Carbon dioxide can be stored as a solid, glass-like substance.

European researchers may have found a new way to capture and store CO2, by transforming it into a solid, glass-like substance.

The team of chemists and physicists from across Europe discovered this new form of CO2 by exposing ice crystals of the gas to high pressures (up to 48GPa). Using various analytical techniques, the researchers found that this caused the CO2 to transform from its molecular state into an amorphous solid, which they termed a-carbonia.

This finding further confirms that, at high temperatures and pressures, carbon behaves similarly to the other elements in its group of the periodic table, such as silicon and germanium. Both these elements form solid oxides, such as silicon dioxide (silica), whereas carbon naturally forms gaseous oxides. 

In 1999, researchers from Lawrence Livermore National Laboratory, California, US, showed that CO2 could be transformed into a crystalline solid, similar to silica quartz, under the right conditions. Building on this research, the European researchers have now shown that CO2 can also be transformed into a glass-like solid, which appears to be harder than silica glass.

The team is now attempting to study a-carbonia at even higher pressures and is exploring potential applications. ’Mixtures of a-carbonia and silica could, in principle, be synthesised,’ team member Federico Gorelli at the European Laboratory for Non-Linear Spectroscopy, Florence, Italy, told Chemistry World, ’making new amorphous glasses, which would be very hard and stiff and likely stable at room conditions.’ This glass could find use as a hard coating for tiny electronic and photonic devices, he said.

Himanshu Jain, a professor of materials science and engineering at Lehigh University, US, says that this work ’is a significant contribution to the development of inorganic oxide glasses’. He also predicts that it will lead to the emergence of a new field of carbonate network glass and the development of novel glasses with superior properties.

Jon Evans