Preparation of COF 2 using CO 2 and F 2 in the electrochemical cell with PbSnF 4 as a solid electrolyte

Abstract

Tetragonal PbSnF 4 was prepared by precipitation method with Pb(NO 3) 2 and SnF 2 aqueous solutions. The product was characterized using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XFS), and the other chemical analyses. Tetragonal PbSnF 4 exhibited the highest electric conductivity of 3.2 Sm −1 at 473 K in air as a fluoride ion conductor. We have investigated the possibility of COF 2 formation using CO 2 and F 2 in an electrochemical cell with PbSnF 4 as a solid electrolyte. At same time, we tried to produce an electric power from an electrochemical cell. This CO 2/F 2 electrochemical cell was constructed with a tetragonal PbSnF 4 disk having Au electrodes. The electromotive force was about 0.9 V at room temperature for 0.1 MPa CO 2/(0.01 MPa F 2 + 0.09 MPa Ar). However, the short circuit current density was 0.24 A m −2, which was quite small. This current density was so small that no fluorocarbon compound was detected after 3 h discharge using FT-IR.