Renewable and high efficient syngas production from carbon dioxide and water through solar energy assisted electrolysis in eutectic molten salts

Over-reliance on non-renewable fossil fuel leads to steadily increasing concentration of atmospheric CO₂, which has been implicated as a critical factor contributing to global warming. The efficient conversion of CO₂ into useful product is highly sought after both in academic and industry. Herein, a novel conversion strategy is proposed to one-step transform CO₂/H₂O into syngas (CO/H₂) in molten salt with electrolysis method. All the energy consumption in this system are contributed from sustainable energy sources: concentrated solar light heats molten salt and solar cell supplies electricity for electrolysis. The eutectic Li_0.85Na_0.61K_0.54CO₃/nLiOH molten electrolyte is rationally designed with low melting point (<450 °C). The synthesized syngas contains very desirable content of H₂ and CO, with tuneable molar ratios (H₂/CO) from 0.6 to 7.8, and with an efficient faradaic efficiency of ∼94.5%. The synthesis of syngas from CO₂ with renewable energy at a such low electrolytic temperature not only alleviates heat loss, mitigates system corrosion, and heightens operational safety, but also decreases the generation of methane, thus increases the yield of syngas, which is a remarkable technological breakthrough and this work thus represents a stride in sustainable conversion of CO₂ to value-added product.