(258d) Reverse Water Gas Shift Reaction over Cu-Fe/Al2O3 Catalyst in Solid Oxide Electrolysis Cells
Reverse water gas shift (RWGS) reaction is a practical method to convert CO2 to CO utilizing hydrogen supplied from clean energy sources. Solid oxide electrolysis cells (SOECs) are new energy conversion devices with high efficiency and environmental compatibility. They can split steam (H2O) into hydrogen and oxygen by using electricity generated from clean energy sources (such as solar energy and wind energy). Thus, applying the SOECs in the RWGS reaction could be a feasible way for efficient conversion of CO2 using renewable energy sources. RWGS reaction was carried out over Fe-Cu/Al2O3 catalyst by a fixed-bed quartz tube reactor using externally supplied hydrogen at temperature of 700 oC, while fixing total flow rates of H2 and CO2 at 100 ml/min (CO2:H2 is 1:1). The catalyst showed good catalytic activity with CO2 conversion of 42% which is close to the equilibrium conversion. TEM and XRD analysis results confirmed that the sintering of active sites was prevented during the reaction. Cu-Fe/Al2O3 catalyst was then utilized as a functional reforming layer for the cathode of a conventional SOEC single cell. The single cell consisted of Ni-yttria stabilized zirconia (YSZ) cathode support/YSZ/Ce0.8Sm0.2O1.9 (SDC) bi-layer electrolyte/La0.6Sr0.4Co0.2Fe0.8O3-Î´ anode. Using this SOEC single cell with the catalysts layer, the RWGS reaction was investigated under the applied electric load condition. Our results indicated that by electrolysing H2O over the cathode of SOEC cell, a reduced amount of external hydrogen is needed to obtain a similar CO2 conversion as the fixed-bed quartz tube test.