Photocatalytic Reduction Of CO₂ Catalyzed By Fe???,Co??? Complexes

Recently,photocatalytic carbon dioxide reduction to CO has gradually been a hot issue on research.Finding a reasonable and effective photocatalytic system is of great significance for improving the efficiency of solar energy conversion and realizing the rational utilize of carbon dioxide.In this dissertation,We use iron???and cobalt???as the starting materials to synthesize iron???and cobalt???complexes with bipyridyl and Salophen ligands.The state of affairs on research situation is as follows:Five kinds of bipyridyl and Salophen iron and cobalt complexes were synthesized and characterized by mass spectrometry,¹H-NMR,X-ray single crystal diffractometry,etc.The composition and structure of the complexes were determined and their properties towards photocatalytic reduction CO₂ was performed.1.Using[Fe?bpy?₃]?ClO₄?₂?C₁?as catalyst,Ru?bpy?₃Cl₂·6H₂O as photosensitizer,TEOA and BIH as sacrificial agent,and DMF as solvent,TON value of up to 80696 for CO₂ reduction to CO wasachievedundervisiblelightirradiation.PhotocatalyticCO₂reductionfor[Fe?dmbpy?₃]?ClO₄?₂?C₂?under optimal conditions,TON_CO=91673.[Co?dmbpy?₃]?NO₃?₂?C₃?as a catalyst,PC as solvent,[Ru?bpy?₃]²⁺as photosensitizer,TEOA as sacrificial agent,the TON of photocatalytic CO₂ reduction to CO was 47.3 under visible-light irradiation.The introduction of the electron donating group?-CH₃?to ligand bpy results in high catalytic activity.The introduction of electron donors increases the density of the electron cloud and enhances the photocatalytic reduction capability.Cobalt catalysts are less effective in photocatalytic CO₂reduction systems.In order to discuss the possible mechanism for photocatalytic CO₂ reduction,C₁ and C₂ as the main research objects.2.Salophen iron complexes as catalysts?C₄?is less effective than bipyridyl complexes C₁and C₂ in photocatalytic reduction of carbon dioxide.Under visible light irradiation photocatalytic system involving Fe and Co complexes with Schiff base derivative ligand,Ru?bpy?₃²⁺as a photosensitizer,CH₃CN/triethanolamine as solvent and electron donor,TON values of CO generation are 336 and 144,respectively.