Production of syngas by solid oxide electrolysis: A case study

An investigation of syngas production using solid oxide electrolysis was carried out. A conventional solid oxide cell based on Ni supporting cathode, thin yttria-stabilized zirconia electrolyte, yttria-doped ceria interlayer, and strontium-doped lanthanum cobaltite and ferrite-based perovskite anode (Ni-YSZ/YSZ/YDC/LSFC) was used for the reduction of CO2 and water to syngas. This process was assisted by H2 added to the reactant in various amounts to maintain the Ni sites in a metallic state. This was necessary to favour CO2 reaction and to avoid ohmic constraints that may derive from the occurrence of Ni reoxidation as consequence of the presence of oxidising species like CO2 and water. The outlet gas was analysed by gas chromatography. The presence of CO and CH4 beside CO2 and H2 was detected in the outlet stream. Analysis of outlet gas composition revealed that CO was produced by both electrochemical and catalytic mechanisms. Suitable CO2 conversion was achieved using dry gas.