Preparation And Photocatalytic Reduction Of CO₂ Properties Of Cu/Zn-based MOF Derivatives

With the expansion of human activities,the problem of excessive emissions of carbon dioxide(CO2)has become increasingly serious worldwide.Metal-organic frameworks(MOFs)are a class of porous inorganic-organic hybrid crystalline material composed of organic ligands and metal nodes(metal ions or clusters),which has many characteristics such as high specific surface area,uniform and adjustable porous structure and high-density metal sites.The preparation of photocatalytic materials based on MOFs to convert CO2 into other useful chemicals through photocatalytic reduction is one of the green and sustainable ways to solve current environmental problems.Based on the above research background,we prepared MOF-derived Cu/Zn bimetallic oxides for efficient photocatalytic reduction of CO2 to methanol.The main research content is as follows:(1)Using Cu(Ac)2·H2O,Zn(Ac)2·2H2O and benzene-1,3,5-tricarboxylic acid as raw materials,a series of Cu/Zn bimetallic MOF with different Zn contents were synthesized,and then the MOF derivative,Cu/Zn bimetallic oxides,were prepared by calcination at high temperature.Transmission electron microscopy(TEM)and N2 adsorption-desorption characterizations showed that the Cu/Zn bimetallic oxides have porous fish-scale structures with a pore size of-250 nm and a specific surface area of 94.3m2 g-1.X-ray diffraction(XRD)patterns confirmed the crystal structure of CuO and ZnO.The CO2 adsorption curves showed that the CO2 adsorption capacity of Cu/Zn bimetallic oxides is higher than that of respective monometallic oxides.(2)The synthesized Cu/Zn bimetallic oxide materials were used as photocatalysts in the reduction of CO2 to methanol.Due to the synergistic effect of CuO and ZnO,the photoelectron transfer efficiency has been considerably improved,overcoming the delay of photoelectron absorption and the lack of photoelectrons.The highest reaction rate under simulated sunlight was up to 3710 mmol·gcat-1·H-1.