Effect of Lanthanum Incorporation on the Structural, Surface, and Thermal Properties of Nickel-Co-Doped Alumina and Silica Oxides

<jats:p>Rare-earth-promoted transition metal oxides have attracted significant attention owing to their ability to modify structural, textural, and surface characteristics of functional ceramic materials. In the present work, lanthanum and nickel co-doped oxide systems supported on alumina (Al2O3) and silica (SiO2) were synthesized with varying lanthanum concentrations to investigate the influence of rare-earth incorporation on physicochemical properties. Nickel loading was maintained at 20 wt.%, while lanthanum content was systematically varied between 15-30 wt.% depending upon the support composition. A comprehensive characterization study was performed using scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDX), elemental mapping, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric-differential thermal analysis (TG-DTA). Morphological examination revealed substantial modifications in particle architecture and surface texture with increasing lanthanum loading. Elemental mapping and EDX analyses confirmed the successful incorporation and homogeneous distribution of nickel and lanthanum species throughout the oxide matrices. XRD investigations indicated the formation of crystalline oxide phases and revealed notable structural interactions between dopant species and support materials. Textural characterization demonstrated a progressive reduction in specific surface area with increasing lanthanum concentration. For alumina-supported systems, the surface area decreased from 120.87 to 85.87 m2 g-1, while silica-supported materials exhibited a reduction from 74.44 to 60.66 m2 g-1, suggesting partial pore occupation and increased framework densification upon lanthanum incorporation. FTIR and XPS analyses further verified the formation of metal-oxygen bonding environments and changes in surface chemical states induced by co-doping. Thermal investigations revealed distinct decomposition 2 stages associated with precursor transformation and oxide formation, while kinetic analysis demonstrated temperature-dependent enhancement of decomposition rates. Collectively, the results establish that lanthanum functions as an effective structural modifier, significantly influencing morphology, crystallinity, surface chemistry, textural properties, and thermal stability of nickel-doped alumina and silica materials. The findings provide valuable insights into the design and optimization of rare-earth-modified oxide systems for advanced materials applications.</jats:p>