Hydrothermally tailored TiO2 nanostructures for selective photocatalytic oxidation of benzyl alcohol and 3-pyridinemethanol: Influence of alkali concentration and aromatic ring chemistry
Surfaces and Interfaces, cilt.98, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 98
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.surfin.2026.110215
- Dergi Adı: Surfaces and Interfaces
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC
- Anahtar Kelimeler: Alkali effect, Aromatic ring chemistry, Hydrothermal synthesis, Photocatalysis, Selective oxidation, TiO2 nanostructures
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
TiO2 nanostructures were synthesized hydrothermally using different NaOH concentrations (1–10 M) at 180 °C, followed by calcination at 300 °C, to tune crystallinity, morphology, and surface properties. Their performance was evaluated in the selective photocatalytic oxidation of benzyl alcohol to benzaldehyde and benzoic acid, and 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 in water under UVA irradiation. The materials were characterized by XRD, SEM, BET, FT-IR, TGA, XPS, DRS, and photoelectrochemical measurements. Structural and surface analyses revealed an alkali-dependent transition: TiO2 prepared with ≤2.5 M NaOH retained high anatase crystallinity, whereas NaOH concentrations ≥5 M induced a dissolution–reorganization process yielding predominantly amorphous and highly porous structures, with 5 M identified as a critical threshold. Photocatalytic results showed that 3-pyridinemethanol exhibited higher oxidation rates and product selectivity than benzyl alcohol, highlighting the beneficial role of the nitrogen-containing aromatic ring in selective benzylic oxidation. Benzyl alcohol showed higher activity on more crystalline TiO2, but lower selectivity due to stronger adsorption of benzaldehyde, promoting overoxidation pathways. In contrast, adsorption experiments demonstrated weaker interaction and faster desorption for 3-pyridinemethanal. Competitive co-substrate, reusability, and long-term stability experiments further confirmed the substrate-dependent surface interactions and structural robustness of the photocatalysts. Scavenger experiments confirmed superoxide radicals (•O2⁻) as the dominant reactive species for both substrates, while Ag⁺ significantly inhibited the reaction only on predominantly amorphous TiO2. Overall, selective oxidation in aqueous media was governed by the interplay between TiO2 crystallinity, interfacial surface properties, and substrate-dependent adsorption/desorption behaviour.