The Structure of CaxLa1–xAlO3 Aluminates and the Role of Surface Oxygen in the Processes of High-Temperature Catalytic Oxidation of C1–C3 Alkanes

The structural features and a series of properties of \({\text{C}}{{{\text{a}}}_{x}}{\text{L}}{{{\text{a}}}_{{1 - x}}}{\text{Al}}{{{\text{O}}}_{3}}\) (x = 0–0.3) aluminates have been studied. The limits of stability of the cubic perovskite \({\text{C}}{{{\text{a}}}_{x}}{\text{L}}{{{\text{a}}}_{{1 - x}}}{\text{Al}}{{{\text{O}}}_{3}}\) structure under the isomorphic substitution La³⁺ → Ca²⁺ have been determined by X-ray diffraction analysis. The dependence of the state of oxygen on the surface of the obtained samples on their composition has been studied by X-ray photoelectron spectroscopy (XPS). Based on a comparison of the XPS data with the catalytic properties of \({\text{C}}{{{\text{a}}}_{x}}{\text{L}}{{{\text{a}}}_{{1 - x}}}{\text{Al}}{{{\text{O}}}_{3}}\) samples in the oxidation of C₁–C₃ alkanes, it was concluded that point defects (oxygen radical ions O^– and surface OH^– groups) are involved in the activation of reactant molecules, hydrocarbons and oxygen.