Researchers have developed an electrochemical reactor that can lower energy consumption for direct air capture and the removal of carbon dioxide directly from the atmosphere.

Developed by Rice University researchers, the new reactor design could be a part of the solution to the increasing problem of emission impacts on the climate.

The device can enable more agile and scalable carbon dioxide mitigation strategies.

Researchers claimed that conventional carbon capture technologies typically consume substantial amounts of heat and involve multiple steps for regeneration.

They demonstrated one-step electrochemical regeneration of CO2 and alkaline absorbent from carbon-containing solutions in a modular porous solid electrolyte (PSE) reactor.

Specialized reactor

Published in Nature Energy, the study demonstrates specialized reactor as having a modular, three-chambered structure with a carefully engineered porous solid electrolyte layer at its core.

The development is claimed to be big milestone in carbon capture from the atmosphere.

“Our research findings present an opportunity to make carbon capture more cost-effective and practically viable across a wide range of industries,” said Wang, the corresponding author of the study and associate professor of chemical and biomolecular engineering.

Haotian Wang, a Rice chemical and biomolecular engineer and corresponding author of the study, stressed that research findings present an opportunity to make carbon capture more cost-effective and practically viable across a wide range of industries.

Device achieved industry-relevant rates of carbon dioxide regeneration

Researchers maintained that the device has achieved industrially relevant rates of carbon dioxide regeneration from carbon-containing solutions. Its performance metrics, including its long-term stability and adaptability to different cathode and anode reactions, showcase its potential for wide-scale industrial use.

Rsearchers from RICE claim that the new technology offers an alternative to the use of high temperatures in direct air capture processes, which often involve running a mixed gas stream through high-pH liquids in order to filter out carbon dioxide, an acidic gas.

This first step of the process ties up the carbon and oxygen atoms in the gas molecules to other compounds in the liquid, forming new bonds of varying degrees of strength depending on the type of chemical used to trap the carbon dioxide, according to a press release.

“By performing hydrogen evolution and oxidation redox reactions, our PSE reactor selectively split NaHCO3/Na2CO3 solutions, which typically come from air contactors after CO2 absorption, into NaOH absorbent in the catholyte and high-purity CO2 gas in the PSE layer. No chemicals were consumed and no by-products were generated,” mentioned researchers in the study.

New types of chemicals used to trap the carbon dioxide

Researchers claimed that the new types of chemicals used to trap the carbon dioxide have different drawbacks and advantages. Amine-based sorbents are the most widely used, in part because they tend to form weaker bonds which means less energy is required to take the carbon dioxide back out of the solution.

However, they are highly toxic and unstable. Even though basic water-based solutions using sorbents like sodium hydroxide and potassium hydroxide are a greener alternative, they require much higher temperatures to release the carbon dioxide back out, added the press release.