Osaka University researchers develop efficient “green” hydrogen production system that operates at room temperature in air.
Hydrogen gas is a promising alternative energy source to overcome our reliance on carbon-based fuels, and has the benefit of producing only water when it is reacted with oxygen. However, hydrogen is highly reactive and flammable, so it requires careful handling and storage. Typical hydrogen storage materials are limited by factors like water sensitivity, risk of explosion, difficulty of control of hydrogen-generation. Hydrogen gas can be produced efficiently from organosilanes, some of which are suitably air-stable, non-toxic, and cheap. Catalysts that can efficiently produce hydrogen from organosilanes are therefore desired with the ultimate goal of realizing safe, inexpensive hydrogen production in high yield. Ideally, the catalyst should also operate at room temperature under aerobic conditions without the need for additional energy input.
A research team led by Kiyotomi Kaneda and Takato Mitsudome at Osaka University have now developed a catalyst that realizes efficient environmentally friendly hydrogen production from organosilanes. The catalyst is composed of gold nanoparticles with a diameter of around 2 nm supported on hydroxyapatite. The catalyst was synthesized from chloroauric acid using glutathione as a capping agent to prevent nanoparticle aggregation, resulting the formation of small size of gold nanoparticles. Glutathione-capped gold nanoparticles were then adsorbed on hydroxyapatite and glutathione was removed by subsequent calcination.
The team then added the nanoparticle catalyst to solutions of different organosilanes to measure its ability to induce hydrogen production. The nanoparticle catalyst displayed the highest turnover frequency and number attained to date for hydrogen production catalysts from organosilanes. For example, the nanoparticle catalyst converted 99% of dimethylphenylsilane to the corresponding silanol in just 9 min at room temperature, releasing an equimolar amount of hydrogen gas at the same time. Importantly, the catalyst was recyclable without loss of activity. On/off switching of hydrogen production was achieved using the nanoparticle catalyst because it could be easily separated from its organosilane substrate by filtration. The activity of the catalyst increased as the nanoparticle size decreased.
A prototype portable hydrogen fuel cell containing the nanoparticle catalyst and an organosilane substrate was fabricated. The fuel cell generated power in air at room temperature and could be switched on and off as desired. Images of the catalyst after use in the fuel cell resembled those of the unused catalyst, indicating that the hydroxyapatite-supported nanoparticle catalyst readily resisted aggregation.
Generation of hydrogen from inexpensive organosilane substrates under ambient conditions without additional energy input represents an exciting advance towards the goal of using hydrogen as a green energy source.
Addressing safety risks and energy loss for a society with hydrogen energy
A research group led by Professor Hiroyuki Nishide and Professor Kenichi Oyaizu from the Department of Applied Chemistry developed a hydrogen-carrying polymer, which can be molded as a tangible, safe, and compact plastic sheet.
Although technology developments and research on realizing hydrogen as a major energy source have gone under way, the conventional methods of storing and carrying hydrogen were accompanied by safety risks such as explosions. Hence, hydrogen-exposed organic compounds have been recently studied as hydrogen storage materials, for their ability to stably and reversibly store hydrogen by forming chemical bonds. However, these compounds require vessels or sealed tanks operated at high pressure and/or temperature and often encounter difficulty in their separation from the evolved hydrogen gas. A much safer and more efficient system for storing and storing and carrying hydrogen has been in demand.
The research group discovered that ketone (fluorenone) polymer, which can be molded as a plastic sheet, can fix hydrogen via a simple electrolytic hydrogenation at -1.5V (versus Ag/AgCl) in water at room temperature. On the other hand, fluorenol polymer, a hydrogenated alcohol derivative of fluorenone, can release hydrogen when heated at 80 degree Celsius with an aqueous iridium catalyst. What’s more, the group proved that the cycle of repeatedly fixing and releasing hydrogen under mild conditions without significant deterioration, leading to the developement of a portable, plastic ketone polymer with hydrogen that can be carried around in your pocket.
The advantages of the ketone/alcohol polymer include easy handling, moldability, robustness, non-flammability and low toxicity, and the research results are expected to make contributions in building distributed energy systems in regional areas.
Simpler process and higher efficiency creates great expectations for consumer market
Waseda University researchers have developed a new method for producing hydrogen, which is fast, irreversible, and takes place at much lower temperature using less energy. This innovation is expected to contribute to the spread of fuel cell systems for automobiles and homes.
Hydrogen has normally been extracted from methane and steam using a nickel catalyst at temperatures of over 700°C. However, the high temperature creates major challenges for widespread use.
The group led by Professor Yasushi Sekine, Waseda University Faculty of Science and Engineering, developed a method which allows hydrogen extraction at temperatures as low as 150~200°C. This shift greatly reduces energy input needed to produce hydrogen fuel, extends catalyst life, reduces the cost of construction materials, and reduces complexity of heat-management (cooling) systems.
Although the research group had already seen that a fast reaction would be possible even in the range of 150~200°C by applying a weak electric fields (surface protonics), the mechanism had not been fully understood.
In this research, the group is the first to explain the mechanism by observing the catalyst during reaction. Protons move quickly through water adsorbed on the catalyst’s surface, and protons’ surface “hopping” allows reaction to proceed at low temperatures. Furthermore, the collision of the protons and the adsorbents prevents reversal of the reaction.
As momentum grows for the commercialization of hydrogen, this research is not only applicable to hydrogen production, but also to many consumer products since the same mechanism makes it possible to lower the temperature for various reactions involving hydrogen or water. The process is already being applied to research for improving energy efficiency in automobiles by creating reactions between exhaust gases and fuel at low temperature.
Hydrogen is often described as the fuel of the future, particularly when applied to hydrogen-powered fuel cell vehicles. One of the main obstacles facing this technology – a potential solution to future sustainable transport – has been the lack of a lightweight, safe on-board hydrogen storage material.
A major new discovery by scientists at the universities of Oxford, Cambridge and Cardiff in the UK, and the King Abdulaziz City for Science and Technology (KACST) in Saudi Arabia, has shown that hydrocarbon wax rapidly releases large amounts of hydrogen when activated with catalysts and microwaves.
This discovery of a potential safe storage method, reported in the Nature journal Scientific Reports, could pave the way for widespread adoption of hydrogen-fuelled cars.
Study co-author Professor Peter Edwards, who leads the KACST-Oxford Petrochemical Research Centre (KOPRC), a KACST Centre of Excellence in Petrochemicals at Oxford University, said: ‘This discovery of a safe, efficient hydrogen storage and production material can open the door to the large-scale application of fuel cells in vehicles.’
Co-author Dr Tiancun Xiao, a senior research fellow at Oxford University, said: ‘Our discovery – that hydrogen can be easily and instantly extracted from wax, a benign material that can be manufactured from sustainable processes – is a major step forward. Wax will not catch fire or contaminate the environment. It is also safe for drivers and passengers.’
Co-author Professor Hamid Al-Megren, from the Materials Research Institute at KACST, said: ‘This is an exciting development – it will allow society to utilise fossil fuels or renewable-derived wax to generate on-board hydrogen for fuel cell applications without releasing any carbon dioxide into the air.’
Hydrocarbons are natural, hydrogen-rich resources with well-established infrastructures. The research team has developed highly selective catalysts with the assistance of microwave irradiation, which can extract hydrogen from hydrocarbons instantly through a non-oxidative dehydrogenation process. This will help unlock the longstanding bottleneck hindering the widespread adoption of hydrogen fuel technology.
Co-author Professor Angus Kirkland, from the Department of Materials at Oxford University and Science Director at the new electron Physical Science Imaging Centre (ePSIC) at Harwell Science and Innovation Campus, described the breakthrough as an exemplar of how Oxford is able to respond to key academic and industrial problems by using interdisciplinary resources and expertise.
Co-author Professor Sir John Meurig Thomas, from the Department of Materials Science and Metallurgy at the University of Cambridge, said the work could be extended so that many of the liquid components of refined petroleum and inexpensive solid catalysts can pave the way for the generation of massive quantities of high-purity hydrogen for other commercial uses, including CO2-free energy production.
Professor Edwards added: ‘Instead of burning fossil fuels, leading to CO2, we use them to generate hydrogen, which with fuel cells produces electric power and pure water. This is the future – transportation without CO2 and hot air.’
TAU researchers discover algae can yield mass quantities of hydrogen, the world’s cleanest energy source
Researchers at Tel Aviv University have revealed how microalgae produce hydrogen, a clean fuel of the future, and suggest a possible mechanism to jumpstart mass production of this environmentally-friendly energy source. Their results have been published in back-to-back studies in Plant Physiology and Biotechnology for Biofuels.
The research was led by Dr. Iftach Yacoby, head of TAU’s renewable energy laboratory, and Rinat Semyatich, Haviva Eisenberg, Iddo Weiner and Oded Liran, his students at the School of Plant Sciences and Food Security at TAU’s Faculty of Life Sciences.
Researchers in the past believed that algae only produce hydrogen in the course of a single microburst at dawn lasting just a few minutes. But Dr. Yacoby and his team used highly sensitive technology to discover that algae produce hydrogen from photosynthesis all day long. Armed with this discovery, the team harnessed genetic engineering to increase algae’s production of this clean energy source 400 percent.
Increasing algae’s output of hydrogen
Laboratory tests revealed that algae create hydrogen with the assistance of the enzyme hydrogenase, which breaks down when oxygen is present. The researchers discovered effective mechanisms to remove oxygen so hydrogenase can keep producing hydrogen.
“The discovery of the mechanisms makes it clear that algae have a huge underutilized potential for the production of hydrogen fuel,” said Dr. Yacoby. “The next question is how to beef up production for industrial purposes — to get the algae to overproduce the enzyme.”
Some 99% of the hydrogen produced in the US comes from natural gas. But the methods used to draw hydrogen from natural gas are toxic — and wasteful.
Answering the need for clean energy
“I grew up on a farm, dreaming of hydrogen,” said Dr. Yacoby. “Since the beginning of time, we have been using agriculture to make our own food. But when it comes to energy, we are still hunter-gatherers. Cultivating energy from agriculture is really the next revolution. There may be other ways to produce hydrogen, but this is the greenest and the only agricultural one.
“The world burns in just one year energy it took the earth over a million years to produce,” Dr. Yacoby continued. “We must stop being hunters and gatherers of energy. We must start producing clean energy — for our children and for our children’s children.”
Dr. Yacoby is now researching synthetic enzymes capable of increasing hydrogen production from microalgae to industrial levels.
A team of UK researchers, including experts from Cardiff University’s Cardiff Catalysis Institute, have shown that significant amounts of hydrogen can be unlocked from fescue grass with the help of sunlight and a cheap catalyst.
It is the first time that this method has been demonstrated and could potentially lead to a sustainable way of producing hydrogen, which has enormous potential in the renewable energy industry due to its high energy content and the fact that it does not release toxic or greenhouse gases when it is burnt.
Co-author of the study Professor Michael Bowker, from the Cardiff Catalysis Institute, said: “This really is a green source of energy.
“Hydrogen is seen as an important future energy carrier as the world moves from fossil fuels to renewable feedstocks, and our research has shown that even garden grass could be a good way of getting hold of it.”
Scientists synthesize what could be a low-cost, earth-abundant material that splits water to make hydrogen fuel.
Storing energy from sunlight or wind inside the bonds of a hydrogen (H2) molecule would let intermittent renewable energy power fuel cells, providing electricity on demand. The scalable production of H2, created by splitting apart water (H2O), depends on how well the catalysts drive the reaction. Thus far, platinum catalysts are the best, but the metal’s scarcity and cost is problematic. A layered material shows great promise as a low-cost alternative. Scientists showed that a microwave synthesis technique helps create the new material, a nanostructured molybdenum disulfide, and gives the catalyst an improved ability to produce hydrogen.
Microwave-prepared molybdenum disulfide material has the potential to be an affordable alternative to the expensive platinum catalysts that are currently used. The performance exceeds that of MoS2 materials made via other synthetic methods.
Results Suggest a More Efficient Way to Convert Solar and Wind Power to Renewable Fuels
With a combination of theory and clever, meticulous gel-making, scientists from the Department of Energy’s SLAC National Accelerator Laboratory and the University of Toronto have developed a new type of catalyst that’s three times better than the previous record-holder at splitting water into hydrogen and oxygen – the vital first step in making fuels from renewable solar and wind power.
The research, published today in the journal Science, outlines a potential way to make a future generation of water-splitting catalysts from three abundant metals – iron, cobalt and tungsten – rather than the rare, costly metals that many of today’s catalysts rely on.
“The good things about this catalyst are that it’s easy to make, its production can be very easily scaled up without any super-advanced tools, it’s consistent, and it’s very robust,” said Aleksandra Vojvodic, a SLAC staff scientist with the SUNCAT Center for Interface Science and Catalysis who led the theoretical side of the work.
Engineers at the University of California, San Diego, have created new ceramic materials that could be used to store hydrogen safely and efficiently.
The researchers have created for the first time compounds made from mixtures of calcium hexaboride, strontium and barium hexaboride. They also have demonstrated that the compounds could be manufactured using a simple, low-cost manufacturing method known as combustion synthesis.
The work is at the proof of concept stage and is part of a $1.2 million project funded by the National Science Foundation, a collaboration between UC San Diego, Alfred University in upstate New York and the University of Nevada, Reno. The manufacturing process for the ceramics is faster and simpler than traditional methods used to manufacture these types of materials. The researchers presented their work in March 2014 at the third International Symposium on Nanoscience and Nanomaterials in Mexico.
New formula for fast, abundant H2 production may help power fuel cells, helps explain expansive chemical-eating microbial communities of the deep
Scientists in Lyon, a French city famed for its cuisine, have discovered a quick-cook recipe for copious volumes of hydrogen (H2).
The breakthrough suggests a better way of producing the hydrogen that propels rockets and energizes battery-like fuel cells. In a few decades, it could even help the world meet key energy needs — without carbon emissions contributing to the greenhouse effect and climate change.
It also has profound implications for the abundance and distribution of life, helping to explain the astonishingly widespread microbial communities that dine on hydrogen deep beneath the continents and seafloor.
Describing how to greatly speed up nature’s process for producing hydrogen will be a highlight among many presentations by Deep Carbon Observatory (DCO) experts at the American Geophysical Union’s annual Fall Meeting in San Francisco Dec. 9 to 13.
The DCO is a global, 10-year international science collaboration unraveling the mysteries of Earth’s inner workings — deep life, energy, chemistry, and fluid movements.
Muriel Andreani, Isabelle Daniel, and Marion Pollet-Villard of University Claude Bernard Lyon 1 discovered the quick recipe for producing hydrogen:
In a microscopic high-pressure cooker called a diamond anvil cell (within a tiny space about as wide as a pencil lead), combine ingredients: aluminum oxide, water, and the mineral olivine. Set at 200 to 300 degrees Celsius and 2 kilobars pressure — comparable to conditions found at twice the depth of the deepest ocean. Cook for 24 hours. And voilà.
Dr. Daniel, a DCO leader, explains that scientists have long known nature’s way of producing hydrogen. When water meets the ubiquitous mineral olivine under pressure, the rock reacts with oxygen (O) atoms from the H2O, transforming olivine into another mineral, serpentine — characterized by a scaly, green-brown surface appearance like snake skin. Olivine is a common yellow to yellow-green mineral made of magnesium, iron, silicon, and oxygen.
The process also leaves hydrogen (H2) molecules divorced from their marriage with oxygen atoms in water.
The novelty in the discovery, quietly published in a summer edition of the journal American Mineralogist, is how aluminum profoundly accelerates and impacts the process.
Finding the reaction completed in the diamond-enclosed micro space overnight, instead of over months as expected, left the scientists amazed. The experiments produced H2 some 7 to 50 times faster than the natural “serpentinization” of olivine.
Over decades, many teams looking to achieve this same quick hydrogen result focused mainly on the role of iron within the olivine, Dr. Andreani says. Introducing aluminum into the hot, high-pressure mix produced the eureka moment.
Dr. Daniel notes that aluminum is Earth’s 5th most abundant element and usually is present, therefore, in the natural serpentinization process. The experiment introduced a quantity of aluminum unrealistic in nature.
Jesse Ausubel, of The Rockefeller University and a founder of the DCO program, says current methods for commercial hydrogen production for fuel cells or to power rockets “usually involve the conversion of methane (CH4), a process that produces the greenhouse gas carbon dioxide (CO2) as a byproduct. Alternatively, we can split water molecules at temperatures of 850 degrees Celsius or more — and thus need lots of energy and extra careful engineering.”
“Aluminum’s ability to catalyze hydrogen production at a much lower temperature could make an enormous difference. The cost and risk of the process would drop a lot.”
“Scaling this up to meet global energy needs in a carbon-free way would probably require 50 years,” he adds. “But a growing market for hydrogen in fuel cells could help pull the process into the market.”
“We still need to solve problems for a hydrogen economy, such as storing the hydrogen efficiently as a gas in compact containers, or optimizing methods to turn it into a metal, as pioneered by Russell Hemley of the Carnegie Institution’s Geophysical Laboratory, another co-founder of the DCO.”
Deep energy, Dr. Hemley notes, is typically thought of in terms of geothermal energy available from heat deep within Earth, as well as subterranean fluids that can be burned for energy, such as methane and petroleum. What may strike some as new is that there is also chemical energy in the form of hydrogen produced by serpentinization.
At the time of the AGU Fall Meetings, Dr. Andreani will be taking a lead role with Javier Escartin of the Centre National de la Recherche Scientifique in a 40-member international scientific exploration of fault lines along the Mid-Atlantic Ridge. It is a place where the African and American continents continue to separate at an annual rate of about 20 mm (1.5 inches) and rock is forced up from the mantle only 4 to 6 km (2.5 to 3.7 miles) below the thin ocean floor crust. The study will advance several DCO goals, including the mapping of world regions where deep life-supporting H2 is released through serpentinization.
Aboard the French vessel Pourquoi Pas?, using a deep sea robot from the French Research Institute for Exploitation of the Sea (IFREMER), and a deep-sea vehicle from Germany’s Leibniz Institute of Marine Sciences (GEOMAR), the team includes researchers from France, Germany, USA, Wales, Spain, Norway and Greece (more information: odemar.weebly.com).
Notes Dr. Daniel, until now it has been a scientific mystery how the rock + water + pressure formula produces enough hydrogen to support the chemical-loving microbial and other forms of life abounding in the hostile environments of the deep.
With the results of the experiment in France, “for the first time we understand why and how we have H2 produced at such a fast rate. When you take into account aluminum, you are able to explain the amount of life flourishing on hydrogen,” says Dr. Daniel.
Indeed, DCO scientists hypothesize that hydrogen was what fed the earliest life on primordial planet Earth — first life’s first food.
And, she adds: “We believe the serpentinization process may be underway on many planetary bodies — notably Mars. The reaction may take one day or one million years but it will occur whenever and wherever there is some water present to react with olivine — one of the most abundant minerals in the solar system.”
Enigmatic evidence of a deep subterranean microbe network
Meanwhile, the genetic makeup of Earth’s deep microbial life is being revealed through DCO research underway by Matt Schrenk of Michigan State University, head of DCO’s “Rock-Hosted Communities” initiative, Tom McCollom of the University of Colorado, Boulder, Steve D’Hondt of the University of Rhode Island, and many other associates.
At AGU, they will report the results of deep sampling from opposite sides of the world, revealing enigmatic evidence of a deep subterranean microbe network.
Using DNA, researchers are finding hydrogen-metabolizing microbes in rock fractures deep beneath the North American and European continents that are highly similar to samples a Princeton University group obtained from deep rock fractures 4 to 5 km (2.5 to 3 miles) down a Johannesburg-area mine shaft. These DNA sequences are also highly similar to those of microbes in the rocky seabeds off the North American northwest and northeastern Japanese coasts.
“Two years ago we had a scant idea about what microbes are present in subsurface rocks or what they eat,” says Dr. Schrenk. “Since then a number of studies have vastly expanded that database. We’re getting this emerging picture not only of what sort of organisms are found in these systems but some consistency between sites globally — we’re seeing the same types of organisms everywhere we look.”
“It is easy to understand how birds or fish might be similar oceans apart, but it challenges the imagination to think of nearly identical microbes 16,000 km apart from each other in the cracks of hard rock at extreme depths, pressures, and temperatures” he says.
“In some deep places, such as deep-sea hydrothermal vents, the environment is highly dynamic and promotes prolific biological communities,” says Dr. McCollom. “In others, such as the deep fractures, the systems are isolated with a low diversity of microbes capable of surviving such harsh conditions.”
“The collection and coupling of microbiological and geochemical data made possible through the Deep Carbon Observatory is helping us understand and describe these phenomena.”
How water behaves deep within Earth’s mantle
Among other major presentations, DCO investigators will introduce a new model that offers new insights into water / rock interactions at extreme pressures 150 km (93 miles) or more below the surface, well into Earth’s upper mantle. To now, most models have been limited to 15 km, one-tenth the depth.
“The DCO gives a happy twist to the phrase ‘We are in deep water’,” says researcher Dimitri Sverjensky of Johns Hopkins University, Baltimore MD.
Dr. Sverjensky’s work, accepted for publication by the Elsevier journal Geochimica et Cosmochimica Acta, is expected to revolutionize understanding of deep Earth water chemistry and its impacts on subsurface processes as diverse as diamond formation, hydrogen accumulation, the transport of diverse carbon-, nitrogen- and sulfur-fed species in the mantle, serpentinization, mantle degassing, and the origin of Earth’s atmosphere.
In deep Earth, despite extreme high temperatures and pressures, water is a fluid that circulates and reacts chemically with the rocks through which it passes, changing the minerals in them and undergoing alteration itself — a key agent for transporting carbon and other chemical elements. Understanding what water is like and how it behaves in Earth’s deep interior is fundamental to understanding the deep carbon cycle, deep life, and deep energy.
This water-rock interaction produces valuable ore deposits, creates the chemicals on which deep life and deep energy depend, influences the generation of magma that erupts from volcanoes — even the occurrence of earthquakes. Humanity gets glimpses of this water in hot springs.
Says Dr. Sverjensky: “The new model may enable us to predict water-rock interaction well into Earth upper mantle and help visualize where on Earth H2 production might be underway.”