Selective insertion of La oxides into micropores of SBA-15 and preparation of highly ordered mesoporous La–Si oxides with high stability against alkaline hydrolysis

Abstract Lanthanum oxides were selectively inserted into the micropores of SBA-15 via a simple impregnation and subsequent calcination method, forming mesoporous La–Si oxides (SBA-La). Characterization by using powder X-ray diffraction (XRD), N₂ adsorption, and transmission electron microscopy (TEM) confirmed that La oxides preferentially fill the micropores without damaging the mesopore structure. Upon excess loading, La oxides occupy mesopores while retaining cylindrical mesoporous morphology. SBA-La exhibits significantly enhanced stability against alkaline hydrothermal conditions compared with unmodified SBA-15. The improved durability is attributed to the formation of La oxides in micropores, which suppresses degradation pathways. This strategy provides a simple and effective route to improve the chemical robustness of mesoporous silica materials.