Study On Preparation And Properties Of Compound Electrode For CO₂ Photoelectric Catalytic Reducting To CH₃OH

Using CO2 to obtain high value-added products,it is called "negative carbon" concept,and the photoelectric catalysis method is one of the most clean,gentle and reasonable conversion methods.But the development and application of the photoelectric catalysis methods is often limited by catalyst materials’ defects.In this paper,Ti O2 and Cu2 O were selected as the main components of the catalyst,and the corresponding composite photoelectric anode and photo-electric cathode were prepared respectively,and the CO2 was reduced to high added value liquid fuel—methanol by using the standard three-electrode system.The con-ditions of the composite process are optimized and determined,and the phase,structure and properties of the prepared composite photo-electric poles are characterized and tested.The properties of reducing CO2 to prepare methanol by self-made photoelectric catalytic system were further analyzed.The main results are as follows:(1)Graphene(GR)and graphdiyne(GD)were selected as carriers of Ti O2,and urea was selected as GR dispersant,and the corresponding Ti O2-GR(Urea)and Ti O2-GD composite electrodes were prepared.When the addition of GR is 2 g/L,the content of urea is 2.5 mol/L,GD is 1 g/L respectively,the performance of Ti O2-GR(Urea)and Ti O2-GD is the best.The current density reached 1.48 m A/cm2 and 1.56 m A/cm2 respectively,3.6 times and 3.8 times respectively as pure Ti O2 catalysts.(2)C-Cu2 O,C-Cu2O-Zn O and C-Cu2O-Fe2O3 composite electrodes were prepared by compounding non-metallic carbon,and modifying zinc oxide(Zn O)nanorod and ferric oxide(Fe2O3)at Cu2 O.When the time of Cu foil soaking in the precursor solution is 30 min,the concentration of the precursor solution in the preparation of the composite Zn O nano-rod is 0.04 mol/L,and the method of Fe2O3 composite is the pull-up method,the optical current density of C-Cu2 O,C-Cu2O-Zn O and C-Cu2OFe2O3 composite electrodes reached-1.52 m A/cm2,-3.03 m A/cm2 and-2.89 m A/cm2 respectively and the optical current(ICO2)generated by the reduction of CO2 reached 0.66 m A/cm2,1.94 m A/cm2 and 1.91 m A/cm2,respectively.The stable using life is the longer than pure Cu2 O electrode reached 500 min and the performance is significantly higher than the pure Cu2 O electrode.(3)When the external bias is-1.1 V(vs.SCE),the catalytic performance of the photoelectric catalysis system composed by self-made photoelectric poles was the best,and the methanol yield after 6 h reaction could reach 195.04 mmol/cm2.