Methane is a potent greenhouse gas, albeit with a relatively short “life”. Over a 20-year period, the estimated global warming potential of methane emissions is 84 to 87 times that of carbon dioxide. Methane concentrations in the global atmosphere have been relatively stable over the past few hundred thousand years, but have increased rapidly since the 1750s and the beginning of the Industrial Revolution.
It comes from just about anywhere – to quote NASA Earth Observatory writer Adam Voiland: “You can find this odorless, transparent gas for miles below the Earth’s surface and miles above. Methane comes from swamps and rivers. Effervescent from volcanic gas, erupted from volcanoes, rose from wildfires, and oozes from the guts of cows and termites (it’s made by microorganisms). Human settlements are awash with this gas. Methane emerges from natural gas, oil wells and It leaks silently from pipes and from coal mines. It’s generated in landfills, sewage treatment plants and rice fields.”
According to the International Energy Agency (IEA), oil production currently accounts for about 40% of methane emissions from the entire oil and gas industry. Oil companies are not interested in methane escaping during oil drilling; it is not very economical to introduce it into natural gas infrastructure, and it is also dangerous and inconvenient to store, although it can be catalytically converted into more usable liquid fuels such as methanol, but the process is too expensive to consider.
As long as there are oil wells, this excess methane needs to be disposed of. UNSW researchers say they have made a major breakthrough in methane binding, which opens the door to more efficient, effective and hopefully affordable catalytic conversion.
So far, the question has been how to hold methane molecules in place so they can be studied. According to UNSW, researchers have been able to use metal-methane complexes to immobilize methane in a molecular ‘tweezer’ – but only for a few microseconds. That’s a far cry from the minutes it takes to properly analyze such molecules in an NMR spectroscopy facility.
Using computational models to try to predict whether other metals might bind to methane for longer periods of time, the UNSW research team pointed to osmium – a platinum metal and the densest element found in nature. The group continued to experiment with impressive results.
“We’ve found that methane, which is normally inert, interacts with what’s in the center of the osmium metal to form a relatively stable osmium-methane complex,” said James Watson, lead author of the new study. “Our complex has an effective half-life of about 13 hours.”
“That means half of the complex takes 13 hours to break down,” he continued. “This stability, coupled with the relatively long lifetime of this complex, allows us to deeply analyze the structure, formation and reactivity of this class of (osmium) complexes, and helps to design potential conversions of methane into More catalysts for the synthesis of useful compounds provide information.”
Osmium is one of the rarest elements on Earth, but that can’t possibly be a factor here. Importantly, these osmium complexes allow for the first time that kind of in-depth molecular analysis, which should lead to new catalytic processes using cheaper and more available elements that can quickly and economically convert methane into liquid fuels.
“One way to convert methane into a liquid fuel is through the use of catalysts containing transition metal elements,” explains Associate Professor Graham Ball, co-author of the study. “Not only is (liquid fuel) much more convenient and safer than storing gas, but energy costs are also much lower.”
He continued: “Liquid fuels are easier to transport and integrate easily into our existing fuel infrastructure – E10 gasoline already contains 10% ethanol. For example, if there were efficient, commercially viable ways to convert methane to methanol , which will also motivate us to retain methane for conversion and avoid unintended burning, reducing the overall use of fossil fuels and damaging emissions. We hope our findings will inform the design of the next generation of more efficient catalysts that can Commercially viable.”
Now, no liquid hydrocarbon fuel, including methanol, can be considered environmentally friendly because burning it would result in carbon dioxide emissions. But if it’s going to be burnt, like the huge amount of methane that’s burning right now, it might do a thing for someone instead of being wasted entirely. It’s an interim step in humanity’s fight to clean up the atmosphere, but it has the potential to have a huge impact if further research proves to be as positive as the team expects.
The study was published innatural chemistry” magazine.
