Turning pollution into clean fuel with stable methane production from carbon dioxide

Carbon dioxide (CO₂) is one of the world’s most abundant pollutants and a key driver of climate change. To mitigate its impact, researchers around the world are exploring ways to capture CO₂ from the atmosphere and transform it into valuable products, such as clean fuels or plastics. While the idea holds great promise, turning it into reality—at least on a large scale—remains a scientific challenge.

A new study led by Smith Engineering researcher Cao Thang Dinh (Chemical Engineering), Canada Research Chair in Sustainable Fuels and Chemicals, paves the way to practical applications of carbon conversion technologies and may reshape how we design future carbon conversion systems. The research addresses one of the main roadblocks in the carbon conversion process: catalyst stability.

In chemical engineering, a catalyst is a substance that accelerates a reaction—ideally, without being consumed in the process. In the case of carbon conversion, catalysts play a critical role by enabling the transformation of CO₂ into useful products such as fuels and building blocks for sustainable materials.

Copper-based materials are the most efficient catalysts for converting CO₂ into methane, the main component of the natural gas used in water and home heaters, and for electricity generation. However, these copper catalysts undergo significant transformation in the process, and keeping the system working for a long period of time remains critically challenging.

Dr. Dinh’s team has developed an innovative method to synthesize and recycle the copper catalyst during the electrochemical reaction within the carbon conversion system. These exciting results were recently published in Nature Energy.

In this approach, what is added to the system is not the copper catalyst per se, but a catalyst precursor (a substance that requires activation to become an active catalyst). Researchers then use electrical signals to dynamically form catalysts in situ during the CO₂ conversion process.

What’s better: when electric signals are turned off, the catalyst goes back to its precursor form. “Repeating this cycle ensures selective and stable performance over extended periods. This is one of the most stable systems for carbon conversion to date,” says Dr. Dinh.

In traditional carbon conversion systems, once the CO₂ reduction reaction gets started, it needs to keep running to avoid catalyst degradation. But in the new system, when the reaction stops, the catalyst turns back into its precursor form. Once the system is turned back on, in a matter of seconds, it produces a new catalyst and restarts the carbon reduction reaction.

Stability during intermittent operations is crucial for integrating carbon conversion systems and intermittent renewable energy sources, like solar or wind power. Dr. Dinh and the team are energized about the new possibilities these findings present, especially for the production of methane.

“Methane has a remarkably high energy density, which is important for energy storage applications,” says Guorui Gao, a Ph.D. student working on the project. “The seamless compatibility with existing gas infrastructure, including transportation pipelines and storage facilities, makes it suited for large-scale and long-term energy solutions.”

The research involves collaboration from multiple institutions from Canada, the United States, Brazil, Spain and Australia. As a next step, Dr. Dinh’s lab will attempt to apply this same process to produce ethylene, ethanol, and other products. The team will also work to scale up the technology to prepare it for practical applications, paving the way for a more sustainable future.