Electrolysis technology can be applied to split carbon dioxide into oxygen and carbon monoxide, which can then be transformed into liquid fuels. However, available CO-forming catalysts are either not selective enough or too expensive to be industrially viable.

Researchers from École polytechnique fédérale de Lausanne (EPFL), Switzerland, have developed a catalyst based on copper-oxide nanowires modified with tin oxide which could advance efforts to synthetically produce carbon-based fuels from carbon dioxide (CO₂) and water.

In a solar-driven system, the catalyst was able to split CO₂ with an efficiency of 13.4 percent and reach a Faradaic efficiency of up to 90 percent. The catalyst is formed by depositing atomic layers of tin oxide on copper oxide nanowires. Tin oxide suppresses the generation of side-products commonly observed from copper oxide catalysts, leading to the sole production of CO in the electroreduction of CO₂.

The catalyst was integrated into a CO₂ electrolysis system and linked to a triple-junction solar cell (GaInP/GaInAs/Ge) to make a CO₂ photo-electrolyzer. The resulting gases are separated with a bipolar membrane.

A schematic summary of the electrocatalytic system. (Source: Marce Schreier/EPFL)