Sandwich-structured photocathode achieves record efficiency in solar CO2-to-ethanol conversion

Czech researchers have developed a photocathode that uses sunlight to convert carbon dioxide into ethanol. The device combines cuprous oxide with MXene materials and a titanium dioxide layer, preventing rapid degradation in water. This design achieves record conversion efficiency, offering a path to sustainable green fuel production.

The photocathode's design directly addresses cuprous oxide's critical weakness: in aqueous environments under light, the material degrades within tens of minutes, losing functionality like rapidly corroding iron. By pairing it with surface-engineered MXene—a two-dimensional conductive material coated with an ultrathin titanium dioxide layer formed through controlled heating—the researchers created a pathway to rapidly drain electric charge from the copper base, preserving its activity over many hours.

The system's selectivity is equally significant: it produces ethanol as the sole liquid product, avoiding the mixed byproduct streams typical of comparable systems, which simplifies downstream purification. The team's next phase involves reinforcing the photocathode's stability and scaling tests to real daylight conditions, moving beyond controlled laboratory settings toward practical deployment.