Nature-Inspired Carbon Capture

By Gina Wynn

Researchers at Tokyo Institute of Technology (Tokyo Tech) in Japan have taken cues from nature to rethink the possibilities for capturing carbon dioxide from the atmosphere to combat its threat to our environment and to public health.

It is no secret that high levels of heat-trapping carbon dioxide in our atmosphere from the burning of fossil fuels like coal, oil and gas are contributing to climate change. For humans, exposure to too much carbon dioxide can result in adverse health effects including shortness of breath, drowsiness, dizziness, headaches, low productivity, and more.

The Technology

After decades of work, Tokyo Tech chemists have recently found success using a process called electrocatalysis to reduce the amount of carbon dioxide in gases with low carbon dioxide concentrations.

This work is significant as one of the few projects focused on improving direct capture of carbon dioxide concentrations as low as one percent. Heavy industry exhaust typically contains low levels of carbon dioxide (around 3 to 13 percent). Prior studies aimed to reduce carbon dioxide at higher levels.

Learning from Nature

The research team, led by Osamu Ishitani from the Department of Chemistry, may have been inspired by how plants have been operating since the beginning of time. Plant respiration is made possible by repurposing low concentrations of carbon dioxide in the atmosphere (about 400ppm, or 0.04 percent).

The journal Chemical Science published the study that details how the team of chemists, which included Hiromu Kumagai and Tetsuya Nishikawa, made a breakthrough with the electrocatalytic process. Electrocatalysis takes energy from one set of electrochemical reactions to accelerate another reaction.

By harnessing the capabilities of a rhenium-based catalyst, they were able to capture low-concentration carbon dioxide in the presence of triethanolamine (TEOA).

Experimental Success

According to university reports, “In a series of experiments to assess electrocatalytic activity, the researchers found that at a carbon dioxide concentration of 1 percent, the rhenium-based catalyst showed very high selectivity (94 percent) toward carbon monoxide formation.”

The team credits the efficient insertion of carbon dioxide into the rhenium-oxygen bond for the experiments’ successes. It may have also contributed to the study’s most noteworthy outcome: the technology’s ability to successfully work with particularly low concentrations of carbon dioxide.

Future Potential

Tokyo Tech’s electrocatalytic method eliminates the need for the energy-consuming condensation processes that are typically necessary for carbon capture. Current methods, like direct air capture, are also costly.

Ishitani and his colleagues hope that a scaled-up version of their electrocatalytic technology could offer a more viable, environmentally friendly option for capturing carbon from the atmosphere — helping to control climate change and making clean air available for future generations.

Fern Leaves