<p>Materials with nominal compositions La_2-xSr_xFeO₄, where x = 0.5, 1, and 1.5, were prepared using a sol-gel auto-combustion technique. Structural characterization of the materials was performed using X-ray diffraction, Mössbauer spectroscopy, and X-ray photoelectron spectroscopy. X-ray diffraction confirmed the formation of single- and double-layered Ruddlesden–Popper (R–P) phases and (La, Sr)FeO_3-δ perovskite, along with minor additional phases such as La₂O₃ and SrCO₃. A mixed oxidation state was detected by Mössbauer spectroscopy only in the strontium-rich sample. XPS analysis revealed mixed Fe³⁺ and Fe⁴⁺ oxidation states on the surfaces of all samples, with the Fe⁴⁺ content increasing with Sr concentration. Catalytic activities of the synthesized materials were evaluated in the reaction of complete oxidation of propane and butane as representatives of volatile organic compounds. A correlation between the presence of Fe⁴⁺ in the perovskite-related catalysts and catalytic activity was established.</p>