Researchers at William Marsh Rice University, in Texas, have managed to cost-effectively recycle CO2 into formic acid – the basis of a type of fuel cell. The work has created a working proof-of-concept for tackling climate change. The researchers, part-funded by US Department of Energy Office of Science User Facilities, are now ready to re-tool the equipment to produce liquid fuels like ethanol and propanol which could be used to power cars.
Turning CO2 into fuel is not a new idea but previous attempts have been very energy inefficient resulting in more carbon dioxide rather than less.
But the new technique is considered a game changer and, in tandem with renewable electricity, provides a commercially viable way of turning free CO2 in the atmosphere into potentially lucrative fuel, researchers say.
Chemical and biomolecular engineer Haotian Wang, who led the team developing the catalytic reactor, said: “The big picture is that carbon dioxide reduction is very important for its effect on global warming as well as for green chemical synthesis.
“If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it.”
Mr Wang added formic acid produced by traditional carbon dioxide devices needs costly and energy-intensive purification steps but that his technique for direct production of pure formic acid solutions would help promote commercial carbon dioxide conversion technologies.
He said even the production of formic acid via the process was a huge step forward and added: “Formic acid is an energy carrier. It is a fuel-cell fuel that can generate electricity and emit carbon dioxide — which you can grab and recycle again.
“It is also fundamental in the chemical engineering industry as a feedstock for other chemicals, and a storage material for hydrogen that can hold nearly 1,000 times the energy of the same volume of hydrogen gas, which is difficult to compress. That is currently a big challenge for hydrogen fuel-cell cars.”
The new Rice University approach to turning CO2 into fuel eliminates the need for salt in the reaction.
The lab was able to generate formic acid continuously for 100 hours with little noticeable degradation to the components of the reactor. The findings were considered proof that the technology could be scaled up to commercial and industrial levels.
Dr Chuan said:“Next, we will focus on the production of pure C2+ liquid fuels — ethanol and propanol — which is much more energy-dense and valuable than C1 fuels, such as formic acid, via catalyst design and CO2RR system optimization.”
The paper called “Continuous production of pure liquid fuel solutions via electrocatalytic CO2 reduction using solid-electrolyte devices,” is published in the journal Nature Energy.