Functional ceramic support as an independent catalyst layer for direct liquid fuel solid oxide fuel cells

Abstract

A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells (SOFCs) running on liquid hydrocarbon fuel. The layer consists of a highly porous Ce0.9Ca0.1O2−δ ceramic backbone and active NiMo catalysts, which could be integrated into the conventional Ni metal containing the anode for internal reforming of the hydrocarbon fuel. Compared to conventional catalyst layers sintered on the anodes, this independent catalyst layer could be simply assembled on top of the anode without additional sintering, thereby avoiding the mismatch of the thermal expansion coefficient between the catalyst layer and the anode and improving stability of a single cell. Moreover, a current collector layer could be inserted between the catalyst and the anode to enhance current collection efficiency and electrochemical performance of the single cell. At 750 ℃, the independent catalyst layer displays high activity towards the catalytic decomposition of methanol, and the single cell could achieve the maximum power density of 400–500 mW·cm−2 in dry methanol. Furthermore, by employing the independent catalyst layer, the single cell offers additional in-situ catalyst regeneration capability under the methanol operation mode. Feeding 10 mL·min−1 air into an anode channel for 5 min is found to be effective to burn out carbon species in the catalyst layer, which reduces the degradation rate of the cell voltage by orders of magnitude from 2.6 to 0.024 mV·h−1 during the operation of 360 h in dry methanol. The results demonstrate the significance of the independent catalyst layer design for direct internal reforming methanol fuel cells.

Keywords

• independent catalyst layer
• nimo–ce0.9ca0.1o2−δ catalyst
• internal reforming
• methanol
• solid oxide fuel cell (sofc)