Chemists at Tokyo Institute of Technology (Tokyo Tech) propose an innovative way to achieve carbon capture using a rhenium-based electrocatalytic system that is capable of reducing low-concentration CO 2 (even 1%) with high selectivity and durability, which is a new potential technology to enable direct utilization of CO 2 in exhaust gases from heavy industries.

Scientists are closer to finding effective ways to reduce CO 2 levels -- a vital part of responding to climate change and energy efficiency challenges.

A study led by Osamu Ishitani of the Department of Chemistry, Tokyo Tech now demonstrates the advantages of applying electrocatalysis1 to capture low-concentration CO 2 .

In their study published in Chemical Science, Ishitani and colleagues including Hiromu Kumagai and Tetsuya Nishikawa drew on decades of work on honing the capabilities of a rhenium-based catalyst, and demonstrated its ability to reduce low-concentration CO 2 in the presence of a chemical called triethanolamine (TEOA).

Compared to many previous studies that have focused on reducing pure CO 2 , few have explored how to improve direct capture of low-concentration CO 2 -- a topic that warrants further investigation, considering that plants harness low concentrations of CO 2 (about 400 ppm, that is 0.04% of the atmosphere) and exhaust gases from heavy industries typically contain low levels of CO 2 (around 3-13%).

By avoiding the need for additional energy-consuming condensation processes, their strategy, if scaled up, could provide a more viable, environmentally friendly solution to CO 2 capture in many settings.

In a series of experiments to assess electrocatalytic activity, the researchers found that at a CO 2 concentration of 1%, the rhenium-based catalyst showed very high selectivity (94%) towards carbon monoxide (CO) formation.

A likely reason behind the high performance, the researchers say, is the efficient insertion of CO 2 into the rhenium-oxygen bond.