Tag Archives: #hydrogen

Making Clean Hydrogen Is Hard, But Researchers Just Solved a Major Hurdle (Chemistry)

For decades, researchers around the world have searched for ways to use solar power to generate the key reaction for producing hydrogen as a clean energy source — splitting water molecules to form hydrogen and oxygen. However, such efforts have mostly failed because doing it well was too costly, and trying to do it at a low cost led to poor performance.

Now, researchers from The University of Texas at Austin have found a low-cost way to solve one half of the equation, using sunlight to efficiently split off oxygen molecules from water. The finding, published recently in Nature Communications, represents a step forward toward greater adoption of hydrogen as a key part of our energy infrastructure.

As early as the 1970s, researchers were investigating the possibility of using solar energy to generate hydrogen. But the inability to find materials with the combination of properties needed for a device that can perform the key chemical reactions efficiently has kept it from becoming a mainstream method.

“You need materials that are good at absorbing sunlight and, at the same time, don’t degrade while the water-splitting reactions take place,” said Edward Yu, a professor in the Cockrell School’s Department of Electrical and Computer Engineering. “It turns out materials that are good at absorbing sunlight tend to be unstable under the conditions required for the water-splitting reaction, while the materials that are stable tend to be poor absorbers of sunlight. These conflicting requirements drive you toward a seemingly inevitable tradeoff, but by combining multiple materials — one that efficiently absorbs sunlight, such as silicon, and another that provides good stability, such as silicon dioxide — into a single device, this conflict can be resolved.”

However, this creates another challenge — the electrons and holes created by absorption of sunlight in silicon must be able to move easily across the silicon dioxide layer. This usually requires the silicon dioxide layer to be no more than a few nanometers, which reduces its effectiveness in protecting the silicon absorber from degradation.

The key to this breakthrough came through a method of creating electrically conductive paths through a thick silicon dioxide layer that can be performed at low cost and scaled to high manufacturing volumes. To get there, Yu and his team used a technique first deployed in the manufacturing of semiconductor electronic chips. By coating the silicon dioxide layer with a thin film of aluminum and then heating the entire structure, arrays of nanoscale “spikes” of aluminum that completely bridge the silicon dioxide layer are formed. These can then easily be replaced by nickel or other materials that help catalyze the water-splitting reactions.

When illuminated by sunlight, the devices can efficiently oxidize water to form oxygen molecules while also generating hydrogen at a separate electrode and exhibit outstanding stability under extended operation. Because the techniques employed to create these devices are commonly used in manufacturing of semiconductor electronics, they should be easy to scale for mass production.

The team has filed a provisional patent application to commercialize the technology.

Improving the way hydrogen is generated is key to its emergence as a viable fuel source. Most hydrogen production today occurs through heating steam and methane, but that relies heavily on fossil fuels and produces carbon emissions.

There is a push toward “green hydrogen” which uses more environmentally friendly methods to generate hydrogen. And simplifying the water-splitting reaction is a key part of that effort.

Water splitting graphic
Graphic shows the basic geometry and functionality of the photoanode device. © Cockrell School of Engineering, The University of Texas at Austin

Hydrogen has potential to become an important renewable resource with some unique qualities. It already has a major role in significant industrial processes, and it is starting to show up in the automotive industry. Fuel cell batteries look promising in long-haul trucking, and hydrogen technology could be a boon to energy storage, with the ability to store excess wind and solar energy produced when conditions are ripe for them.

Going forward, the team will work to improve the efficiency of the oxygen portion of water-splitting by increasing the reaction rate. The researchers’ next major challenge is then to move on to the other half of the equation.

“We were able to address the oxygen side of the reaction first, which is the more challenging part, ” Yu said, “but you need to perform both the hydrogen and oxygen evolution reactions to completely split the water molecules, so that’s why our next step is to look at applying these ideas to make devices for the hydrogen portion of the reaction.”

This research was funded by the U.S. National Science Foundation through the Directorate for Engineering and the Materials Research Science and Engineering Centers (MRSEC) program. Yu worked on the project with UT Austin students Soonil Lee and Alex De Palma, along with Li Ji, a professor at Fudan University in China.

Featured image: The team’s experimental water-splitting apparatus. © Cockrell School of Engineering, The University of Texas at Austin

Reference: Lee, S., Ji, L., De Palma, A.C. et al. Scalable, highly stable Si-based metal-insulator-semiconductor photoanodes for water oxidation fabricated using thin-film reactions and electrodeposition. Nat Commun 12, 3982 (2021). https://doi.org/10.1038/s41467-021-24229-y

Provided by Cockrell School of Engineering

GMRT Measures The Atomic Hydrogen Gas Mass In Galaxies 9 Billion Years Ago (Cosmology)

A team of astronomers from the National Centre for Radio Astrophysics (NCRA-TIFR) in Pune, and the Raman Research Institute (RRI), in Bangalore, has used the Giant Metrewave Radio Telescope (GMRT) to measure the atomic hydrogen gas content of galaxies 9 billion years ago, in the young universe. This is the earliest epoch in the universe for which there is a measurement of the atomic hydrogen content of galaxies. The new result is a crucial confirmation of the group’s earlier result, where they had measured the atomic hydrogen content of galaxies 8 billion years ago, and pushes our understanding of galaxies to even earlier in the universe. The new research has been published in the 2 June 2021 issue of The Astrophysical Journal Letters.

Galaxies consist of mostly gas and stars, with new stars forming from the existing gas during the life of a galaxy. Stars formed much more frequently when the universe was young than they do today. Astronomers have known for more than two decades that the star formation activity in galaxies was at its highest about 8-10 billion years ago, and has declined steadily thereafter. Until recently, the cause of this decline was unknown, mostly because we have had no information about the amount of atomic hydrogen gas, the main fuel for star formation, in galaxies at these early times. This changed last year when a team of astronomers from NCRA and RRI, including some of the authors from the present study, used the upgraded GMRT to obtain the first measurement of the atomic hydrogen gas content of galaxies about 8 billion years ago, when the star-formation activity of the Universe began to decline. They found that the likely cause for the decline in star formation in galaxies is that galaxies were running out of fuel.

Aditya Chowdhury, a Ph.D. student at NCRA-TIFR, and the lead author of both the new study and the 2020 one, said, “Our new results are for galaxies at even earlier times, but still towards the end of the epoch of maximum star-formation activity. We find that galaxies 9 billion years ago were rich in atomic gas, with nearly three times as much mass in atomic gas as in stars! This is very different from galaxies today like the Milky Way, where the gas mass is nearly ten times smaller than the mass in stars.”

The measurement of the atomic hydrogen gas mass was done by using the GMRT to search for a spectral line in atomic hydrogen, which can only be detected with radio telescopes. Unfortunately, this “21 cm” signal is very weak, and hence nearly impossible to detect from individual galaxies at such large distances, around 30 billion light years from us, even with powerful telescopes like the GMRT. The team hence used a technique called “stacking” to improve the sensitivity. This allowed them to measure the average gas content of nearly 3,000 galaxies, by combining their 21 cm signals.

“The observations of our study were carried out around 5 years ago, before the GMRT was upgraded in 2018. We used the original receivers and electronics chain of the GMRT before its upgrade, which had a narrow bandwidth. We could hence cover only a limited number of galaxies; this is why our current study covers 3000 galaxies, compared to the 8,000 galaxies of our 2020 study with the wider bandwidth of the upgraded GMRT.”, said Nissim Kanekar of NCRA-TIFR, a co-author of the study.

Barnali Das, another Ph.D. student of NCRA-TIFR, added, “Although we had fewer galaxies, we increased our sensitivity by observing for longer, with nearly 400 hours of observations. The large volume of data meant that the analysis took a long time!”.

“The star formation in these early galaxies is so intense that they would consume their atomic gas in just two billion years. And, if the galaxies could not acquire more gas, their star formation activity would decline, and finally cease.”, said Chowdhury. “It thus appears likely that the cause of the declining star-formation in the Universe is simply that galaxies were not able to replenish their gas reservoirs after some epoch, probably because there wasn’t enough gas available in their environments.”

“Reproducibility is foundational to science! Last year, we reported the first measurement of the atomic gas content in such distant galaxies. With the present result, using a completely different set of receivers and electronics, we now have two independent measurements of the atomic gas mass in these early galaxies. This would have been hard to believe, even a few years ago!”, said Kanekar.

K. S. Dwarakanath of RRI, a co-author of the study, mentioned “Detecting the 21 cm signal from distant galaxies was the main original goal of the GMRT, and continues to be a key science driver for building even more powerful telescopes like the Square Kilometre Array. These results are extremely important for our understanding of galaxy evolution.”.

The research was carried out by Aditya Chowdhury, Nissim Kanekar, and Barnali Das of NCRA-TIFR, and Shiv Sethi and K. S. Dwarakanath of RRI. The Giant Metrewave Radio Telescope was built and is operated by NCRA-TIFR. The research was funded by the Department of Atomic Energy, India, and the Department of Science and Technology, India.

Featured image: The spectrum of the detected GMRT 21cm signal (left panel) and an image (right panel). © Aditya Chowdhury

Reference: Aditya Chowdhury, Nissim Kanekar, Barnali Das, K. S. Dwarakanath, and Shiv Sethi, “Giant Metrewave Radio Telescope Detection of Hi 21 cm Emission from Star-forming Galaxies at z ≈ 1.3”, The Astrophysical Journal Letters, 913(2), 2021. Link to paper

Provided by TIFR

Etching Process Enhances The Extraction of Hydrogen During Water Electrolysis (Chemistry)

Extracting hydrogen from water through electrolysis offers a promising route for increasing the production of hydrogen, a clean and environmentally friendly fuel. But one major challenge of water electrolysis is the sluggish reaction of oxygen at the anode, known as the oxygen evolution reaction (OER).

A collaboration between researchers at Hunan University and Shenzhen University in China, has led to a discovery that promises to improve the OER process. In their recent paper, published in the KeAi journal Green Energy & Environment, they report that etching – or, in other words, chemically removing – the oxide overlayers that form on the surface of the metal phosphide electrocatalysts regularly used in electrolysis, can increase OER efficiency.

Professor Shuangyin Wang of the State Key Laboratory of Chem/Bio-sensing and Chemometrics at Hunan University led the study. He explains: “While metal phosphides are often used as catalysts due to their unique physicochemical properties such as high conductivity, earth-abundance reserves and excellent performance, a common, but often neglected fact is that they are quick to suffer atmospheric oxidation when they are exposed to air. This causes them to form oxide overlayers on their surface, which can change the surface reconstruction process and confuse the structure-performance relationship.”

To solve this problem, Professor Wang and his colleagues decided to etch away those oxide overlayers using a dielectric barrier discharge plasma technique. And they discovered that the etching process not only accelerated the surface reconstruction process, but greatly enhanced the formation of metal hydroxides and OER activity.

According to Prof. Wang: “These findings are helpful for understanding the structure-performance relationship of metal phosphides in electrooxidation reaction. And we suspect that the same etching process has the potential to be used on other oxygen-susceptible metal compounds such as chalcogenides, nitrides and carbides.

“Our hope is that our study guides the rational design and engineering of more efficient electrocatalysts for water electrolysis.”

Featured image: Schematic diagram of the etching process used on metal phosphide electrocatalysts © authors

Reference: Tehua Wang, Xian-Zhu Fu, Shuangyin Wang, Etching oxide overlayers of NiFe phosphide to facilitate surface reconstruction for oxygen evolution reaction, Green Energy & Environment, 2021, , ISSN 2468-0257, https://doi.org/10.1016/j.gee.2021.03.005. (https://www.sciencedirect.com/science/article/pii/S2468025721000388)

Provided by KEAI Communications

Argonne Scientists Weigh Benefits of Increased Hydrogen Production (Science and Technology)

Hydrogen technology has the potential to transform aspects of the energy landscape, according to a new report from Argonne scientists.

The hydrogen economy is an aspiration for scientists and policymakers who seek to fully integrate sustainable, clean hydrogen in our larger energy system.

Many believe that hydrogen could play a key role as a zero-carbon and environmentally sustainable energy carrier that could dramatically reshape the contours of our entire economy, from transportation to manufacturing.

In a new study, researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and National Renewable Energy Laboratory have taken a deeper look at the potential for growth in hydrogen demand in the United States given current and emerging technologies. They evaluated six demand sectors, including synthetic fuels, biofuels, hydrogen injection in natural gas pipelines, metals manufacturing, and transportation.

The study is one example of the work that DOE’s Hydrogen and Fuel Cell Technologies Office within the Energy Efficiency and Renewable Energy Office (EERE) is funding to advance DOE’s H2@Scale vision for clean and affordable hydrogen production, storage, transport and use across the economy.

“The United States produces about 10 million metric tons of hydrogen per year, primarily for the petrochemical sector,” said Argonne senior scientist Amgad Elgowainy. ​“There is strong interest emerging in renewable production of hydrogen, primarily to decarbonize industrial and transportation demands. Our report evaluates the potential size of these demand sectors, and their sensitivity to the price of hydrogen.”

In the report, Elgowainy and his colleagues evaluated hydrogen as part of synthetic fuels, an area where Argonne also has significant other ongoing life cycle and technoeconomic analysis. Synthetic fuels are advantageous because they can leverage existing infrastructure for liquid fuel, and also recycle waste carbon dioxide streams to create new forms of usable energy. Pairing carbon dioxide with hydrogen inputs could create a broad array of new forms of hydrocarbon fuels that could find their way into a variety of different uses across transportation and industry, Elgowainy said.

The Argonne study on hydrogen demand potential complements another recently released H2@Scale analysis that was led by the National Renewable Energy Laboratory and estimated the economic potential of hydrogen consumption, given hydrogen supply in various future energy system scenarios. This study identified the economic potential of hydrogen consumption in the US as two to four times current demand, depending on R&D advancements, infrastructure availability, and the prices of electricity and natural gas. Ongoing work at Argonne is attempting to assess the life cycle emissions of these sectors, as well as the cost drivers and potential for hydrogen demand in other emerging applications.

Featured image: A graphical depiction of the hydrogen economy, showing the many uses for hydrogen in industry and transportation. (Image by U.S. Department of Energy.)

Reference: A. Elgowainy, M. Mintz, U. Lee, T. Stephens, P. Sun, K. Reddi, Y. Zhou, G. Zang, M. Ruth, P. Jadun, E. Connelly, R. Boardman, “Assessment of Potential Future Demands for Hydrogen in the United States”, Energy Systems, 2020. https://greet.es.anl.gov/publication-us_future_h2

Provided by Argonne National Laboratory

First Direct Band Gap Measurements of Wide-gap Hydrogen Using Inelastic X-ray Scattering (Physics)

Utilizing a newly developed state-of-the-art synchrotron technique, a group of scientists led by Dr. Ho-kwang Mao, Director of HPSTAR, conducted the first-ever high-pressure study of the electronic band and gap information of solid hydrogen up to 90 GPa. Their innovative high pressure inelastic X-ray scattering result serves as a test for direct measurement of the process of hydrogen metallization and opens a possibility to resolve the electronic dispersions of dense hydrogen. This work is published in the recent issue of Physical Review Letters.

The pressure-induced evolution of hydrogen’s electronic band from a wide gap insulator to a closed gap metal, or metallic hydrogen, has been a longstanding problem in modern physics. However, hydrogen’s remarkably high energy has prevented the electronic band gap from being directly observed under pressure before. Existing probes, such as electrical conductivity, optical absorption, or reflection spectroscopy measurements, are limited and provide little information on a wide-gap insulator. “All previous studies of the band gap in insulating hydrogen under compression were based on an indirect scheme using optical measurements,” explains Dr. Mao.

The team used high-brilliance, high-energy synchrotron radiation to develop an inelastic x-ray (IXS) probe, yielding electronic band information of hydrogen in situ under high pressure in a diamond anvil cell (DAC). “The development of our DAC-IXS technique for this project took an international team of many experts in synchrotron inelastic X-ray spectroscopy, instrumentation, and ultra-high-pressure techniques over five years to complete,” said Dr. Bing Li, the first author.

“Actually, the real beginning of this project can be traced back more than 20 years, and these results are the culmination of all that preparation and experimentation. A true testament to the enormous efforts and talents of the team involved,” said Dr. Mao. The novel IXS probe technique enabled an inaccessible and extensive UV energy range of 45 eV to be measured, showing how dense hydrogen’s electronic joint density of states and band gap evolve with pressure. The electronic band gap decreased linearly from 10.9 eV to 6.57 eV, with an 8.6 times densification from zero pressure up to 90 GPa.

These developments in state-of-the-art synchrotron capabilities with submicron to nanometer-scaled X-ray probes will only extend future experimental possibilities. Advances of IXS to higher pressure could place the semiconducting region of phases II-V within reach and enable the study of hydrogen metallization through direct and quantitative electronic band gap measurements.

This work overcomes formidable technical challenges, achieving direct experimental measurements of hydrogen’s electronic band and its gap for the first time.

Featured image: IXS spectra of hydrogen under compression and the inset shows the band gap energy narrowing as a function of density. © Bing Li

Reference: Bing Li, Yang Ding, Duck Young Kim, Lin Wang, Tsu-Chien Weng, Wenge Yang, Zhenhai Yu, Cheng Ji, Junyue Wang, Jinfu Shu, Jiuhua Chen, Ke Yang, Yuming Xiao, Paul Chow, Guoyin Shen, Wendy L. Mao, and Ho-Kwang Mao, “Probing the Electronic Band Gap of Solid Hydrogen by Inelastic X-Ray Scattering up to 90 GPa”, Phys. Rev. Lett. 126, 036402 – Published 21 January 2021. https://doi.org/10.1103/PhysRevLett.126.036402

Provided by Center for High Pressure Science and Technology Advanced Research

Novel Donor-Acceptor System Developed for Highly-effective Sunlight-driven Hydrogen Evolution (Chemistry)

Sunlight-driven hydrogen production has been considered as one of the most important renewable energy sources, while active photocatalyst is a prerequisite for efficient hydrogen production. 2D covalent organic frameworks (COFs) could have well-defined arrangements of photo- and electro-active units that serve as electron or hole transport channels for solar energy harvesting and conversion, however, their insufficient charge transfer and rapid charge recombination impede the sunlight-driven photocatalytic performance.

Figure 1. Synthetic route for PyTz-COF (Image by SARI)  

Motivated by such a challenge, a research team led by Prof. WEN Ke and Prof. YANG Hui at the Shanghai Advanced Research Institute (SARI), collaborating with Prof. ZHANG Yuebiao at ShanghaiTech University, reported a novel photoactive 2D COF from donor pyrene (Py) and acceptor Tz building units, which enabled remarkable photogenerated charge separation and efficient charge migration. The research results were featured on front cover of Angewandte Chemie International Edition

Based on physical structural characterizations, the researchers conjectured that Thiazolo[5,4-d]Thiazole might help to boost photo-absorbing ability of previously reported TpTz COF. They constructed the new donor-acceptor system from the electron-rich Py and electron-deficient thiazolo[5,4-d]thiazole (Tz).

Figure 2. Photoelectrochemical and photocatalytic performance of PyTz-COF (Image by SARI)

According to the researchers, the PyTz-COF demonstrates high photocatalytic activitity for sustainable and efficient water splitting with a photocurrent up to 100 uA cm-2 at 0.2 V vs. RHE and could reach a hydrogen evolution rate of 2,072.4 umolg-1 h-1, which exceeds the values of many previously reported COFs. 

This study not only realizes the effective separation and migration of photogenerated electrons and holes, but also reveals a new mechanism of COF photocatalysis. More importantly, it would inspire future development of sunlight-driven photocatalysts for solar energy harvesting and conversion. 

Reference: Wenqian Li, Xiaofeng Huang, Tengwu Zeng, Yahu A. Liu, Weibo Hu, Prof. Hui Yang, Prof. Yue‐Biao Zhang, Prof. Ke Wen, “Thiazolo[5,4‐d]thiazole‐Based Donor–Acceptor Covalent Organic Framework for Sunlight‐Driven Hydrogen Evolution”, Angew. Chem. Int. Ed. 2021, 60, 1869. https://onlinelibrary.wiley.com/doi/10.1002/anie.202014408

Provided by Chinese Academy of Sciences

Chemists Describe a New Form of Ice (Chemistry)

Scientists from the United States, China, and Russia have described the structure and properties of a novel hydrogen clathrate hydrate that forms at room temperature and relatively low pressure. Hydrogen hydrates are a potential solution for hydrogen storage and transportation, the most environmentally friendly fuel. The research was published in the journal Physical Review Letters.

A novel hydrogen clathrate hydrate © Pavel Odinev / Skoltech

Ice is a highly complex substance with multiple polymorphic modifications that keep growing in number as scientists make discoveries. The physical properties of ice vary greatly, too: for example, hydrogen bonds become symmetric at high pressures, making it impossible to distinguish a single water molecule, whereas low pressures cause proton disorder, placing water molecules in many possible spatial orientations within the crystal structure. The ice around us, including snowflakes, is always proton-disordered. Ice can incorporate xenon, chlorine, carbon dioxide, or methane molecules and form gas hydrates, which often have a different structure from pure ice. The vast bulk of Earth’s natural gas exists in the form of gas hydrates.

In their new study, chemists from the United States, China, and Russia focused on hydrogen hydrates. Gas hydrates hold great interest both for theoretical research and practical applications, such as hydrogen storage. If stored in its natural form, hydrogen poses an explosion hazard, whereas density is way too low even in compressed hydrogen. That is why scientists are looking for cost-effective hydrogen storage solutions.

“This is not the first time we turn to hydrogen hydrates. In our previous research, we predicted a novel hydrogen hydrate with 2 hydrogen molecules per water molecule. Unfortunately, this exceptional hydrate can only exist at pressures above 380,000 atmospheres, which is easy to achieve in the lab but is hardly usable in practical applications. Our new paper describes hydrates that contain less hydrogen but can exist at much lower pressures,” Skoltech professor Artem R. Oganov says.

The crystal structure of hydrogen hydrates strongly depends on pressure. At low pressures, it has large cavities which, according to Oganov, resemble Chinese lanterns, each accommodating hydrogen molecules. As pressure increases, the structure becomes denser, with more hydrogen molecules packed into the crystal structure, although their degrees of freedom become significantly fewer.

In their research published in the Physical Review Letters, the scientists from the Carnegie Institution of Washington (USA) and the Institute of Solid State Physics in Hefei (China) led by Alexander F. Goncharov, a Professor at these two institutions, performed experiments to study the properties of various hydrogen hydrates and discovered an unusual hydrate with 3 water molecules per hydrogen molecule. The team led by Professor Oganov used the USPEX evolutionary algorithm developed by Oganov and his students to puzzle out the compound’s structure responsible for its peculiar behavior. The researchers simulated the experiment’s conditions and found a new structure very similar to the known proton-ordered C1 hydrate but differing from C1 in water molecule orientations. The team showed that proton disorder should occur at room temperature, thus explaining the X-ray diffraction and Raman spectrum data obtained in the experiment.

Reference: Yu Wang, Konstantin Glazyrin, Valery Roizen, Artem R. Oganov, Ivan Chernyshov, Xiao Zhang, Eran Greenberg, Vitali B. Prakapenka, Xue Yang, Shu-qing Jiang, and Alexander F. Goncharov, “Novel Hydrogen Clathrate Hydrate”, Phys. Rev. Lett. 125, 255702 – Published 18 December 2020. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.255702

Provided by SKOLTECH

Curtin Collision Models Impact The Future of Energy (Physics)

A new Curtin University-created database of electron-molecule reactions is a major step forward in making nuclear fusion power a reality, by allowing researchers to accurately model plasmas containing molecular hydrogen.

Lead researcher, Curtin University PhD candidate Liam Scarlett.

The Curtin study, published in the Atomic Data and Nuclear Data Tables journal, is supplying data to the International Thermonuclear Experimental Reactor (ITER) – one of the largest scientific projects in the world aimed at developing fusion technology for electricity production on Earth.

Lead researcher, PhD candidate and Forrest Scholar Liam Scarlett from the Theoretical Physics Group in Curtin’s School of Electrical Engineering, Computing and Mathematical Sciences said his calculations and the resulting collision database will play a crucial role in the development of fusion technology.

“Our electron-molecule collision modelling is an exciting step in the global push to develop fusion power – a new, clean electricity source. Fusion is the nuclear reaction which occurs when atoms collide and fuse together, releasing huge amounts of energy. This process is what powers the Sun, and recreating it on Earth requires detailed knowledge of the different types of collisions which take place in the fusion plasma – that’s where my research comes in,” Mr Scarlett said.

“We developed mathematical models and computer codes, and utilised the Perth-based Pawsey Supercomputing Centre to calculate the probabilities of different reactions taking place during collisions with molecules. The molecules we looked at here are those which are formed from atoms of hydrogen and its isotopes, as they play an important role in fusion reactors.

“Until now the available data was incomplete, however our molecular collision modelling has produced an accurate and comprehensive database of more than 60,000 electron-molecule reaction probabilities which, for the first time, has allowed a team in Germany to create an accurate model for molecular hydrogen in the ITER plasma.

“This is significant because their model will be used to predict how the plasma will radiate, leading to a better understanding of the plasma physics, and the development of diagnostic tools which are vital for controlling the fusion reaction.”

The research project was funded by the United States Air Force Office of Scientific Research as part of an international research endeavour to harness fusion power as a future energy source.

Research supervisor and co-author Professor Dmitry Fursa, from Curtin’s School of Electrical Engineering, Computing and Mathematical Sciences, said fusion power is attractive due to its virtually unlimited fuel supply (hydrogen) and the lack of long-lived radioactive waste or carbon emissions.

“Fusion is one of the biggest projects in the world right now. You can harness an enormous amount of energy from the reaction that occurs when you take hydrogen atoms and fuse them together,” Professor Fursa said.

“This new and comprehensive electron-molecule collision modelling has provided a solid basis for other researchers to continue their work into developing an efficient reactor to re-create the Sun’s fusion process here on Earth.”

The full research paper, Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues, published in Atomic Data and Nuclear Data Tables, is available online here.

The paper was written in collaboration with researchers at Los Alamos National Laboratory and the National Institute of Standards and Technology in the USA.

References: Liam H. Scarlett, Dmitry V. Fursa, Mark C. Zammit, Igor Bray, Yuri Ralchenko, Kayla D. Davie,
Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: I. Fully vibrationally-resolved electronic excitation of H2(X1危g+), Atomic Data and Nuclear Data Tables, Volume 137, 2021, 101361,
ISSN 0092-640X,

Provided by Curtin University

Research Creates Hydrogen-producing Living Droplets, Paving Way For Alternative Future Energy Source (Chemistry)

Scientists have built tiny droplet-based microbial factories that produce hydrogen, instead of oxygen, when exposed to daylight in air.

Electron microscopy image of a densely packed droplet of hydrogen-producing algal cells. Scale bar, 10 micrometers. ©Prof Xin Huang, Harbin Institute of Technology

The findings of the international research team based at the University of Bristol and Harbin Institute of Technology in China, are published today in Nature Communications.

Normally, algal cells fix carbon dioxide and produce oxygen by photosynthesis. The study used sugary droplets packed with living algal cells to generate hydrogen, rather than oxygen, by photosynthesis.

Hydrogen is potentially a climate-neutral fuel, offering many possible uses as a future energy source. A major drawback is that making hydrogen involves using a lot of energy, so green alternatives are being sought and this discovery could provide an important step forward.

The team, comprising Professor Stephen Mann and Dr Mei Li from Bristol’s School of Chemistry together with Professor Xin Huang and colleagues at Harbin Institute of Technology in China, trapped ten thousand or so algal cells in each droplet, which were then crammed together by osmotic compression. By burying the cells deep inside the droplets, oxygen levels fell to a level that switched on special enzymes called hydrogenases that hijacked the normal photosynthetic pathway to produce hydrogen. In this way, around a quarter of a million microbial factories, typically only one-tenth of a millimetre in size, could be prepared in one millilitre of water.

To increase the level of hydrogen evolution, the team coated the living micro-reactors with a thin shell of bacteria, which were able to scavenge for oxygen and therefore increase the number of algal cells geared up for hydrogenase activity.

Although still at an early stage, the work provides a step towards photobiological green energy development under natural aerobic conditions.

Professor Stephen Mann, Co-Director of the Max Planck Bristol Centre for Minimal Biology at Bristol, said: “Using simple droplets as vectors for controlling algal cell organization and photosynthesis in synthetic micro-spaces offers a potentially environmentally benign approach to hydrogen production that we hope to develop in future work.”

Professor Xin Huang at Harbin Institute of Technology added: “Our methodology is facile and should be capable of scale-up without impairing the viability of the living cells. It also seems flexible; for example, we recently captured large numbers of yeast cells in the droplets and used the microbial reactors for ethanol production.”

References: Xu, Z., Wang, S., Zhao, C. et al. Photosynthetic hydrogen production by droplet-based microbial micro-reactors under aerobic conditions. Nat Commun 11, 5985 (2020). https://www.nature.com/articles/s41467-020-19823-5 https://doi.org/10.1038/s41467-020-19823-5

Provided by University of Bristol