PROCESS FOR SYNTHESIS OF MESOSTRUCTURED OXIDES WITH ELECTROCATALYTIC PROPERTIES FOR ELECTRODES OF SOFC

摘要

The invention relates to binary and ternary mesostructured oxides employed in manufacturing the electrodes of the SOFC-type fuel cells with solid electrolyte and to a process for the synthesis thereof. According to the invention, the oxides exhibit solid nanoparticles of sizes ranging between 6...10 nm, they have a crystalline structure, spheric morphology and high dimensional uniformity, the solids have a poorly ordered porous structure made of mesopores, where the pores have a narrow distribution and an average diameter ranging between 2...8 nm and the specific surface ranges between 100...150 m/g. The process claimed by the invention consists in organizing the phases by dispersing the surface-active agents in the bidistilled water, admixing the metal precursors so that the metal : surface-active agent ratio varies between 2...4, homogenizing and initiating a hydrolysis process by admixture of urea, where the surface-active agent : urea ratio is maintained at the value of 0.05, after the admixture of urea the working temperature being increased to 40...80°C and maintained at this level for 4...8 h, the gelling process being initiated by adjusting the pH value at 9 or 10, using 25% aqueous solution of tetramethyl ammonium hydroxide and, after an ageing interval of 6...24 h at the ambient temperature, the hydrothermal treatment is performed at temperatures ranging between 80...120°C for 1...4 days, the resulting precipitate being filtered and washed with distilled water, dried for 12 hours at 100°C and calcined at 550°C for 8 hours in a nitrogen flow followed by an air flow.