Electrocatalytic Reduction Of CO₂ On Nanocrystalline TiO₂ Electrodes Modified By Pt Or Sn And Structural Characterization Of Electrolytic Fixed Product

With the further development of global economy, environment problems resulted from CO₂ had got much serious considerations. It has become a world focus that how to reduce CO₂ in the air, buffering "greenhouse effect". The electrochemical fixation of CO₂ has the advantages that reactive conditions are mild and it is friendly to environment, which belongs to "green chemistry" methods and recently receives great attentions from chemists.The electrocatalytic reduction of CO₂ on nanocrystalline TiO₂ electrodes modified by Pt or Sn were investigated and the electrolytic fixed product was structurally characterized in this paper, which was composed of three parts:First, preparations and electrochemical tests of Pt or Sn particulates modified nano- TiO₂ electrodes. TiO₂ precursor, Ti(OEt)4, which was directly hydrolyzed, coated, and calcined to produce nano-TiO₂ film electrode, was electro-synthesized using sacrificial metal anode method. Nanocrystalline TiO₂ -Pt(or Sn) modified titanium electrodes were prepared by electro- depositing Pt or Sn particulates on nanocrystalline TiO₂ film. Electrocatalytic activities of Ti/nano-TiO₂ and Ti/nano-TiO₂-Pt(or Sn) electrodes in the reduction of CO₂ were studied by electrochemically transient methods. The results showed that the three electrodes have electrocatalytic activities in the reduction of CO₂ all.Second, the fixation of CO₂ on Ti/nano-TiO₂-Pt(or Sn) electrodes were investigated by controlled-voltage or controlled-current electrolysis in 0.5M KHCO3 solution under room temperature and ambient pressure. Electrolysis fixed product resolved in solution of CO₂ were identified using HPLC method and chemical tests, which revealed that reduced products are polar matter and chemically active.Finally, analysis and characterization of reduced product of CO₂ using HPLC, UV, IR, MS,and 1HNMR methods were carried out. According to analysis by synthesis on the four spectra of product, molecular weight was determined to be 258, and molecular formula C11H14O7. The product is a conjugated multiple-carbonyl compound and it is a new compound, due to not been searched out in CA formula index.