H3O+-β"-aluminas were synthesized by a hydrothermal process in an autoclave, using K+-β"-aluminas and acetic acid (10 wt. %) as a precursor and an ion exchange medium, respectively. The potassium concentration of the precursor was varied within the molar ratio range, [K2O] : [Al2O3] = 1 : 4~1 : 8, and the acetic acid contents were chosen at the ratios of [K2O] : [CH3COOH] = 1 : 10, 1 : 50, and 1 : 100. The exchange reaction was carried out at 150, 170, and 200 for 2, 4, 6, 8, and 24 h. By repeating a 2 hour reaction twice, the first reaction followed by washing, the highest rate was able to be observed at above 90%. The phase stability and transformation was confirmed by XRD and an IR spectrum, and the ion exchange (rate) was analyzed by ICP and TGA.

Keywords: proton-β"-aluminas, low temperature SOFC, ion exchange reaction.