Synthesis And Photocatalytic CO₂ Reduction Of Ultrathin Metal-organic Layers

The massive consumption and non-renewability of fossil fuels have caused serious environmental pollution and energy shortage.Using photocatalytic technology to convert CO₂ in the atmosphere into high value-added chemicals will be an effective way to solve environmental pollution and energy crisis.Metal-organic frameworks（MOFs）have been widely used in catalysis due to their large specific surface areas,highly ordered pore structures,and tunable structures and functions.However,the bulky MOF particles are not conducive to the adequate exposure of active sites,and the bulky size also greatly limits the charge transfer and mass transfer in the catalytic process.If the bulk MOF materials are nanosized into ultrathin metal-organic layer（MOL）nanosheets,the above problems can be solved,and their catalytic performance will be greatly improved.In this paper,we successfully generated ultrathin MOL nanosheets on GO templates using the GO template method,and their photocatalytic CO₂ reduction performance was greatly improved compared with bulk MOFs.The specific research contents of this paper are as follows:1.GO was used as a template to successfully transform massive MOF into ultra-thin MOL nanosheets.By controlling the amount of CoCl₂·6H₂O,a series of ultrathin Co-MOL@r-GO composites（Co-MOL@r-GO-1,Co-MOL@r-GO-2,Co-MOL@r-GO-3）were synthesized.Studies have shown that the addition of CoCl₂·6H₂O will greatly affect the loading and size of Co-MOL,which in turn affects its catalytic performance.By performing the photocatalytic CO₂ reduction of these composites,it was found that their catalytic efficiency was much higher than that of bulk Co-MOF,and the composite Co-MOL@r-GO-2 showed the highest performance catalytic activity.When illuminated for 8 h,the CO yield can be as high as 25442μmol/g_Co-MOL,and the catalytic activity is 21.7 times higher than that of bulk Co-MOF.Studies have shown that,compared with bulk MOFs,the ultrathin nature of MOLs exposes more active sites and is also more favorable for charge transfer and mass transfer.R-GO acts as an electron transport medium between photosensitizers and catalysts,greatly accelerating the transport of photogenerated electrons.Therefore,the photocatalytic CO₂ reduction activity of the Co-MOL@r-GO composite was greatly improved.This indicates that the GO template method is an effective strategy for the synthesis of efficient MOL@r-GO photocatalysts.It also provides a new idea for the synthesis of ultrathin MOL nanosheets.2.A series of ultrathin metal-mixed MOL:Ni Co-MOL@r-GO composites were designed and synthesized using the GO template method for efficient photocatalytic CO₂ reduction,which expanded the GO template method in the synthesis of MOL@r-GO composites.The application of catalytic materials confirms the universality of the GO template method in the synthesis of ultrathin MOL nanosheet materials.