Electrochemical Decomposition of CO 2 in a Fluoride Melt

The conversion of CO2 into carbon materials and oxygen gas has great significance for reducing the greenhouse gas concentrations of Earth and realizing in situ utilization of Mars’ atmosphere. In this work, LiF-Li2O melts containing CO2 were electrolyzed using a Ni cathode and Pt anode at 850°C. Carbon materials with different morphologies were deposited on the cathode and oxygen evolution was detected in anode gas. The products were characterized by Raman spectroscopy, x-ray diffraction, scanning electron microscopy and gas chromatography. The results demonstrated that CO2 was firstly captured and converted into the carbonate in LiF-Li2O melts, and subsequently electrolyzed. The morphologies of the carbon material obtained on the cathode were dependent on the electrolysis potentials. The rate of CO2 and O2 production in the anode gas was related to the reaction process, current density, and potentials. Electrochemical decomposition of CO2 into carbon materials and oxygen gas in a fluoride melt was proved to be feasible.