Chemical Precipitation of BaCeO3 – CeO2 Based Nano-ceramic Composite Oxide Materials and Their Physical Characterization

In order to reduce the operating temperature of solid oxide fuel cells (SOFCs), novel electrolyte materials based on CeO2 and BaCeO3 are being developed in the scientific realm. In this context, we propose a new methodology for preparing the nano-ceramic composite materials such as BaCe0.9Gd0.9O3-δ – Ce0.9Gd0.9O2-δ (BCGO–CGO) and BaCe0.8Sm0.2O3-δ – Ce0.8Sm0.2O2-δ (BCSO – CSO) as possible electrolytes for SOFC using a simple low temperature chemical precipitation method. The precursor materials used in this preparation were barium nitrate, cerium nitrate and gadolinium nitrate / samarium nitrate (as basic materials), sodium hydroxide (as a precipitator material) and poly vinyl pyrollidone (as surfactant). In a typical experiment, the aqueous solution containing Ba2+, Ce3+ and Gd3+/Sm3+ ions was mixed with the solution of alkali in a magnetic stirrer and then the required percentage of surfactant was added. The formed hydroxides of Ba, Ce and Gd/Sm were washed with water and ethyl alcohol and dried at 50–100oC for 24 hours. The dried powder was then heat treated for 2 h each at 300, 450 and 600oC respectively and then cooled down to room temperature. It was found that the orthorhombic structure could be formed after being calcined at 600oC for 2 h, and the powders were mainly composed of nano-size particles. Characterization by TGA-DTA, XRD, particle size measurements & SEM are presented to evaluate the fundamental physical properties of the proposed nanocomposite materials.