Synthesis and characterization of Fe₂O₃-TiO₂ magnetic materials: Effect of heat-treatment on catalytic activity of naphthalene hydrogenation

We report physicochemical characterization and catalytic evaluation of Fe₂O₃-TiO₂ magnetic materials synthesized at mild conditions, using co-precipitation method with heat-treatment at 673 K, 773 K and 873 K. Results indicate different crystallographic phases including anatase, hematite, rutile and maghemite with a granular morphology, with no uniform grain-size distribution, as confirmed Rietveld Refinement and SEM techniques. High-Resolution Transmission Electron Microscopy (HR-TEM) confirmed presence of stick, spherical and hexagonal nanoparticles. The N₂-physisorption and Vibrating Sample Magnetometry (VSM) indicated that Specific Area (S_BET) and magnetic remanence response is attributed to calcination temperatures. Diffuse reflectance ultra-violet visible (DR-UV-Vis) and Temperature Programmed Reduction of hydrogen (H₂-TPR) showed photoactive species are related to Fe-based content near its surface, with a superficial metallic iron, during hydrogenation process. A different interaction between iron-oxide and titanium oxide materials is linked to lower magnetic remanence, and this could promote catalytic activation with conversion rates near 80% for 1 h of chemical reaction related to 2⁺ and 3⁺ oxidation states for Fe and Ti species.