Durable catalyst boosts efficiency of high-temperature CO₂ conversion

We’ve all heard that carbon dioxide (CO₂) emissions need urgent solutions, but what if we could turn this greenhouse gas into useful chemicals or fuels? Electrochemical CO₂ conversion—the process of transforming carbon dioxide into valuable products—is a promising path toward greener energy and reducing emissions. The catch? Existing methods either don’t last long or consume too much energy, limiting their real-world use.

Low-temperature CO₂ conversion, for instance, typically lasts less than 100 hours and reaches efficiencies below 35%. The process can be more practical at higher temperatures—between 600 and 1,000°C—but current catalysts often wear out quickly or require costly precious metals. The technology needs an efficient, stable, and cost-effective solution that can turn CO₂ into useful products like carbon monoxide, a key ingredient in many industrial processes.

Now, a team led by Professor Xile Hu at EPFL has crafted a new type of catalyst that promises to make this high-temperature conversion more practical and cost-effective. The catalyst could accelerate the transition towards cleaner industries by converting CO₂ into usable chemicals and fuels. The work is published in the journal Nature.

The researchers developed an innovative catalyst made from a cobalt-nickel (Co-Ni) alloy encapsulated within a ceramic material called Sm₂O₃-doped CeO₂ (SDC). The encapsulation prevents the metal from agglomerating (clumping together), a common problem that reduces catalyst effectiveness.

Impressively, their catalyst operates at 90% energy efficiency, 100% product selectivity, and sustains its performance over an unprecedented 2,000 hours, far surpassing existing technologies.

To create the catalyst, first-author and EPFL postdoc Wenchao Ma used a sol-gel method, a process that mixes metal salts with organic molecules to form tiny metal clusters encased by ceramic shells.

They tested different combinations of metals, discovering that a balanced mix of cobalt and nickel delivered the best performance. Unlike traditional catalysts, which quickly degrade under intense heat, the encapsulated alloy remained stable, maintaining its efficiency even after thousands of hours of continuous operation.

The results were remarkable. The new catalyst maintained an energy efficiency of 90% at 800°C while converting CO₂ into carbon monoxide—a valuable chemical used in industrial processes—with 100% selectivity. In simpler terms, nearly all the electricity used in the reaction directly contributed to producing the desired chemical, without wasteful side reactions.

The breakthrough brings us closer to practical, cost-effective carbon recycling. Instead of releasing CO₂ into the atmosphere, industries could reuse it, transforming waste gas into valuable products. This technology could help industries reduce their environmental footprint, saving both energy and money in the process.

The EPFL team’s catalyst remained stable at industrially relevant conditions for more than 2,000 hours, a milestone that dramatically reduces operating costs. Compared to existing technologies, their approach could cut overall costs by 60% to 80%, according to the researchers’ preliminary estimate.

The catalyst is a significant step towards cleaner industries. By turning CO₂ into valuable products efficiently, we can envision a future where industries recycle carbon emissions as routinely as we recycle paper and plastic today. The EPFL team has filed an international patent application for the catalyst.