In situ measurements of the redox activity of Ce based anode materials for solid oxide fuel cell applications

摘要

Solid oxide fuel cells (SOFCs) are an efficient, combustion-less, pollution-free power source, and are promising for both stationary and mobile applications (auxiliary power sources). Currently the cermet consisting of yttria stabilized zirconia (YSZ) and Ni is used as anode material but the cost of high temperature materials and the degradation associated with high operating temperature (>1000 C) are two major roadblocks for their widespread applications. Both the cost and materials problems may be reduced by using ceria doped with Pr (PDC) and/or Gd (GDC) and Ni cermets. We have employed in situ electron energy-loss spectroscopy (EELS) to measure the nanoscale redox activity of PDC, Ni loaded PDC and Ni-GDC cermet using an environmental electron scanning transmission electron microscope (ESTEM). HREM images and EELS data were collected in the temperature range of 500 C to 800 C in 130 Pa of hydrogen atmosphere. The experimental results and theoretical models were used to elucidate the effect of compositional heterogeneity, particle size and Ni catalyst on nanoscale redox properties of PDC and GDC.