Synthesis of La_1-xSr_xAlO₃ perovskites by reverse strike co-precipitation method and its soot oxidation activity

La_1-xSr_xAlO₃ (x=0 to 0.4) perovskite materials were synthesized by reverse strike co-precipitation method and their soot oxidation activity were evaluated. All the catalysts synthesized were characterized using XRD, BET specific surface area, FESEM and XPS techniques. As analyzed by XRD, La_1-xSr_xAlO₃ perovskite from x=0 to 0.35 showed the formation of the rhombohedral phase, while for La_0.6Sr_0.4AlO₃ sample the secondary phases SrO, La₂O_3, and Al₂O₃ were also noticed. Sr-doped samples exhibited higher BET specific surface area when compared to pure LaAlO₃. FESEM analysis showed that there is a change in morphology upon doping of Sr into LaAlO₃ lattice. The O1s spectra observed from XPS analysis showed that the La_0.75Sr_0.25AlO₃ sample contained higher amounts of adsorbed oxygen. La, Sr, and Al existed in +3, +2 and +3 oxidation states respectively in all the synthesized samples as confirmed by XPS. Soot oxidation activity tests showed that La_0.75Sr_0.25AlO₃ exhibited higher catalytic activity relative to other catalysts due to the enhanced amount of reactive adsorbed oxygen species.