(617ev) Electrochemical CO2 Reduction in an Oxygen-Ion Conducting Solid Oxide Electrolyzer Cell (SOEC)
Solid oxide electrolyzer cells (SOECs) used in high temperature CO2 electrolysis are basically solid oxide fuel cells (SOFCs) operated in reverse . In the present study, an oxygen-ion conducting electrolyzer type reactor was used for the electrolysis of carbon dioxide into carbon monoxide and oxygen using external electricity. The SOEC reactor used in this study consists of a button cell, i.e., an electrode-electrolyte assembly, and an alumina tube. Yttria-stabilized zirconia (YSZ) disc which has a thickness of 125 µm, La-doped strontium titanate (LST) type perovskite and (La0.8Sr0.2)0.95MnO3-Î´ (LSM) mixed with YSZ were used as electrolyte, cathode and anode, respectively. The activity and stability of synthesized perovskite was compared with Ni-YSZ type commercially available electrode material. In electrocatalytic CO2 reduction experiments, pure carbon dioxide was flowed to the cathode side and data was collected at a current range of 0-5 mA at 600oC.
The La-doped strontium titanate type perovskite material used in this study was synthesized via modified Pechini method . The characteristics of the synthesized material were investigated using several techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared spectroscopy (DRIFTS), CO2-TPO (temperature-programmed oxidation with CO2), and electronic conductivity measurements.
Temperature-programmed oxidation (TPO) was performed on post-reaction button cells (both on LST and Ni-YSZ cells) in order to compare the coke deposition on cathode during CO2 reduction.
The aim of this study is to show that high-temperature electrocatalytic CO2 reduction in a SOEC type reactor is a promising, energy efficient alternative for syngas production. The results obtained so far indicated that La-doped strontium titanate perovskite materials can be considered as promising cathodes for CO2 electro-reduction and using perovskites as cathode material can significantly enhance the durability of the system by lowering the coke deposition.
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