Bio-synthesis of TiO2 photocatalyst: a reduced step approach using leaf extract

Abstract

This study demonstrated the effectiveness of a green synthesis approach for TiO2, utilizing basil (Ocimum basilicum) leaf extract as a reducing agent. This method eliminated the need for additional precipitating agents and calcination in the preparation process. TiO2 was synthesized through traditional precipitation (TiO2–P) and biosynthesis with Holy Basil extract (TiO2–B), both resulting in anatase-phase TiO2 as the primary phase. FESEM images revealed that TiO2–P particles (200–250 nm) showed significant agglomeration, while TiO2–B particles were smaller. BET analysis indicated a higher specific surface area for TiO2–B (245.51 m2/g) compared to TiO2–P (19.55 m2/g), enhancing its suitability for photocatalytic applications. The band gap energies were determined to be 3.28 eV for TiO2–B and 3.35 eV for TiO2–P, with both exhibiting similar UV light responses. Photocatalytic testing revealed that TiO2–B achieved 90.4% degradation of tetracycline (TC) within 120 min, outperforming TiO2–P, which achieved 73.0% under the same conditions. Kinetic analysis indicated that the reaction rate constant for TiO2–B (0.015 min−1) was twice that of TiO2–P (0.0075 min−1). Hydroxyl radical generation was also confirmed, and TiO2–B showed reusability over three cycles, highlighting its sustainability and effectiveness for environmental use.

Keywords

• Titanium dioxide
• TiO2
• basil leaf extract
• Ocimum basilicum
• tetracycline