Australian scientists have developed a catalyst that converts carbon dioxide from the air into synthetic natural gas using solar energy.
The research, carried out at the University of Adelaide in collaboration with CSIRO, Australia’s national agency for scientific research, could validate a process that has the potential to replace fossil fuels and continue to use existing carbon-based fuel technologies without increasing atmospheric CO2.
The catalyst drives the process of combining CO2 with hydrogen to produce methane and water.
“Capturing carbon from the air and utilising it for industrial processes is one strategy for controlling CO2 emissions and reducing the need for fossil fuels,” said University of Adelaide PhD candidate Renata Lippi, first author of the research published in the Journal of Materials Chemistry A.
“But for this to be economically viable, we need an energy efficient process that utilises CO2 as a carbon source. Research has shown that the hydrogen can be produced efficiently with solar energy. But combining the hydrogen with CO2 to produce methane is a safer option than using hydrogen directly as an energy source and allows the use of existing natural gas infrastructure.
“The main sticking point, however, is the catalyst – a compound needed to drive the reaction because CO2 is usually a very inert…chemical.”
The catalyst was synthesised using metal-organic frameworks, which allow precise spatial control of the chemical elements.
“The catalyst discovery process involved the synthesis and screening of more than one hundred materials. With the help of CSIRO’s rapid catalyst testing facility we were able to test all of them quickly allowing the discovery to be made in a much shorter period of time,” said Dr Danielle Kennedy, AIM Future Science Platform Director with CSIRO. “We hope to continue collaborating with the University of Adelaide to allow renewable energy and hydrogen to be applied to chemical manufacturing by Australian industry.”
Other catalysts have presented issues around poor CO2 conversion, unwanted carbon-monoxide production, catalyst stability, low methane production rates and high reaction temperatures.
This new catalyst is said to produce almost pure methane from CO2. Carbon-monoxide production has reportedly been minimised and stability is high under continuous reaction for several days and after shutdown and exposure to air.
Only a small amount of the catalyst is needed for high production of methane which increases economic viability. The catalyst also operates at mild temperatures and low pressures, making solar thermal energy possible.
“What we’ve produced is a highly active, highly selective (producing almost pure methane without side products) and stable catalyst that will run on solar energy,” said project leader Prof Christian Doonan, director of the University’s Centre for Advanced Nanomaterials. “This makes carbon neutral fuel from CO2 a viable option.”