Depth Analysis of Fe₂O₃-Incorporated Cobalt Synthesized via Gelatin-Modified Silica as Hard Template for Methylene Blue Photodegradation

The escalating occurrence of methylene blue (MB) contamination from textile wastewater underscores the urgent demand for effective photocatalytic remediation. This study presents a depth analysis of Fe2O3-incorporated cobalt photocatalysts synthesized using a gelatin-modified silica hard-template method, followed by calcination at 300 and 550 °C. Structural characterization via XRD, FTIR, and EDX confirmed enhanced crystallinity and Co–O phase formation at elevated temperatures, while BET analysis revealed a reduction in surface area (123.4 to 104.5 m2/g) and pore volume (0.2236 to 0.1875 cm3/g) due to sintering and template removal. FTIR data indicated the attenuation of hydroxyl and water-related bands, suggesting decreased surface hydration at higher temperatures. Despite the decline in surface metrics, α-Fe2O3–Co–550 exhibited superior photocatalytic efficiency, achieving greater than 90% MB degradation under visible light, attributed to an increased cobalt content (Fe:Co≈2:1), improved phase purity, and an optimized electronic structure. Kinetic modeling revealed pseudo-first-order behavior for both samples, with α-Fe2O3-Co-300 showing a higher rate constant (K1 = 0.01116 min−1) yet lower overall degradation performance than α-Fe2O3-Co-550, highlighting the critical interplay of structural order, charge transfer efficiency, and compositional tuning enabled by hard-template synthesis for effective photocatalytic wastewater treatment.