Paper-structured catalyst with a dispersion of ceria-based oxide support for improving the performance of an SOFC fed with simulated biogas

Abstract

Solid oxide fuel cells (SOFCs) can accept a direct feed of biogas for power generation; however, carbon deposition is a major obstacle to their practical application. When a paper-structured catalyst (PSC) with a dispersion of Ni-loaded flowerlike Ce_0.5Zr_0.5O₂ (Ni/CZ(F)) was applied to the anode of an electrolyte-supported cell (ESC), the open-circuit voltage of the cell directly fed simulated biogas was increased from 0.87 to 0.98 V at 750°C. The rates of cell-voltage degradation and coke formation of the ESC with the Ni/CZ(F)-PSC during 100 h of operation were 4.3% kh⁻¹ and 0.43 mg-C g-PSC⁻¹ h⁻¹, respectively, which were lower than those of an ESC with a Ni-loaded PSC without the CZ(F) dispersion (10.4% kh⁻¹ and 8.1 mg-C g-PSC⁻¹ h⁻¹, respectively). This performance improvement is attributed to the unique porous morphology and high oxygen storage capacity of CZ(F), which can contribute to the prevention of Ni agglomeration and the removal of coke from the catalyst surface, respectively. Thus, the Ni/CZ(F)-PSC can function as a practically applicable reforming domain for an internal-reforming biogas-fueled SOFC.