A Microfluidic Artificial Photosynthesis Cell for CO₂ Reduction on TiO₂-CuO Photoelectrodes

Utilization of solar energy for photo-electrosynthesis of liquid fuels from water and CO2 is a very promising pathway to reduce anthropogenic CO2 emissions and tackle energy shortage problems. Over the last decades, great efforts have been done to develop efficient semiconducting photocatalysts that promote photoelectrochemical (PEC) CO2 reduction. On the other hand, reactor design of PEC cells has not gained much attention even though it can significantly affect the efficiency of such devices. In this study, TiO2-CuO were deposited on fluorine-doped tin oxide (FTO) substrates and were used as photoelectrodes in a continuous flow PEC microfluidic device under simulated solar light illumination (AM 1.5G) in the presence of CO2-saturated aqueous NaHCO3 electrolyte solution. The optimal photoelectrode exhibited a photocurrent density of 0.82 mA/cm2 at 0.3 V vs RHE while a solar-to-fuel (STF) efficiency of 0.13% was observed in microfluidic PEC cell. Figure 1