Photocatalytic syngas synthesis from CO2 and H2O using ultrafine CeO2-decorated layered double hydroxide nanosheets under visible-light up to 600 nm

The rational design of photocatalyst that can effectively reduce CO₂ under visible light (l>400 nm), and simultaneously precise control of the products syngas (CO/H₂) ratio is highly desirable for the Fischer-Tropsch reaction. In this work, we synthesized a series of CeO₂-decorated layered double hydroxides (LDHs, Ce-x) samples for photocatalytic CO₂ reduction. It was found that the selectivity and productivity of CO and H₂ from photoreduction of CO₂ in conjunction with Ru-complex as photosensitizer performed an obvious “volcano-like” trend, with the highest point at Ce-0.15 and the CO/H₂ ratio can be widely tunable from 1/7.7 to 1/1.3. Furthermore, compared with LDH, Ce-0.15 also drove photocatalytic CO₂ to syngas under 600 nm irradiation. It implied that an optimum amount of CeO₂ modifying LDH promoted the photoreduction of CO₂ to syngas. This report gives the way to fully utilize the rare earth elements and provides a promising route to enhance the photo-response ability and charge injection efficiency of LDH-based photocatalysts in the synthesis of syngas with a tunable ratio under visible light irradiation.