Electrochemical Conversion of Carbon Dioxide to Formic Acid Using Sn-Zn Alloy Catalysts

H-Y Kim, S.H. Ahn, S.J. Hwang, S.J. Yoo, J. Han, E. Cho, J.H. Jang, S-K Kim
Chung-Ang University, KR

Keywords: carbon dioxide, electrochemical conversion, catalyst

Summary:

In this study, we have developed a new alloy catalyst for high efficiency conversion of CO2 to formic acid. We have fabricated a series of Sn-Zn alloy catalysts using electrodeposition methods. SnSO4 and ZnSO4•7H2O were used as metal precursor and electrodeposition were performed on Cu foil. Pt sputter coated Ti mesh and Ag/AgCl were used as counter electrode and reference electrode, respectively. Figure 1 presents the SEM image of SnZn alloy catalyst fabricated by electrodeposition. Electrochemical reduction of CO2 was performed in the cell with two compartments separated by proton exchange membrane. The catholyte and anolyte were 0.5M KCl and 0.1M KOH and the cell temperature was maintained at 25oC. As shown in figure 2, which is the chronoamperometry result of CO2 reduction according to the catalysts, the SnZn alloy catalyst exhibited the highest reduction current. From the HPLC analysis data, it was found that the faradaic efficiencies of formic acid formation on SnZn catalyst was higher than 90%, while the single metal catalysts had efficiencies of 64 ~ 88%. The results clearly indicate that the fabricated SnZn alloy catalyst will greatly contribute to the development of electrochemical reduction of CO2.