Sm2O3-doped ceria (SC) ceramics, in which an yttria-stabilized zirconia (YSZ) thin layer of 2 mu m in thickness was inserted, was fabricated by the electrophoretic lamination method followed by sintering. The pH sensing properties of the SC/YSZ/SC composite ceramics were examined: the result indicated an approximate Nernstian response of -65.3 mV/pH and the response time of within 50 s at 353 K. The electrolytic properties of SC/YSZ/SC composites were also studied using solid oxide fuel cells (SOFCs) and oxygen sensors.