Solar-driven liquid multi-carbon fuel production using a standalone perovskite–BiVO4 artificial leaf

The synthesis of high-energy-density liquid fuels from CO2 and H2O powered by sunlight has the potential to create a circular economy. Despite the progress in producing simple gaseous products, the construction of unassisted photoelectrochemical devices for liquid multi-carbon production remains a major challenge. Here we assembled artificial leaf devices by integrating an oxide-derived Cu94Pd6 electrocatalyst with perovskite–BiVO4 tandem light absorbers that couple CO2 reduction with water oxidation. The wired Cu94Pd6|perovskite–BiVO4 tandem device provides a Faradaic efficiency of ~7.5% for multi-carbon alcohols (~1:1 ethanol and n-propanol), whereas the wireless standalone device produces ~1 µmol cm−2 alcohols after 20 h unassisted operation under air mass 1.5 G irradiation with a rate of ~40 µmol h−1 gCu94Pd6−1. This study demonstrates the direct production of multi-carbon liquid fuels from CO2 over an artificial leaf and, therefore, brings us a step closer to using sunlight to generate value-added complex products. Photoelectrochemical CO2 reduction to multi-carbon alcohols in standalone devices driven only by sunlight is challenging. Now Rahaman et al. integrate a copper–palladium catalyst in a perovskite–BiVO4 tandem device for solar-driven multi-carbon alcohol production.