600 nm Irradiation-Induced Efficient Photocatalytic CO2 Reduction by Ultrathin Layered Double Hydroxide Nanosheets

Currently, developing effective photocatalysts for reducing CO2 to commercial chemicals and fuels has aroused great interest. However, rates of photocatalytic CO2 reduction remain too low to arouse interest. Herein, we successfully synthesized four different ultrathin MAl-layered double hydroxide (u-MAl-LDH) photocatalysts (where M = Mg2+, Co2+, Ni2+, and Zn2+), each possessing a different number of d electrons in eg orbitals, to explore the influence of the electrons in eg orbitals on CO2 reduction under visible light. The u-CoAl-LDH exhibited the best catalytic activity with [Ru­(bpy)3]­Cl2·6H2O as the photosensitizer, and a very high CO2 to CO conversion rate of 43.73 mmol g–1 h–1 can be found under 600 nm irradiation. Results suggest that manipulating the d-electron configuration in ultrathin LDH photocatalysts through judicious M2+ cation selection is an excellent strategy for tuning the photocatalytic performance for CO2 conversion.