Preparation Of Transition Metal Complexes And Their Properties For Photocatalytic Oxidation Of HMF And Reduction Of CO₂

The excessive use of coal,oil,natural gas and other fossil energy makes the atmospheric carbon dioxide concentration increase year by year,causing global warming,glacier melting and other problems.In order to effectively alleviate the current situation of energy shortage,we continue to explore new renewable energy instead of fossil fuels.In this paper,we use solar energy to drive the conversion of more useful chemicals and biofuels from low-cost and abundant biomass.On the other hand,we are also committed to effectively reducing carbon dioxide concentration through photocatalytic carbon dioxide reduction,so as to utilize carbon dioxide,a huge "carbon energy pool",which not only saves resources but also protects the environment.In this thesis,based on the development of cheap metal catalysts,different metal phthalocyanine-carbon nitrides composite materials and mononuclear iron phthalocyanine with different substituents were prepared,and their catalytic properties for the photocatalytic oxidation of 5-hydroxymethylfurfural and photocatalytic reduction of carbon dioxide were studied respectively.The specific contents and results are as follows:1.The phthalocyanine complexes of different metals are calcined together with carbon nitride(CN)at high temperature to form four kinds of composite materials of different metals,namely NiPc-CN,Co Pc-CN,Cu Pc-CN and Fe Pc-CN.The catalytic activity of 5-hydroxymethylfurfural(HMF)oxidation to 2,5-dimethoacylfuran(DFF)by optical drive of NiPc-CN composite is the best.Further,NiPc-CN composite material was used as the main catalyst to study the photocatalytic oxidation of 5-hydroxymethylfurfural with the change of each component in the catalytic system.Finally,an optimal condition was selected.At this time,the DFF content of the product reached 0.6692 μmol and the selectivity reached 92.35%.At the same time,a series of characterization methods were used to study the light absorption properties and morphology of the composites.2.Two iron phthalocyanine complexes,tetracarboxylic iron phthalocyanine(Fe Pc)and octa-hydroxyl iron phthalocyanine(8OH-Fe Pc),were synthesized by anhydrideurea method.The structure was characterized by mass spectrometry and infrared,and the phthalocyanine complexes with Q band and B band characteristic absorption peaks were confirmed by UV-visible absorption.The catalytic effects of two phthalocyanine complexes on photocatalytic reduction of carbon dioxide were studied.The photocatalytic carbon dioxide reduction effect was studied from different solvents,different solvent ratios,different photosensitive dosages,different BIH dosages and different catalytic dosages.Finally,the optimal reaction conditions corresponding to each catalyst were determined respectively.When Fe Pc complex was irradiated in LED blue light for 12 h,the catalytic effect was the best.The amount of CO produced was243.27 μmol and the selectivity was 82.54%.When the 8OH-Fe Pc complex was irradiated in LED blue light for 12 h,the catalytic effect was the best.The amount of CO produced was 181.25 μmol and the selectivity was 94.41%.