton exchange membrane (PEM) electrolyzers represent a new generation of technology for this process. They can split water into hydrogen and oxygen with higher efficiency at near room temperature. The reduced energy demand makes them an ideal choice for producing clean hydrogen by using renewable but intermittent sources, such as solar and wind.
This electrolyzer runs with separate catalysts for each of its electrodes (cathode and anode). The cathode catalyst yields hydrogen, while the anode catalyst forms oxygen. A problem is that the anode catalyst uses iridium, which has a current market price of around $5,000 per ounce. The lack of supply and high cost of iridium pose a major barrier for widespread adoption of PEM electrolyzers.
The main ingredient in the new catalyst is cobalt, which is substantially cheaper than iridium.
“We sought to develop a low-cost anode catalyst in a PEM electrolyzer that generates hydrogen at high throughput while consuming minimal energy,” Liu said. “By using the cobalt-based catalyst prepared by our method, one could remove the main bottleneck of cost to producing clean hydrogen in an electrolyzer.”
Giner Inc., a leading research and development company working toward commercialization of electrolyzers and fuel cells, evaluated the new catalyst using its PEM electrolyzer test stations under industrial operating conditions. The performance and durability far exceeded that of competitors’ catalysts.
Important to further advancing the catalyst performance is understanding the reaction mechanism at the atomic scale under electrolyzer operating conditions. The team deciphered critical structural changes that occur in the catalyst under operating conditions by using X-ray analyses at the Advanced Photon Source (APS) at Argonne. They also identified key catalyst features using electron microscopy at Sandia Labs and at Argonne’s Center for Nanoscale Materials (CNM). The APS and CNM are both DOE Office of Science user facilities.
“We imaged the atomic structure on the surface of the new catalyst at various stages of preparation,” said Jianguo Wen, an Argonne materials scientist.
In addition, computational modeling at Berkeley Lab revealed important insights into the catalyst’s durability under reaction conditions. The team’s achievement is a step forward in DOE’s Hydrogen Energy Earthshot initiative, which mimics the U.S. space program’s “Moon Shot” of the 1960s. Its ambitious goal is to lower the cost for green hydrogen production to one dollar per kilogram in a decade. Production of green hydrogen at that cost could reshape the nation’s economy. Applications include the electric grid, manufacturing, transportation and residential and commercial heating.
“More generally, our results establish a promising path forward in replacing catalysts made from expensive precious metals with elements that are much less expensive and more abundant,” Liu noted.
Catalytic disconnection of C–O bonds in epoxy resins and composites
by Alexander Ahrens, Andreas Bonde, Hongwei Sun, Nina Kølln Wittig, Hans Christian D. Hammershøj, Gabriel Martins Ferreira Batista, Andreas Sommerfeldt, Simon Frølich, Henrik Birkedal, Troels Skrydstrup in Nature
The new chemical process is not limited to wind turbine blades but works on many different so-called fibre-reinforced epoxy composites, including some materials that are reinforced with especially costly carbon fibres.
Thus, the process can contribute to establishing a potential circular economy in the wind turbine, aerospace, automotive and space industries, where these reinforced composites, due to their light weight and long durability, are used for load-bearing structures. Being designed to last, the durability of the blades poses an environmental challenge. Wind turbine blades mostly end up at waste landfills when they are decommissioned, because they are extremely difficult to break down. If no solution is found, we will have accumulated 43 million tonnes of wind turbine blade waste globally by 2050.
The newly discovered process is a proof-of-concept of a recycling strategy that can be applied to the vast majority of both existing wind turbine blades and those presently in production, as well as other epoxy-based materials. Aarhus University, together with the Danish Technological Institute, have filed a patent application for the process. Specifically, the researchers have shown that by using a ruthenium-based catalyst and the solvents isopropanol and toluene, they can separate the epoxy matrix and release one of the epoxy polymer’s original building blocks, bisphenol A (BPA), and fully intact glass fibres in a single process.
However, the method is not immediately scalable yet, as the catalytic system is not efficient enough for industrial implementation — and ruthenium is a rare and expensive metal. Therefore, the scientists from Aarhus University are continuing their work on improving this methodology.
“Nevertheless, we see it as a significant breakthrough for the development of durable technologies that can create a circular economy for epoxy-based materials. This is the first publication of a chemical process that can selectively disassemble an epoxy composite and isolate one of the most important building blocks of the epoxy polymer as well as the glass or carbon fibres without damaging the latter in the process,” says Troels Skrydstrup, one of the lead authors of the study.
Polyacrylonitrile nanofibrous membrane composited with zeolite imidazole skeleton-8 and silver nanoclusters for efficient antibacterial and emulsion separation
by Huaxiang Chen, Hao Zhou, Mingchao Chen, Yan Quan, Chenglong Wang, Yujie Gao, Jindan Wu in Biointerphases
When oil contaminates water, it creates a film that reduces oxygen levels and introduces toxic substances. This can lead to the death of aquatic plants and animals, contaminate soil, and ultimately threaten human health.
Separating oil from polluted water is therefore of great importance. Current methods can be expensive and challenging, and some may introduce further pollutants into the system. For example, membrane materials can act as a barrier to intercept oil, but their efficiency is low and they aren’t suited for long-term use. Researchers in China developed a fabrication method to increase the efficacy and longevity of membrane separation technology. The technology is greater than 99% effective at separating a petroleum ether-in-water emulsion.
The team created a nanofibrous membrane with electrospinning, in which a liquid polymer droplet is electrified and stretched to make fibers. They increased the roughness of the membrane surface by loading it with silver nanoparticles. In water, this rough surface promotes a stable layer of water, which acts as a barrier to prevent oil droplets from entering the membrane.
“This hydration layer efficiently impedes the passage of oil droplets, reducing membrane pollution and enhancing the composite membrane’s permeability and separation efficiency,” said author Jindan Wu.
Silver nanoparticles also enhance the membrane’s antibacterial properties. Incorporating them minimizes the risk of membrane corrosion that can be caused by microorganisms.
“We have discovered that the membrane’s surface roughness and hydration layer strength are critical factors that impact its separation performance and anti-fouling ability,” said Wu. “This concept of depositing particles on nanofibrous membranes also has potential for broad applications with other materials.”
The current output capabilities of this fabrication method are relatively low. However, the group hopes developing such materials will contribute to a comprehensive solution for treating water pollution.
“Water pollution is caused by multiple sources, and oily wastewater is just one of them,” said Wu. “It is of vital importance to develop materials that can treat for dyes, heavy metals, and bacteria present in water.”
MISC
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