Core-Shell Structured Phenolic Polymer@TiO₂ Nanosphere with Enhanced Visible-Light Photocatalytic Efficiency

Core-shell structured TiO₂ is a promising solution to promote the photocatalytic effectiveness in visible light. Compared to metal or semiconductor materials, polymers are rarely used as the core materials for fabricating core-shell TiO₂ materials. A novel core-shell structured polymer@TiO₂ was developed by using phenolic polymer (PP) colloid nanoparticles as the core material. The PP nanoparticles were synthesized by an enzyme-catalyzed polymerization in water. A subsequent sol-gel and hydrothermal reaction was utilized to cover the TiO₂ shell on the surfaces of PP particles. The thickness of the TiO₂ shell was controlled by the amount of TiO₂ precursor. The covalent connection between PP and TiO₂ was established after the hydrothermal reaction. The core-shell structure allowed the absorption spectra of PP@TiO₂ to extend to the visible-light region. Under visible-light irradiation, the core-shell nanosphere displayed enhanced photocatalytic efficiency for rhodamine B degradation and good recycle stability. The interfacial C-O-Ti bonds and the π-conjugated structures in the PP@TiO₂ nanosphere played a key role in the quick transfer of the excited electrons between PP and TiO₂, which greatly improved the photocatalytic efficiency in visible light.