US scientists find new way to convert CO2 to green fuel

Unexpected discovery that produces ethanol could be a “building block” towards creating a low-carbon energy system.

Indian man takes a morning walk in a public garden surrounded by the smog
Many countries are switching to ethanol from fossil fuels, blamed for the majority of harmful gas emissions [EPA]

US scientists say they have stumbled upon an economically practical and highly efficient way of converting a greenhouse gas largely blamed for global warming into an environmentally friendly fuel – a development that could boost the renewable energy industry.

Researchers from the Oak Ridge National Laboratory in the US state of Tennessee last month announced they “serendipitously” developed a catalyst that transformed carbon dioxide (CO2), a main greenhouse gas, into high yields of ethanol – without the use of rare and expensive elements such as platinum.

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Ethanol, produced from organic matter such as corn or sugar, is the most widely used biofuel in the world.

Many countries, including the United States and China, are increasingly attempting to make ethanol a mainstream fuel while cutting the use of fossil fuels, which are blamed for the vast majority of harmful gas emissions driving climate change.

According to the Oak Ridge scientists, tiny particles of carbon and copper, as well as nitrogen and electrical currents, helped trigger a chemical reaction that unexpectedly converted CO2 into ethanol. 

The researchers had been attempting to discover a series of chemical reactions that would revert carbon dioxide – a byproduct of fuel consumption – back to a fuel. They found the first step in the process not only worked, but even cheaply and efficiently produced ethanol.

“We’re taking carbon dioxide, a waste product of combustion, and we’re pushing that combustion reaction backwards with very high selectivity to a useful fuel,” Adam Rondinone, a lead author of the team’s study published in the online journal ChemistrySelect, said in a press release.

“Ethanol was a surprise – it’s extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst.”

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The researchers plan to conduct further tests to determine how their conversion technique could be used to produce ethanol on an industrial scale.

The breakthrough announcement, released on October 12, also suggested the process could be combined with other renewables, such as solar or wind power, to more efficiently harness those energy sources.

Excess electricity produced by wind and solar is often lost when it is stored in batteries. 

However, by applying the new discovery, this excess electricity could be used to produce ethanol to power solar factories and turbines when there’s insufficient sun and wind, the scientists say.

“This could help to balance a grid supplied by intermittent renewable sources,” Rondinone said. 

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Dr Jeremy Martin – a senior scientist and fuels expert from the Union of Concerned Scientists, a science-based advocacy organisation – told Al Jazeera the Oak Ridge team’s discovery could be a “building block” towards creating a low-carbon energy system.

“This work is building the foundation for a chemical industry that runs on electricity and CO2, which can help us build a zero-carbon economy. Improving yield and efficiency and developing catalysts that do not require rare elements is critical to scaling these processes up cost effectively,” said Martin.

“The contribution of such a process to reducing pollution depends on having abundant clean electricity. We are making progress in this area, but we still have a lot of work to do.”

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Source: Al Jazeera