Preparation of High Surface Area Ni-SDC Cermets Using a Surfactant-Assisted Co-Precipitation Method
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0942-W11-31
Preparation of High Surface Area Ni-SDC Cermets Using a Surfactant-Assisted CoPrecipitation Method Sang Joon Park1, Tae Wook Eom1, Jae Eun Oh1, Hae Kwang Yang1, and Kyung Hwan Kim2 1
Chemical & Bio Engineering, Kyungwon University, Seongnam, Korea, Republic of
2
Electrical Engineering, Kyungwon University, Seongnam, Korea, Republic of
ABSTRACT A surfactant-assisted co-precipitation method was employed for obtaining high surface area NiSDC with improved structural properties for SOFC applications. In the work, a cationic surfactant, cetyltrimethylammonium bromide(CTAB) was employed with NiCl2, SmCl3 and CeCl3 as precursors and NH4OH as mineralizer. The elimination of surfactants upon calcination gives rise to the formation of high surface area NiO-SDC. When calcined at 600°C, the powders with surface area of 249 m2/g, were obtained and the pore size was 14.45 nm. The powders consist of two phases, the cubic NiO and SDC confirmed with X-ray diffraction identification.
INTRODUCTION Solid Oxide Fuel Cell (SOFC) is one of the most efficient and environmental-friendly technologies available for generating power from hydrogen, natural gas, and other renewable fuels, where SOFC combines a fuel, an oxidant across an electrodes, the anode and the cathode [1]. For anode, the important characters are the high electronic conductivity, the good electrochemical activity, the thermal expansion compatibility with other components of cell and the wide triple phase boundary(TPB) [2]. In particular, TPB is very important because the electro-catalytic reaction occurs at the TPB which is the interface between the catalysts, ionic conductors and the pore for the moving of fuel gases [3,4]. Therefore, it is essential that the cermets have high surface area for obtaining wide TPB. In general, as the materials of the anode, rare-earth-doped ceria is used in the low operating temperature and possessing the high ion conductivity [5] and Ni is employed as catalyst since Ni is relatively cheap. Recently, the suitable anode for direct electrochemical oxidation of methane in a solid oxide fuel cell has been suggested to be Ni-SDC cermets. However, Ni-SDC cermets, are usually manufactured by mechanical mixing method, where separately prepared NiO and SDC powders are subjected to homogenization by mechanical mixing and then sintered to form a NiO-SDC composite ceramic. It is clear that mechanical mixing is simple but apt to result in a non-uniform distribution of Ni in the cermets and hence a poor performance. To obtain wide TPB, Marc Mamak et al. [6] synthesized the high surface area Ni-YSZ, Pt-YSZ and LSM-YSZ using cationic surfactant (CTAB; cetylmethylammonium bromide). The common experiment is that the materials (nickel, yttrium and zirconium) are converted into the glycol and the reagents are mixed with the surfactant. In this paper, the porous NiO-SDC was synthesized by using CTAB and the surface area of NiO-SDC was compared with those for the previous work, the sol-gel [7,8], co-precipitation
[9,10], and the mechanical mix
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