Capturing carbon dioxide before it reaches the atmosphere is a key part of our global strategy to combat climate change. In an effort to find ways that could help us do that efficiently, scientists at RMIT have developed a method that quickly converts carbon dioxide into solid carbon, which can later be safely stored or used to create other materials.

The process involves bubbling CO2 up through a tube of liquid metal called Eutectic Gallium-Indium (EGaIn), which is exposed to temperatures between 100 and 120°C (212 and 248°F). As CO2 is injected into the mix, the molecules of the gas split into flakes of solid carbon that rise to the surface, making them easy to collect.

A particularly important aspect of the design is that the technology can be easily integrated into the source of emissions. The reaction occurs rapidly and efficiently, while the temperature required is relatively low and could potentially be supplied by renewables.

The resulting solid carbon can then be easily transported and stored, without risk of leakage. This could then be either buried for storage or, even better, used for other industrial applications, such as making construction materials.

The team now plans to scale up the system to a modular prototype about the size of a shipping container and put it to test at a carbon-emitting facility.

Source study: Energy & Environmental Science – Direct conversion of CO2 to solid carbon by Ga-based liquid metals