Abstract
To study the reaction kinetics at the anode of solid‐oxide fuel cells, a nickel stripe pattern was prepared on the surface of yttria‐stabilized zirconia (YSZ) [8 mole percent (m/o) 
] by an ionized cluster beam (ICB) method and photolithography. Due to grain growth of nickel film at high temperatures, the minimum possible width of the stripes was found to be ca. 5 μm. By impedance measurements in 
atmospheres at 700 to 850°C, it was shown that the reaction proceeds through the triple‐phase boundary (TPB) of 
and the mechanism of the rate‐determining reaction is different from that at the TPB of 
. The former takes place on the nickel surface close to the TPB, while the latter just across the TPB. The reaction rate for a unit length of the TPB of 
was slower than that of
by about one order of magnitude.