GT/ Eco-friendly way to generate power from waste wood
Energy & green technology biweekly vol.64, 10th February — 29th February
TL;DR
- Researchers unveil a sustainable method to convert waste heat into electricity using Irish wood products, aiming to minimize costs and environmental impact.
- A research team, having previously synthesized fumaric acid efficiently, now doubles its production using a new photosensitizer and artificial photosynthesis technology, reducing carbon dioxide emissions and contributing to biodegradable plastics.
- A novel ligand exchange technique is introduced, ensuring exceptional stability and suppressing defects in perovskite quantum dots for solar cells, a breakthrough in improving efficiency.
- Physicists use complex simulations to design significantly more efficient solar cells, incorporating a thin layer of organic material called tetracene.
- A new study finds that introducing a simple, renewable chemical to the pretreatment step can finally make next-generation biofuel production both cost-effective and carbon neutral.
- Engineers develop an efficient method to convert carbon dioxide into valuable products, offering a solution to climate change concerns.
- A biohybrid catalyst is introduced to oxidize polystyrene microparticles, making the widespread and non-recyclable plastic more degradable, using a specially constructed ‘anchor peptide’ and a cobalt complex.
- Scientists report an electrochemical method to efficiently release hydrogen stored in hydrogen boride sheets, suggesting a cleaner and more sustainable fuel storage and transport solution.
- Researchers identify the optimal length for a yarn-shaped supercapacitor, a threadlike energy storage technology, to achieve the highest and most efficient energy flow per unit length.
- Using cryo-electron microscopy, researchers unveil the structure of light-harvesting complexes in purple sulfur bacteria, explaining their ability to photosynthesize in low-calcium environments.
- 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.
Latest Research
Lignin‐Derived Ionic Conducting Membranes for Low‐Grade Thermal Energy Harvesting
by Muhammad Muddasar, Mohammad Ali Nasiri, Andres Cantarero, Clara Gómez, Mario Culebras, Maurice N. Collins in Advanced Functional Materials
A new study by researchers at University of Limerick in Ireland has revealed a sustainable method of efficiently converting waste heat into electricity using Irish wood products, while minimising costs and environmental impact.
The groundbreaking study, led by researchers at UL in collaboration with colleagues at the University of Valencia, has demonstrated a method of generating electricity using low-grade heat recovered from lignin-derived membranes. Lignin, typically overlooked, is a sustainable byproduct derived from wood in paper and pulp production.
The study shows that these membranes can convert waste heat into electricity by utilising the movement of charged atoms (ions) within the material. This is a significant advancement as previous studies had only demonstrated this technology using cellulose from natural wood, and the new UL research has successfully applied it to lignin from waste wood — contributing to a more circular and sustainable economy as a result.
Low-grade heat refers to waste heat generated at temperatures below 200 degrees Celsius. In industrial processes, 66% of the waste heat falls into this category, highlighting the potential of this breakthrough for developing sustainable heat-to-electricity applications.
Professor Maurice N Collins, Professor of Materials Science in UL’s School of Engineering and Principal Investigator at the Bernal Institute who supervised the study, explained: “Low-grade heat comes from various sources like waste heat in industries, heat losses in insulating systems, ocean thermal gradients, biomass fermentation, and solar heat. “Despite its potential, utilising low-grade thermal energy in energy harvesting applications has been challenging due to the lack of cost-effective technologies.
“Our research explores the use of ionic thermoelectric membranes made from lignin, an underutilised by-product in the paper and pulp industry, offering a sustainable solution.”
Lead author Muhammad Muddasar, a NXTGENWOOD PhD student based at the Bernal Institute, explained: “We have developed the first lignin-based membrane for ionic thermoelectric energy harvesting. “Our membrane is lightweight, easy to synthesise, and biocompatible, making it suitable for various applications, including thermal energy harvesting, temperature sensing, and biomedical sensors for health monitoring.”
The UL researcher’s work on the NXTGENWOOD project comes under the umbrella of the Science Federation Ireland-funded Centre for Advanced Materials and BioEngineering Research (AMBER). The project is dedicated to developing new value-added applications from Irish wood.
Professor Collins added of the environmental potential of the research taking place at UL: “While there is still room for further development in heat-to-electricity conversion applications, the study demonstrates that abundantly available lignin can successfully contribute to low-grade thermal energy harvesting, especially in scenarios where sustainability and cost-effectiveness are crucial.”
An effective visible-light driven fumarate production from gaseous CO2 and pyruvate by the cationic zinc porphyrin-based photocatalytic system with dual biocatalysts
by Mika Takeuchi, Yutaka Amao in Dalton Transactions
A research team from Osaka Metropolitan University that had previously succeeded in synthesizing fumaric acid using bicarbonate and pyruvic acid, and carbon dioxide collected directly from the gas phase as one of the raw materials, has now created a new photosensitizer and developed a new artificial photosynthesis technology, effectively doubling the yield of fumaric acid production compared to the previous method. The results of this research are expected to reduce carbon dioxide emissions and provide an innovative way to produce biodegradable plastics while reusing waste resources.
Amid growing global concern over climate change and plastic pollution, researchers at Osaka Metropolitan University are making great strides in the sustainable production of fumaric acid — a component of biodegradable plastics such as polybutylene succinate, which is commonly used for food packaging. The researchers have managed to efficiently produce fumaric acid, which is traditionally derived from petroleum, using renewable resources, carbon dioxide, and biomass-derived compounds.
In a previous study, a research team led by Professor Yutaka Amao of the Research Center for Artificial Photosynthesis at Osaka Metropolitan University demonstrated the synthesis of fumaric acid from bicarbonate and pyruvic acid, a biomass-derived compound, using solar energy. They also succeeded in producing fumaric acid using carbon dioxide obtained directly from the gas phase as a raw material. However, the yield in the production of fumaric acid remained low.
In their latest research, the researchers have now developed a new photosensitizer and further advanced an artificial photosynthesis technique that doubles the yield of fumaric acid compared to conventional methods.
“This is an extremely important advancement for the complex bio/photocatalyst system. It is a valuable step forward in our quest to synthesize fumaric acid from renewable energy sources with even higher yields, steering us toward a more sustainable future,” said Professor Amao.
Alkyl ammonium iodide-based ligand exchange strategy for high-efficiency organic-cation perovskite quantum dot solar cells
by Havid Aqoma, Sang-Hak Lee, Imil Fadli Imran, Jin-Ha Hwang, Su-Ho Lee, Sung-Yeon Jang in Nature Energy
A groundbreaking research breakthrough in solar energy has propelled the development of the world’s most efficient quantum dot (QD) solar cell, marking a significant leap towards the commercialization of next-generation solar cells. This cutting-edge QD solution and device have demonstrated exceptional performance, retaining their efficiency even after long-term storage. Led by Professor Sung-Yeon Jang from the School of Energy and Chemical Engineering at UNIST, a team of researchers has unveiled a novel ligand exchange technique. This innovative approach enables the synthesis of organic cation-based perovskite quantum dots (PQDs), ensuring exceptional stability while suppressing internal defects in the photoactive layer of solar cells.
“Our developed technology has achieved an impressive 18.1% efficiency in QD solar cells,” stated Professor Jang. “This remarkable achievement represents the highest efficiency among quantum dot solar cells recognized by the National Renewable Energy Laboratory (NREL) in the United States.”
The increasing interest in related fields is evident, as last year, three scientists who discovered and developed QDs, as advanced nanotechnology products, were awarded the Nobel Prize in Chemistry.
QDs are semiconducting nanocrystals with typical dimensions ranging from several to tens of nanometers, capable of controlling photoelectric properties based on their particle size. PQDs, in particular, have garnered significant attention from researchers due to their outstanding photoelectric properties. Furthermore, their manufacturing process involves simple spraying or application to a solvent, eliminating the need for the growth process on substrates. This streamlined approach allows for high-quality production in various manufacturing environments. However, the practical use of QDs as solar cells necessitates a technology that reduces the distance between QDs through ligand exchange, a process that binds a large molecule, such as a ligand receptor, to the surface of a QD. Organic PQDs face notable challenges, including defects in their crystals and surfaces during the substitution process. As a result, inorganic PQDs with limited efficiency of up to 16% have been predominantly utilized as materials for solar cells.
In this study, the research team employed an alkyl ammonium iodide-based ligand exchange strategy, effectively substituting ligands for organic PQDs with excellent solar utilization. This breakthrough enables the creation of a photoactive layer of QDs for solar cells with high substitution efficiency and controlled defects. Consequently, the efficiency of organic PQDs, previously limited to 13% using existing ligand substitution technology, has been significantly improved to 18.1%. Moreover, these solar cells demonstrate exceptional stability, maintaining their performance even after long-term storage for over two years. The newly-developed organic PQD solar cells exhibit both high efficiency and stability simultaneously.
“Previous research on QD solar cells predominantly employed inorganic PQDs,” remarked Sang-Hak Lee, the first author of the study. “Through this study, we have demonstrated the potential by addressing the challenges associated with organic PQDs, which have proven difficult to utilize.”
“This study presents a new direction for the ligand exchange method in organic PQDs, serving as a catalyst to revolutionize the field of QD solar cell material research in the future,” commented Professor Jang.
Defect-Assisted Exciton Transfer across the Tetracene-Si(111):H Interface
by Marvin Krenz, Uwe Gerstmann, Wolf Gero Schmidt in Physical Review Letters
Physicists at Paderborn University have used complex computer simulations to develop a new design for significantly more efficient solar cells than previously available. A thin layer of organic material, known as tetracene, is responsible for the increase in efficiency.
“The annual energy of solar radiation on Earth amounts to over one trillion kilowatt hours and thus exceeds the global energy demand by more than 5000 times. Photovoltaics, i.e. the generation of electricity from sunlight, therefore offers a large and still largely untapped potential for the supply of clean and renewable energy. Silicon solar cells used for this purpose currently dominate the market, but have efficiency limits,” explains Prof Dr Wolf Gero Schmidt, physicist and Dean of the Faculty of Natural Sciences at Paderborn University. One reason for this is that some of the energy from short-wave radiation is not converted into electricity, but into unwanted heat.
Schmidt explains: “In order to increase the efficiency, the silicon solar cell can be provided with an organic layer, for example made from the semiconductor tetracene. Short-wave light is absorbed in this layer and converted into high-energy electronic excitations, so-called excitons. These excitons decay in the tetracene into two low-energy excitations. If these excitations can be successfully transferred to the silicon solar cell, they can be efficiently converted into electricity and increase the overall yield of usable energy.”
The excitation transfer of tetracene into silicon is being investigated by Schmidt’s team using complex computer simulations at the Paderborn Center for Parallel Computing (PC2), the university’s high-performance computing centre.
A decisive breakthrough has now been achieved: in a joint study with Dr Marvin Krenz and Prof. Dr Uwe Gerstmann, both also from Paderborn University, the scientists have shown that special defects in the form of unsaturated chemical bonds at the interface between the tetracene film and the solar cell dramatically accelerate the exciton transfer.
Schmidt: “Such defects occur during the desorption of hydrogen and cause electronic interface states with fluctuating energy. These fluctuations transport the electronic excitations from the tetracene into the silicon like a lift.”
Such “defects” in solar cells are actually associated with energy losses. This makes the results of the trio of physicists all the more astonishing: “In the case of the silicon tetracene interface, the defects are essential for the rapid energy transfer. The results of our computer simulations are truly surprising. They also provide precise indications for the design of a new type of solar cell with significantly increased efficiency,” the physicist states.
Economics and global warming potential of a commercial-scale delignifying biorefinery based on co-solvent enhanced lignocellulosic fractionation to produce alcohols, sustainable aviation fuels, and co-products from biomass
by Bruno Colling Klein, Brent Scheidemantle, Rebecca J. Hanes, Andrew W. Bartling, Nicholas J. Grundl, Robin J. Clark, Mary J. Biddy, Ling Tao, Cong T. Trinh, Adam M. Guss, Charles E. Wyman, Arthur J. Ragauskas, Erin G. Webb, Brian H. Davison, Charles M. Cai in Energy & Environmental Science
When it comes to making fuel from plants, the first step has always been the hardest — breaking down the plant matter. A new study finds that introducing a simple, renewable chemical to the pretreatment step can finally make next-generation biofuel production both cost-effective and carbon neutral.
For biofuels to compete with petroleum, biorefinery operations must be designed to better utilize lignin. Lignin is one of the main components of plant cell walls. It provides plants with greater structural integrity and resiliency from microbial attacks. However, these natural properties of lignin also make it difficult to extract and utilize from the plant matter, also known as biomass.
“Lignin utilization is the gateway to making what you want out of biomass in the most economical and environmentally friendly way possible,” said UC Riverside Associate Research Professor Charles Cai. “Designing a process that can better utilize both the lignin and sugars found in biomass is one of the most exciting technical challenges in this field.”
To overcome the lignin hurdle, Cai invented CELF, which stands for co-solvent enhanced lignocellulosic fractionation. It is an innovative biomass pretreatment technology.
“CELF uses tetrahydrofuran or THF to supplement water and dilute acid during biomass pretreatment. It improves overall efficiency and adds lignin extraction capabilities,” Cai said. “Best of all, THF itself can be made from biomass sugars.”
A landmark Energy & Environmental Science paper details the degree to which a CELF biorefinery offers economic and environmental benefits over both petroleum-based fuels and earlier biofuel production methods. The paper is a collaboration between Cai’s research team at UCR, the Center for Bioenergy Innovation managed by Oak Ridge National Laboratories, and the National Renewable Energy Laboratory, with funding provided by the U.S. Department of Energy’s Office of Science. In it, the researchers consider two main variables: what kind of biomass is most ideal and what to do with the lignin once it’s been extracted.
First-generation biofuel operations use food crops like corn, soy, and sugarcane as raw materials, or feedstocks. Because these feedstocks divert land and water away from food production, using themfor biofuels is not ideal. Second-generation operations use non-edible plant biomass as feedstocks. An example of biomass feedstocks includes wood residues from milling operations, sugarcane bagasse, or corn stover, all of which are abundant low-cost byproducts of forestry and agricultural operations.
According to the Department of Energy, up to a billion tons per year of biomass could be made available for the manufacture of biofuels and bioproducts in the US alone, capable of displacing 30% of our petroleum consumption while also creating new domestic jobs. Because a CELF biorefinery can more fully utilize plant matter than earlier second-generation methods, the researchers found that a heavier, denser feedstock like hardwood poplar is preferable over less carbon-dense corn stover for yielding greater economic and environmental benefits.
Using poplar in a CELF biorefinery, the researchers demonstrate that sustainable aviation fuel could be made at a break-even price as low as $3.15 per gallon of gasoline equivalent. The current average cost for a gallon of jet fuel in the U.S. is $5.96. The U.S. government issues credits for biofuel production in the form of renewable identification number credits, a subsidy meant to bolster domestic biofuel production. The tier of these credits issued for second-generation biofuels, the D3 tier, is typically traded at $1 per gallon or higher. At this price per credit, the paper demonstrates that one can expect a rate of return of over 20% from the operation.
“Spending a little more for a more carbon-rich feedstock like poplar still yields more economic benefits than a cheaper feedstock like corn stover, because you can make more fuel and chemicals from it,” Cai said.
The paper also illustrates how lignin utilization can positively contribute to overall biorefinery economics while keeping the carbon footprint as low as possible. In older biorefinery models, where biomass is cooked in water and acid, the lignin is mostly unusable for more than its heating value.
“The older models would elect to burn the lignin to supplement heat and energy for these biorefineries because they could mostly only leverage the sugars in the biomass — a costly proposition that leaves a lot of value off the table,” said Cai.
In addition to better lignin utilization, the CELF biorefinery model also proposes to produce renewable chemicals. These chemicals could be used as building blocks for bioplastics and food and drink flavoring compounds. These chemicals take up some of the carbon in the plant biomass that would not get released back into the atmosphere as CO2.
“Adding THF helps reduce the energy cost of pretreatment and helps isolate lignin, so you wouldn’t have to burn it anymore. On top of that, we can make renewable chemicals that help us achieve a near-zero global warming potential,” Cai said. “I think this moves the needle from Gen 2 biofuels to Gen 2+.”
In light of the team’s recent successes, the Department of Energy’s Bioenergy Technology Office has awarded the researchers a $2 million grant to build a small-scale CELF pilot plant at UCR. Cai hopes that demonstrating the pilot plant will lead to larger-scale investment in the technology, as harnessing energy from fossil fuels adds to global warming and hurts the planet.
“I began this work more than a decade ago because I wanted to make an impact. I wanted to find a viable alternative to fossil fuels and my colleagues and I have done that,” Cai said. “Using CELF, we have shown it is possible to create cost-effective fuels from biomass and lignin and help curb our contribution of carbon emissions into the atmosphere.”
Directing CO2 electroreduction pathways for selective C2 product formation using single-site doped copper catalysts
by Zhengyuan Li, Peng Wang, Xiang Lyu, Vamsi Krishna Reddy Kondapalli, Shuting Xiang, Juan D. Jimenez, Lu Ma, Takeshi Ito, Tianyu Zhang, Jithu Raj, Yanbo Fang, Yaocai Bai, Jianlin Li, Alexey Serov, Vesselin Shanov, Anatoly I. Frenkel, Sanjaya D. Senanayake, Shize Yang, Thomas P. Senftle, Jingjie Wu in Nature Chemical Engineering
Engineers at the University of Cincinnati created a more efficient way of converting carbon dioxide into valuable products while simultaneously addressing climate change.
In his chemical engineering lab in UC’s College of Engineering and Applied Science, Associate Professor Jingjie Wu and his team found that a modified copper catalyst improves the electrochemical conversion of carbon dioxide into ethylene, the key ingredient in plastic and a myriad of other uses.
Ethylene has been called “the world’s most important chemical.” It is certainly among the most commonly produced chemicals, used in everything from textiles to antifreeze to vinyl. The chemical industry generated 225 million metric tons of ethylene in 2022. Wu said the process holds promise for one day producing ethylene through green energy instead of fossil fuels. It has the added benefit of removing carbon from the atmosphere. Wu’s students, including lead author and UC graduate Zhengyuan Li, collaborated with Rice University, Oak Ridge National Laboratory, Brookhaven National Laboratory, Stony Brook University and Arizona State University.
“Ethylene is a pivotal platform chemical globally, but the conventional steam-cracking process for its production emits substantial carbon dioxide,” Wu said. “By utilizing carbon dioxide as a feedstock rather than depending on fossil fuels, we can effectively recycle carbon dioxide.”
The electrocatalytic conversion of carbon dioxide produces two primary carbon products, ethylene and ethanol. Researchers found that using a modified copper catalyst produced more ethylene.
“Our research offers essential insights into the divergence between ethylene and ethanol during electrochemical CO2 reduction and proposes a viable approach to directing selectivity toward ethylene,” lead author Li said.
“This leads to an impressive 50% increase in ethylene selectivity,” Wu said. “Ideally, the goal is to produce a single product rather than multiple ones.”
Li said the next step is refining the process to make it more commercially viable. The conversion system loses efficiency as byproducts of the reaction such as potassium hydroxide begin forming on the copper catalyst.
“The electrode stability must be improved for commercial deployment. Our next focus is to enhance stability and extend its operation from 1,000 to 100,000 hours,” Li said.
Wu said these new technologies will help make the chemical industry greener and more energy efficient.
“The overarching objective is to decarbonize chemical production by utilizing renewable electricity and sustainable feedstock,” Wu said. “Electrifying the conversion of carbon dioxide to ethylene marks a significant stride in decarbonizing the chemical sector.”
Engineered Anchor Peptide LCI with a Cobalt Cofactor Enhances Oxidation Efficiency of Polystyrene Microparticles
by Dong Wang, Aaron A. Ingram, Julian Luka, Maochao Mao, Leon Ahrens, Marian Bienstein, Thomas P. Spaniol, Ulrich Schwaneberg, Jun Okuda in Angewandte Chemie International Edition
Polystyrene is a widespread plastic that is essentially not recyclable when mixed with other materials and is not biodegradable. A German research team has introduced a biohybrid catalyst that oxidizes polystyrene microparticles to facilitate their subsequent degradation. The catalyst consists of a specially constructed “anchor peptide” that adheres to polystyrene surfaces and a cobalt complex that oxidizes polystyrene.
Polystyrene — alone or in combination with other polymers — has many applications, from yogurt containers to instrument housings. In its foam form, mainly known under the trademarked name Styrofoam, it is, for example, used for insulation and packaging. A big disadvantage of polystyrene is its poor biodegradability, which leads to environmental pollution. When clean and not mixed with other materials, polystyrene is recyclable, but not when it is contaminated, or combined with other materials. In municipal recycling programs, mixed polystyrene plastic waste and degradation products, such as polystyrene nano- and microparticles, are difficult to process.
The problem lies in the fact that polystyrene is water-repellent and nonpolar and thus cannot react with common polar reactants. For a simple, economical, and energy efficient process to break down mixed polystyrene waste, the polystyrene must first be equipped with polar functional groups. A team led by Ulrich Schwaneberg and Jun Okuda at the RWTH in Aachen (Germany) has now developed a novel biohybrid catalyst to carry out this step.
The catalyst is based on compounds known as anchor peptides coupled with a cobalt complex. Anchor peptides are short peptide chains than can attach to surfaces. The team developed a special anchor peptide (LCI, Liquid Chromatography Peak I) that binds to the surface of polystyrene. One gram of this peptide is enough to coat a surface of up to 654 m2 with a monolayer within minutes by either spraying or dipping. A catalytically active cobalt complex is attached to the anchor peptide via a short linking piece.
The cobalt atom is “surrounded” by a macrocyclic ligand, a ring made of eight carbon and four nitrogen atoms (TACD, 1,4,7,10-tetraazacyclododecane). The catalyst accelerates oxidation of the C-H bonds in polystyrene to form polar OH groups (hydroxylation) by reaction with Oxone (potassium peroxymonosulfate), a common oxidizing agent. The binding of the anchor peptides is material-specific so in this case they immobilize the catalytically active cobalt near the polystyrene surface, which accelerates the reaction. This simple, inexpensive, and energy-efficient process is scalable through dipping and spray applications and is suitable for use on an industrial scale.
Through the use of conjugated chemical catalysts, this hybrid catalyst concept employing material-specific binding by anchor peptides could allow for the material-specific breakdown of further hydrophobic polymers such as polypropylene and polyethylene that cannot be economically broken down by enzymes.
Electrolytic Hydrogen Release from Hydrogen Boride Sheets
by Satoshi Kawamura, Akira Yamaguchi, Keisuke Miyazaki, Shin‐ichi Ito, Norinobu Watanabe, Ikutaro Hamada, Takahiro Kondo, Masahiro Miyauchi in Small
The looming threat of climate change has motivated scientists worldwide to look for cleaner alternatives to fossil fuels, and many believe hydrogen is our best bet. As an environmentally friendly energy resource, hydrogen (H2) can be used in vehicles and electric power plants without releasing carbon dioxide into the atmosphere.
However, storing and transporting H2 safely and efficiently remains a challenge. Compressed gaseous hydrogen poses a significant risk of explosion and leakage, whereas liquid hydrogen must be maintained at extremely low temperatures, which is costly. But what if we could store hydrogen directly in the molecular composition of other liquid or solid materials? This was the focus of a team of scientists from Japan, who, in a recent study p, investigated the potential of hydrogen boride (HB) sheets as practical hydrogen carriers.
Storing hydrogen in HB sheets is not an entirely new concept, and many aspects of their potential applications as hydrogen carriers have already been studied. However, getting the hydrogen out of the sheets is the tricky part. Heating at high temperatures or strong ultraviolet (UV) illumination is required to release hydrogen (H2) from HB sheets. However, both approaches have inherent disadvantages, such as high energy consumption or incomplete H2 release. Thus, the team delved into a potential alternative: electrochemical release.
Based on the mechanism of UV-induced H2 release from HB sheets, the team speculated that electron injection from a cathode electrode into HB nanosheets by an electric power supply could be a superior way to release H2 compared to UV irradiation or heating. Based on this theory, the researchers dispersed HB sheets into acetonitrile — an organic solvent — and applied a controlled voltage to the dispersion. These experiments revealed that nearly all of the electrons injected into the electrochemical system were used to convert H+ ions from the HB sheets into H2 molecules. Notably, the Faradaic efficiency of this process, which measures how much electrical energy is converted into chemical energy, was over 90%.
The team also conducted isotope tracing experiments to confirm that the electrochemically released H2 originated from the HB sheets and not through some other chemical reaction. Moreover, they also employed scanning electron microscopy and X-ray photoelectron spectroscopy to characterize the sheets before and after H2 release, yielding further insights into the underlying mechanisms of the process. These findings contribute to the development of safe and lightweight hydrogen carriers with low energy consumption.
Although the team studied the dispersed form of the HB sheets in the published paper, the current findings are applicable to film or bulk-based HB sheet systems for H2 release. Moreover, the team will investigate the rechargeability of HB sheets after dehydrogenation in a future study.
Modeling of yarn-shaped supercapacitors — Unraveling its length dependent output
by Nanfei He, Xi Zhang, Junhua Song, Feng Zhao, Wei Gao in Journal of Power Sources
As interest in wearable technology has surged, research into creating energy-storage devices that can be woven into textiles has also increased. Researchers at North Carolina State University have now identified a “sweet spot” at which the length of a threadlike energy storage technology called a “yarn-shaped supercapacitor” (YSC) yields the highest and most efficient flow of energy per unit length.
“When it comes to the length of the YSC, it’s a tradeoff between power and energy,” said Wei Gao, corresponding author of a paper on the work and an associate professor of textile engineering, chemistry and science at NC State. “It’s not only about how much energy you can store, but also the internal resistance we care about.”
Specifically, the researchers found that YSCs in the 40–60 centimeter range provided the best overall energy output. Previous research on YSCs has delivered varied and sometimes conflicting results when it comes to length-dependent energy output.
The aim of the new study, Gao said, was to provide a consistent, comprehensive model to explain changes in YSC performance across a wide range of lengths. To do this, researchers first fabricated several YSCs using pairs of activated carbon-incorporated electrode yarns and a gel electrolyte. Nylon threads were wrapped around each yarn to prevent shorting, and then the two electrodes were plied together and coated further with the same gel electrolyte.
Researchers created these YSCs in segments ranging from 10 to 300 cm long, and then ran electrical currents of varying frequencies through them. This allowed them to measure two characteristics; internal resistance, which measures how much electrical current is impeded while trying to move through a battery, and capacitance, which is the ability to store electrical energy.
The researchers found that capacitance generally increased linearly with length between 10 and 60 cm, after which gains in capacitance slowed significantly as length increased. The results were also influenced by the frequency of the electricity — or the rate at which the electrical current oscillates.
Depending on the electrical frequency of the current, the YSCs would see diminishing gains in capacitance up to the 300 cm in length, though some plateaued at around 150 cm. Mathematical models also showed that YSCs between 40–80 cm exhibited the lowest internal resistance, which led researchers to determine that 40–60 cm was the most efficient length overall. Lead author Nanfei He, a postdoctoral research scholar at NC State, said the study is part of a larger effort aimed at creating YSCs that can be integrated into clothing.
“Identifying the optimal length of YSCs is critical for their effective utilization, guiding the development of strategies for seamless integration into fabrics,” He said.
“Imagine you can make a yarn, just a regular textile yarn, that you also make into a battery,” Gao said. “You can basically hide it in your clothing. If you can do that, you can add so many more functions to your clothing.”
More work needs to be done before YSCs become viable for practical applications.
“The technology is not mature yet, and that’s why there is so much funding and so much interest in developing it,” Gao said.
“We can make yarn batteries, but can we make them durable, reliable, and safe? Can we make them washable? If you’re going to put it on your body, there are so many other challenges besides its energy-storage functions. Right now we’re focused on the reliability aspect, making sure that if you twist and move the yarn around it will still work. That plus safety are the main issues, and I think once we achieve those two it will broaden the scope of their applications by a lot.”
High-resolution structure and biochemical properties of the LH1–RC photocomplex from the model purple sulfur bacterium, Allochromatium vinosum
by Kazutoshi Tani, Ryo Kanno, Ayaka Harada, Yuki Kobayashi, Akane Minamino, Shinji Takenaka, Natsuki Nakamura, Xuan-Cheng Ji, Endang R. Purba, Malgorzata Hall, Long-Jiang Yu, Michael T. Madigan, Akira Mizoguchi, Kenji Iwasaki, Bruno M. Humbel, Yukihiro Kimura, Zheng-Yu Wang-Otomo in Communications Biology
Photosynthetic bacteria, unlike plants, do not generate oxygen as a photosynthetic byproduct because they use hydrogen sulfide instead of water to convert solar energy into chemical energy (electrons). This process is orchestrated by a protein complex, the light-harvesting 1-reaction center (LH1-RC). Numerous PSB thrive in calcium-rich environments, such as hot springs and seawater. In the three-dimensional LH1-RC structure, the LH1 antenna protein is typically associated with calcium. However, the photosynthetic mechanism remains elusive in Allochromatium vinosum, a model species of autotrophic bacteria capable of thriving in low-calcium or soft-water environments, as hypothetically, calcium is not involved in the photosynthetic process in this model.
Using cryo-electron microscopy, the researchers revealed the LH1-RC structures of this model species at a resolution that enabled individual amino acid visualization. These observations revealed calcium binding only at six specific sites in the LH1 subunit.
In contrast, the closely related thermophilic bacterium Thermochromatium tepidum displayed calcium attachment across all 16 LH1 subunits, indicating a calcium binding dependence on the amino acid sequence pattern.
These results imply an evolutionary adaptation in this species, enabling it to bind trace amounts of calcium in low-calcium environments, thereby improving its thermal stability for photosynthesis. These findings would potentially advance the efficient use of solar energy, and contribute to environmental protection, and highlight the capability of certain species to conduct photosynthesis in freshwater while detoxifying hydrogen sulfide, which is toxic to numerous organisms, into sulfur.
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