The influence of the synthesis method and pretreatment on the structural features of mixed lanthanum–aluminum oxide samples with a fixed atomic ratio of and on their catalytic properties in methane oxidation has been investigated. The use of organic substances (filter paper or starch) as structuring agents during synthesis, treatment in aqueous or aqueous–ammonia fluids combined with high–temperature processing at different stages makes it possible to vary the phase composition, structural characteristics, and morphology of the resulting systems. It is shown that no direct correlations exist between the structural characteristics, morphology, and catalytic properties of La–Al oxides. It is suggested that the efficiency of the systems in methane oxidation is determined exclusively by the type and concentration of point defects–primarily by the state of surface oxygen anions. At the same time, the phase composition and morphology influence the number and type of active sites and their accessibility to reactants.
Vasyutin et al. (Wed,) studied this question.