High performance of direct ethanol-fueled protonic ceramic fuel cells via ethanol steam reforming using non-noble metal catalysts

Abstract

To prevent anode degradation due to coke from the ethanol fuel in protonic ceramic fuel cells, a reforming layer containing CeO2 and non-noble metal catalysts such as Cu, Ni, and Co is attached to the anode. Ethanol fuel with steam is supplied directly to the anode side. The fuel cell performance with ethanol fuel and the long-term stability of the cell are measured at a low temperature of 500 °C. Coking in the reforming layer and anode of the protonic ceramic fuel cells are also investigated. The reforming layer with Cu/CeO2 is ineffective for preventing coke generation in the Ni-cermet anode because of the poor catalytic activity of the Cu catalyst for ethanol reformation. This results in extensive degradation of the fuel cell performance over time. In the reforming layer containing Ni/CeO2 or Co/CeO2, coke is generated near the surface of the layer, but is absent below the middle. Therefore, placing a reforming layer with a Co/CeO2 or Ni/CeO2 catalyst on top of the Ni-cermet anode prevents coke generation. The Co catalyst exhibits more stable performance over time in ethanol fuel than the Ni catalyst because of the higher catalytic activity of the former for ethanol reformation.