Enhance coking tolerance of high-performance direct carbon dioxide-methane solid oxide fuel cells with an additional internal reforming catalyst

Abstract

Carbon deposition can be observed on the surface of Ni catalyst surface because of its high catalytic activity of hydrocarbon cracking, and thus cause the degradation of cell performance. In this work, anode supported single cells without and with the additional internal reforming catalyst NiFe 2 O 4 -GDC are successful assembled, and then used to characterize electrochemical performance and carbon tolerance in H 2 and 50%CO 2 –50%CH 4 fuels. Both single cells without and with NiFe 2 O 4 -GDC demonstrate similarly high electrochemical performance and low electrode polarization resistance fueled in H 2 , and the peak power densities are 1037.15 and 1163.36 mW/cm 2 at 800 °C, respectively, the difference of which derived from the ohmic impedance and the electrode polarization resistance. Interestingly, to better understand the contribution of different electrode polarization impedances, the distribution of relaxation time (DRT) analysis is used to distinguish different rate-limiting steps with high resolution. While 50%CO 2 –50%CH 4 fuel is applied, single cells with internal reforming catalyst NiFe 2 O 4 -GDC demonstrates high electrochemical performance (1046.72 mW/cm 2 at 800 °C), long-term stability and excellent carbon tolerance from the Raman scanning analysis. All preliminary experimental results suggest that high performance and coking tolerance can be obtained for direct carbon dioxide-methane solid oxide fuel cells with an additional internal reforming catalyst. • The fuel pre-reforming by CO 2 is an effective method for carbon removal. • High-performance direct carbon dioxide-methane solid oxide fuel cells can be realized. • Additional internal reforming catalyst is used to enhance coking tolerance. • DRT analysis is used to distinguish different rate-limiting steps of electrode process. • Raman spectra analysis is performed to evaluate the carbon deposits of anode catalyst.