Preparation And Photocatalytic CO₂ Reduction Of Binuclear Cobalt Organic Polymer And Its Composite

Fossil fuels such as coal,oil and natural gas account for about 80%of human energy demand.However,fossil fuels are a non-renewable resource with uneven regional distribution,while their combustion leads to excessive emissions of CO₂,SO₂,particulate pollutants,etc.Among them,a large amount of CO₂ emissions have caused a serious greenhouse effect,which is not conducive to sustainable human development.Therefore,there is an urgent need for mankind to address the issue of CO₂ storage and conversion.The photocatalytic conversion of CO₂ into high value-added fuels or fine chemicals is an ideal way to enrich the energy supply and mitigate the greenhouse effect.Due to the excellent thermodynamic and kinetic stability of CO₂,developing inexpensive,stable,and efficient photocatalysts is the key to solving CO₂ conversion.In this thesis,binuclear cobalt organic polymer and Polymer/Ti O₂ composite were designed and synthesized,and their photocatalytic CO₂reduction properties were studied.The specific research contents are as follows:1.Binuclear cobalt organic polymer was designed and synthesized by Sonogashira coupling reaction with binuclear cobalt complex and2,2-Dimethyl-1,3-diaminopropane.The structure and morphology of binuclear cobalt organic polymers were characterized by Raman,IR and HRSEM,and their photocatalytic CO₂ reduction properties were studied.The results of catalytic experiments show that the photocatalytic reduction rate of CO₂ to CO by binuclear cobalt organic polymer is 77.65 mmol g^-1 h^-1,and the selectivity is 92.33%.The isotope labeling experiment confirmed that CO came from photocatalytic CO₂reduction.The fluorescence quenching experiment further clarified that the photocatalytic CO₂ reduction process of binuclear cobalt organic polymers belongs to the reduction quenching path.2.In order to realize the artificial photosynthetic catalytic reaction,the composite artificial photosynthetic catalyst was constructed by compounding binuclear cobalt organic polymer and Ti O₂ semiconductor material.The structure of the composite catalyst was characterized by Raman and XPS,and the photocatalytic CO₂ reduction performance of polymer/Ti O₂ composite was studied.The results of catalytic experiments show that the composite is an excellent photocatalyst,which can oxidize water to O₂ and reduce CO₂ to CO.The rate of CO formation is 131.86μmol g^-1 h^-1,which is three times higher than that of pure Ti O₂.The*COOH and*CO intermediates of photoreduction of CO₂ to CO were detected by In-situ FTIR spectra.The photoelectrochemical experimental results show that,compared with Ti O₂,the composite has larger photocurrent,lower impedance and weaker fluorescence emission intensity,so it shows better charge separation efficiency,which explains the better photocatalytic CO₂ reduction performance of the composite.