Electrochemical Performance of Infiltrated Cu-GDC and Cu-PDC Cathode for CO_2 Electrolysis in a Solid Oxide Cell

摘要

Solid oxide cells are fabricated by utilizing infiltration technique to impregnate: Cu-gadolinium doped ceria (GDC) and Cu-praseodymium doped ceria (PDC) electrodes in yttria stabilized zirconia (YSZ) scaffold. Electrochemical performance of the cell is measured for CO_2 electrolysis in presence of H_2 gas. The polarization resistances of the cell with Cu-PDC cathode are measured to be of relatively lower value 17.9 Ω cm~2 and 5.1 Ω cm~2 as compared to the corresponding 23.8 Ω cm~2 and 7.5 Ω cm~2 on Cu-GDC electrode for CO_2/H_2 ratio of 92/08 and 28/82 respectively. Similarly, CO_2 electrolysis current on Cu-PDC cathode are measured relatively higher to the values of -0.056 A cm~(-2) at CO_2/H_2 = 76/24, -0.069 A cm~(-2) at CO_2/H_2 = 56/44 and - 0.075 A cm~(-2) at CO_2/H_2 = 38/62. Impedance spectra of Cu-PDC cell at varying potential, indicated a significant decrease in polarization resistance from 17.9 Ω cm~2 to 6.3 Ω cm~2 as the applied potential increased from OCV (-0.89 V) to -1.6 V at CO_2/H_2=92/08. Thus, the experimental results suggested an improved electrocatalytic activity of Cu-PDC cathode as compared to Cu-GDC electrode, which is further improved on increasing the H_2 concentration in the feed.