Australian scientists have developed an efficient catalyst that converts carbon dioxide into synthetic natural gas in a ‘clean’ process using solar energy, paving the way for carbon neutral fuel.
The study by researchers, including those from University of Adelaide in Australia, could make viable a process that has enormous potential to replace fossil fuels and continue to use existing carbon-based fuel technologies without increasing atmospheric CO2.
The catalyst effectively drives the process of combining CO2 with hydrogen to produce methane (the main component of the fossil fuel natural gas) and water.
Currently, natural gas is one of the main fuels used for industrial activities.
“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.
“But for this to be economically viable, we need an energy efficient process that utilises CO2 as a carbon source,” said Lippi, first author of the study published in the Journal of Materials Chemistry A.
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 or unreactive chemical,” Lippi said.
The catalyst was synthesised using porous crystals called 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,” said Danielle Kennedy from Commonwealth Scientific and Industrial Research Organisation (CSIRO).
With other catalysts there have been issues around poor CO2 conversion, unwanted carbon-monoxide production, catalyst stability, low methane production rates and high reaction temperatures.
The new catalyst efficiently produces almost pure methane from CO2. Carbon-monoxide production has been minimised and stability is high under both 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 have 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 Professor Christian Doonan.