The use of a precursor-based synthetic method, namely, the freeze-drying of acetic acid solutions, allows the preparation of single-phased perovskites in the series La1-xKxMnO3+delta (x less than or equal to 0.15) at temperatures as low as 873 K, This soft treatment of the precursors yields products with high specific surface areas (20-26 m(2) g(-1)), constituted by uniform nanometric particles (30-50 nm), with their surface enriched in K and Mn. Samples prepared at 1073 K present lower specific surface areas (7-14 m(2) g(-1)). and show no K- and Mn-enrichment for x less than or equal to 0.15. However, in samples with x=0.20 and 0.25, the presence of a secondary phase, K2Mn4O8, is detected by X-ray diffraction, as well as a surface enrichment in K and Mn. These perovskite materials were found to be active for the catalytic combustion of ethane at low temperatures (573-648 K). As a general trend, the substitution of lanthanum by potassium decreases the areal rate, and for the more substituted samples (x>0.10), it increases the selectivity to ethene.