(Press-News.org) Published in the journal Nature, the discovery could revolutionise fuel cells and other hydrogen-based technologies as they require a barrier that only allow protons - hydrogen atoms stripped off their electrons - to pass through.
In addition, graphene membranes could be used to sieve hydrogen gas out of the atmosphere, where it is present in minute quantities, creating the possibility of electric generators powered by air.
One-atom thick material graphene, first isolated and explored in 2004 by a team at The University of Manchester, is renowned for its barrier properties, which has a number of uses in applications such as corrosion-proof coatings and impermeable packaging.
For example, it would take the lifetime of the universe for hydrogen, the smallest of all atoms, to pierce a graphene monolayer.
Now a group led by Sir Andre Geim tested whether protons are also repelled by graphene. They fully expected that protons would be blocked, as existing theory predicted as little proton permeation as for hydrogen.
Despite the pessimistic prognosis, the researchers found that protons pass through the ultra-thin crystals surprisingly easily, especially at elevated temperatures and if the films were covered with catalytic nanoparticles such as platinum.
The discovery makes monolayers of graphene, and its sister material boron nitride, attractive for possible uses as proton-conducting membranes, which are at the heart of modern fuel cell technology. Fuel cells use oxygen and hydrogen as a fuel and convert the input chemical energy directly into electricity. Without membranes that allow an exclusive flow of protons but prevent other species to pass through, this technology would not exist.
Despite being well-established, fuel-cell technology requires further improvements to make it more widely used. One of the major problems is a fuel crossover through the existing proton membranes, which reduces their efficiency and durability.
The University of Manchester research suggests that the use of graphene or monolayer boron nitride can allow the existing membranes to become thinner and more efficient, with less fuel crossover and poisoning. This can boost competitiveness of fuel cells.
The Manchester group also demonstrated that their one-atom-thick membranes can be used to extract hydrogen from a humid atmosphere. They hypothesise that such harvesting can be combined together with fuel cells to create a mobile electric generator that is fuelled simply by hydrogen present in air.
Marcelo Lozada-Hidalgo, a PhD student and corresponding author of this paper, said: "When you know how it should work, it is a very simple setup. You put a hydrogen-containing gas on one side, apply small electric current and collect pure hydrogen on the other side. This hydrogen can then be burned in a fuel cell.
"We worked with small membranes, and the achieved flow of hydrogen is of course tiny so far. But this is the initial stage of discovery, and the paper is to make experts aware of the existing prospects. To build up and test hydrogen harvesters will require much further effort."
Dr Sheng Hu, a postdoctoral researcher and the first author in this work, added: "It looks extremely simple and equally promising. Because graphene can be produced these days in square metre sheets, we hope that it will find its way to commercial fuel cells sooner rather than later".
INFORMATION:
The work is an international collaboration involving groups from China and the Netherlands who supported theoretical aspects of this research. Marcelo Lozada-Hidalgo is funded by a PhD studentship programme between the National Council of Science and Technology of Mexico and The University of Manchester.
NGC 3532 is a bright open cluster located some 1300 light-years away in the constellation of Carina(The Keel of the ship Argo). It is informally known as the Wishing Well Cluster, as it resembles scattered silver coins which have been dropped into a well. It is also referred to as the Football Cluster, although how appropriate this is depends on which side of the Atlantic you live. It acquired the name because of its oval shape, which citizens of rugby-playing nations might see as resembling a rugby ball.
This very bright star cluster is easily seen with the naked eye ...
Jülich, 26 November 2014 - In metals such as copper or aluminium, so-called conduction electrons are able to move around freely, in the same way as particles in a gas or a liquid. If, however, impurities are implanted into the metal's crystal lattice, the electrons cluster together in a uniform pattern around the point of interference, resembling the ripples that occur when a stone is thrown into a pool of water. Scientists in Jülich have, with the help of computer simulations, now discovered a combination of materials that strengthens these Friedel oscillations ...
The Luxembourg Centre for Systems Biomedicine (LCSB) has succeeded for the first time in describing the complex relationships within an ecosystem in unprecedented detail. For their work, carried out in collaboration with US and Luxembourg partners, their model ecosystem was a "biological wastewater treatment plant". In it live numerous species of bacteria which are involved in the wastewater purification process.
LCSB director Prof. Dr. Rudi Balling stresses the medical importance of these research efforts: "Bacterial ecosystems also play a major role in our health. ...
Although the van der Waals force was discovered around 150 years ago, it is still difficult to quantify when predicting the behaviour of solids, liquids, and molecules. Precise measurements were only possible up to now for single atoms or macroscopic objects. However, the van der Waals forces are particularly important at intermediate size, where they crucially co-determine the behaviour of complex molecules, such as biomolecules and proteins. They are also responsible for the functioning of certain adhesives and are the reason why geckos can adhere so amazingly well to ...
This news release is available in French. The way people with autism spectrum disorder (ASD) gather information - not the judgement process itself - might explain why they gain different perceptions from peoples' faces, according to a new study from Hôpital Rivière-des-Prairies and the University of Montreal. "The evaluation of an individual's face is a rapid process that influences our future relationship with the individual," said Baudouin Forgeot d'Arc, lead author of the study. "By studying these judgments, we wanted to better understand how people with ...
The precise movements of a young hammerhead shark have been tracked for the first time and are published in the open access journal Animal Biotelemetry. The study, which ran over a 10-month period, reveals important gaps in current efforts to protect these endangered sharks and suggests key locations that should be protected to help the survival of the species.
Hammerhead sharks, which have recently received new protections from the UN Convention on the Conservation of Migratory Species of Wild Animals, are experiencing drastic population declines in excess of 90% in ...
The expression of a gene involved in female birds' color vision is linked to the evolution of colorful plumage in males, reports a new study from the University of Chicago. The findings, published Nov. 26 in the Proceedings of the Royal Society B, confirm the essential role of female color perception in mate selection and sexual dimorphism.
"This is the first time an aspect of the visual system in birds has been directly associated with plumage evolution," said Natasha Bloch, PhD, who authored the study while a graduate student in ecology & evolution at the University ...
Deaf teenagers have better reading skills if they were identified as deaf by the time they were nine months old, research from the University of Southampton has shown.
The Southampton team has been studying the development of a group of children who were identified with permanent childhood hearing impairment (PCHI) at a very early age in a pilot screening programme conducted in Southampton and London in the 1990s.
Follow up assessments when the children were aged eight showed those who were screened at birth had better language skills than those children who were not ...
Rheumatic heart disease (RHD) - the most common acquired heart disease in children in many countries of the world - is being neglected and poorly treated, according to new findings from the Global Rheumatic Heart Disease Registry (the REMEDY study), published online today (Wednesday) in the European Heart Journal [1].
RHD accounts for up to 1.4 million deaths every year, with the highest numbers of people affected by it and dying occurring in low and middle-income countries. It is triggered by rheumatic fever (RF) that can be prevented and controlled. RF is preceded by ...
The potential to quickly diagnose children with type 1 diabetes before the onset of serious illness could be achieved using a simple, non-invasive breath test, according to new research published today.
In one of the most comprehensive breath-based studies of children with type 1 diabetes performed to date, a team of researchers from Oxford, UK have linked a sweet-smelling chemical marker in the breath with a build-up of potentially harmful chemicals in the blood that accumulate when insulin levels are low.
It is hoped these results--linking an increased level of breath ...
