Thermodynamic Analysis of the Efficiency of Photoelectrochemical CO₂ Reduction to Ethanol

Over the last decades, long-term fossil fuel shortage and growing global demand for energy ignited an interest in developing alternative and "green" approaches for fuel production. One promising way to generate solar fuels is photocatalytic or photoelectrochemical (PEC) CO2 reduction. Although various research efforts were undertaken to improve the efficiency and stability of PEC devices, many questions remain that have not been adequately answered due to lack of understanding of the reaction mechanisms and underlying limiting factors. In this study, we illustrate the thermodynamics of single or double-junction photo-absorbing materials. Finally, this research work investigated the efficiency limits of solar-driven CO2 conversion into ethanol as a two-step process with formate as intermediate.