Atomic scale understanding of the role of Ni/XSZ interface in internal reforming SOFC in low CH4/H2O environment

The role of Ni/XSZ interfaces (dopant X; X = Y or Sc) in the performance of CH4 internal reforming SOFC in a low CH4/H2O environment was studied experimentally and via density functional theory (DFT) calculations. The Ni/ ScSZ anode demonstrated higher and more stable power output at S/C ratio of 0.15 as compared with the Ni/YSZ anode. The difference in H2 and CO production rates between Ni/ScSZ and Ni/YSZ was much higher in the discharge mode than in the nondischarge mode. In the discharge mode, the H2 and CO production rates in Ni/ ScSZ were approximately 2.3 and 2.7 times higher than those in Ni/YSZ, respectively. In the DFT calculations, oxygen spillover and the CHO formation reaction (CH + O -> CHO) were the focus. The activation barriers of above in Ni/ScSZ were lower than those in Ni/YSZ, thereby increasing the power output and H2 and CO production rates.