Photocatalytic Reduction Of CO₂ Based On Nickel Complex And Zinc Porphyrin Complexes

The exploitation of fossil fuels has led to a series of environmental and energy problems.CO₂ as a large carbon energy pool,photocatalytic reduction of CO₂ to energy or chemical materials.According to the research progress in related fields at home and abroad,photocatalytic materials transition from semiconductor phase to metal complexes.Non-noble metal complexes are becoming more and more mature in the field of photocatalysis due to their low cost,easy synthesis,preservation,high efficiency and high selectivity.Three kinds of nickel complex catalysts and three kinds of zinc porphyrin complex photosensitizers ware synthesized using 2,2'-Bipyridine,4,4'-Dimethy-2,2'-dipyridyl,1,2-bis?dicycloethylphosphoryl?-ethaneand5,10,15,20-tetraphenylporphyrin,5,10,15,20-tetra-p-tolylprphyrin,5,10,15,20-tetrakis?4-?trifluoromethyl?phenyl?porphyrin as the ligand.Six complexes ware characterized,spectral analysis,electrochemical analysis and applied for photocatalytic reduction of CO₂.The photocatalysis mechanism diagram of nickel complex was also discussed.The primary contents are as follows:1.They are dinuclear nickel complexes with six coordination sites by crystal data of C₂₀H₂₀Cl₄N₄Ni₂O₂ and C₂₄H₂₈Cl₄N₄Ni₂O₂.Although C₂₀H₂₀Cl₄N₄Ni₂O₂ have been by researchers,the photocatalytic reduction of C₂₀H₂₀Cl₄N₄Ni₂O₂ has been not studied and C₂₄H₂₈Cl₄N₄Ni₂O₂ is a new complex.2.In the experiments of the photocatalytic reduction of CO₂ to CH₄ and CO with nickel complexes,through optimizing to obtain optimum photocatalytic conditions:the concentration of photosensitizer[Ru?bpy?₃]²⁺was 0.45 mM,the volume ratio of MeCN:H₂O:TEOA was 3:2:1,the concentration of catalyst was 0.1 mM,the concentration of BIH was 0.03 M,12 W LED blue light??=465 nm?irradiation for 7 h,TONs of CH₄ reached 9.2,10 and 4.7 respectively,the selectivity was 11%,12%and41%,respectively.3.In the study of the photocatalytic reduction of CO₂,zinc porphyrin complexes as photosensitizer,the optimum photocatalytic conditions was obtained as follows:the iron complex as catalyst,the concentration was 0.1 mM,DMF:TEOA=3:1,the sacrificial agent BIH concentration was 0.089 M,and the concentration of photosensitizer was 1.4mM,the TONs of CO was 424,324 and 138 respectively,the selectivity was 98.1%,97.7%and 97.4%respectively.