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.’
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.”
Cardiff University (Welsh: Prifysgol Caerdydd) is a public research university located in Cardiff, Wales, United Kingdom.
The University is composed of three colleges: Arts, Humanities and Social Sciences; Biomedical and Life Sciences; and Physical Sciences and Engineering.
Founded in 1883 as the University College of South Wales and Monmouthshire, it became one of the founding colleges of the University of Wales in 1893, and in 1999 became an independent University awarding its own degrees. It is the second oldest university in Wales. It is a member of the Russell Group of leading British research universities. The university is consistently recognised as providing high quality research-based university education and is ranked 123 of the world’s top universities by the QS World University Rankings, as well as achieving the highest student satisfaction rating in the 2013 National Student Survey for universities in Wales
The University has an undergraduate enrolment of 20,611 and a total enrolment of 27,774, making it one of the largest universities in Wales. The Cardiff University Students’ Union works to promote the interests of the student body within the University and further afield.
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Cardiff University research articles from Innovation Toronto
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Creation of first practical silicon-based laser has the potential to transform communications, healthcare and energy systems
A group of researchers from the UK, including academics from Cardiff University, has demonstrated the first practical laser that has been grown directly on a silicon substrate.
It is believed the breakthrough could lead to ultra-fast communication between computer chips and electronic systems and therefore transform a wide variety of sectors, from communications and healthcare to energy generation.
The EPSRC-funded UK group, led by Cardiff University and including researchers from UCL and the University of Sheffield, have presented their findings in the journal Nature Photonics.
Silicon is the most widely used material for the fabrication of electronic devices and is used to fabricate semiconductors, which are embedded into nearly every device and piece of technology that we use in our everyday lives, from smartphones and computers to satellite communications and GPS.
Electronic devices have continued to get quicker, more efficient and more complex, and have therefore placed an added demand on the underlining technology.
Researchers have found it increasingly difficult to meet these demands using conventional electrical interconnects between computer chips and systems, and have therefore turned to light as a potential ultra-fast connector.
Whilst it has been difficult to combine a semiconductor laser – the ideal source of light – with silicon, the UK group have now overcome these difficulties and successfully integrated a laser directly grown onto a silicon substrate for the very first time.
Professor Huiyun Liu, who led the growth activity, explained that the 1300 nm wavelength laser has been shown to operate at temperatures of up to 120°C and for up to 100,000 hours.
Professor Peter Smowton, from Cardiff University’s School of Physics and Astronomy, said: “Realising electrically-pumped lasers based on Si substrates is a fundamental step towards silicon photonics.
“The precise outcomes of such a step are impossible to predict in their entirety, but it will clearly transform computing and the digital economy, revolutionise healthcare through patient monitoring, and provide a step-change in energy efficiency.
“Our breakthrough is perfectly timed as it forms the basis of one of the major strands of activity in Cardiff University’s Institute for Compound Semiconductors and the University’s joint venture with compound semiconductor specialists IQE.”
Professor Alwyn Seeds, Head of the Photonics Group at University College London, said: “The techniques that we have developed permit us to realise the Holy Grail of silicon photonics – an efficient and reliable electrically driven semiconductor laser directly integrated on a silicon substrate. Our future work will be aimed at integrating these lasers with waveguides and drive electronics leading to a comprehensive technology for the integration of photonics with silicon electronics.”
An international group of researchers has synthesized an extremely rare mineral and used it as a catalyst precursor to improve two reactions that are of great importance to the chemical industry.
Using a technique called supercritical anti-solvent precipitation (SAS), the group produced large quantities of highly pure georgeite, a disordered copper-hydroxycarbonate that is found naturally only in Australia and in an old copper mine in Snowdonia, Wales.
The group tested georgeite’s catalytic activity against commercial catalysts that have been used for a half-century in the water-gas shift reaction, in which water reacts with carbon dioxide to produce hydrogen.
“We found that the georgeite was a superb catalyst for the water-gas shift reaction and had a much higher performance compared to the commercial catalyst currently used in industry,” said Graham Hutchings, director of the Cardiff Catalysis Institute at Cardiff University in Wales.
Hydrogen is an essential ingredient in the manufacture of methanol and ammonia, which form the basis of hundreds of chemicals, including fuels, plastics, paints, solvents and fertilizer.
The group also found that their synthesized georgeite material was highly effective in carrying out methanol synthesis, in which CO2 and hydrogen are combined to make methanol.
“Catalysts based on copper-zinc oxide minerals have been used for many decades to catalyze both of these reactions,” said Christopher J. Kiely, professor of materials science and chemical engineering at Lehigh. “Our georgeite-derived materials represent the first time something potentially better has come along.”
The group reported its findings this week in Nature magazine in an article titled “Stable amorphous georgeite as a precursor to a high-activity catalyst.” The article was authored by researchers from Cardiff, Lehigh, the UK Catalysis Hub, University College London, Diamond Light Source in the United Kingdom, the University of Liverpool, the Technical University of Denmark, and Johnson Matthey, a multinational chemicals and sustainable technologies company headquartered in Royston, UK.
A readily synthesized precursor
Georgeite belongs to a family of minerals called copper hydroxycarbonates that are widely used as catalyst precursors in the chemical industry. Scientists are familiar with other hydroxycarbonates, such as malachite, aurichalcite and rosasite, but know little about georgeite because of its extreme rarity, low purity, instability and highly disordered nature.
Chemists at the Cardiff Catalysis Institute synthesized georgeite using SAS, in which CO2 is subjected to conditions of heat and pressure that put it into a supercritical state where it displays the characteristics of both a liquid and a gas.
“Supercritical CO2 expands like a gas to fill up a volume while retaining the viscosity of a liquid,” said Kiely. “It’s an unusual state of matter and has the ability when bubbled through a solution to make solids precipitate out very quickly. Supercritical CO2 is also used for processes such as decaffeinating coffee.”
Chemists at the Cardiff Catalysis Institute synthesized georgeite by dissolving a copper-zinc-oxide precursor in an organic solvent and then passing supercritical CO2 through the solvent to rapidly precipitate out the georgeite.
“[We have shown] that stable georgeite can be readily synthesized using supercritical carbon dioxide as an anti-solvent in a precipitation process,” the researchers wrote in Nature. “The synthetic georgeite materials are precursors to highly active methanol synthesis and superior water gas shift catalysts as compared to those currently prepared from crystalline malachite.
“This new route to georgeite will open up new opportunities for the use of this important material in a number of applications.”
A crucial role for crystals
Researchers at Lehigh and the Technical University of Denmark used advanced electron microscopy techniques to structurally characterize the georgeite and determine why it produces such high performing catalysts.
“We looked at the georgeite with an aberration-corrected STEM [scanning transmission electron microscope],” said Kiely. “Georgeite had been thought to be completely amorphous, that is, more like glass than a crystalline mineral. We found that georgeite is in fact about 90 percent amorphous but has 2-nanometer crystals of copper oxide embedded within it.
“The actual catalyst is not a pure georgeite material,” said Kiely. “The georgeite, when deliberately doped with some zinc, is really a precursor to the active catalyst. It needs to be calcined, or heated in air, and then reduced in hydrogen gas before it can be used as a catalyst.”
To learn what happened during calcination and reduction, the group turned to colleagues at the Technical University of Denmark, which has an environmental transmission electron microscope (ETEM).
“The ETEM is a very specialized instrument,” said Kiely. “The beauty of it is that you can take a zincian georgeite precursor, heat it up in the microscope under a gaseous environment and then watch how it changes during the process. This allowed us to dynamically view the precursor material as it transformed into the active catalyst.
“What we saw with the ETEM is that when calcined zincian georgeite is reduced in hydrogen, it forms very tiny copper particles intimately supported on nanoscopic zinc oxide grains. This special nanostructure is responsible for the good catalytic properties.
“We compared this with the conventional catalyst materials derived from a crystalline malachite, and found that our zincian georgeite results in a much finer microstructure, with smaller copper and zinc oxide particles, which ultimately contributes to the superior catalytic performance.”
The synthetic zincian georgeite catalyst, said Kiely, has the additional advantage that its composition can be easily tuned, or altered, by adjusting the ratio of copper atoms to zinc atoms in the starting solution. It can also be made in large quantities.