Synthesis and characterization of Gd ³⁺ and Sm ³⁺ ion doped ceria electrolytes through an in-situ sulphated combustion technique

An in-situ sulphated-combustion synthesis is reported to obtain gadolinium [Ce _0.9Gd _0.1O _1.95] and samarium [Ce _0.9Sm _0.1O _1.95] doped ceria electrolytes for solid oxide fuel cells (SOFCs). Nitrate precursors of cerium, gadolinium and samarium reactants were mixed homogenously with a citric acid fuel with an in-situ addition of 10 and 20 mol% ammonium sulphate [(NH4)2SO4]. The mixture was combusted at 500°C and subsequently calcined at 700°C. The influence of the sulphate addition on the morphology of ceria particles has been analyzed. It is seen that the in-situ SO ₄ ²- ions highly favors the nucleation and growth of doped ceria electrolytes on a nanometer scale with an added advantage of improved crystallinity. TEM analysis indicates loosely agglomerated and nearly spherically shaped ceria nano particles with a maximum particle size of 20 nm.