Influence of visible-light irradiation on physicochemical and photocatalytic properties of nitrogen-doped three-dimensional (3D) titanium dioxide

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• 作者：Hyun Uk Lee ; Soon Chang Lee ; Saehae Choi ; Byoungchul Son ; Hyeran Kim ; Sang Moon Lee ; Hae Jin Kim ; Jouhahn Lee
• 关键词：Titanium dioxide ; Photocatalyst ; Nanostructure ; Photocatalytic activity
• 刊名：Journal of Hazardous Materials
• 出版年：2013
• 出版时间：15 August, 2013
• 年：2013
• 卷：258-259
• 期：Complete
• 页码：10-18
• 全文大小：3373 K

文摘

We report highly active visible-light driven nitrogen-doped three-dimensional polycrystalline anatase TiO₂ photocatalysts (N-3D TiO₂) for environmental and biomedical applications. N-3D TiO₂ is synthesized at a low temperature (<90 ¡ãC) without thermal treatment via a modified hydrothermal process (HP) and ultrasound irradiation (UI). The N-3D TiO₂ is additionally irradiated with visible-light to improve the hydroxylation of its surface. Under visible-light irradiation, the photocatalytic activity of visible-light irradiated N-3D TiO₂ (*N-3D TiO₂; [k] = 1.435 h^?1) is 26.1 times higher than that of 3D TiO₂ ([k] = 0.055 h^?1). The *N-3D TiO₂ is highly recyclable and retained 91.8 % of the initial decolorization rate after fifteen cycles. Interestingly, the *N-3D TiO₂ shows very strong antibacterial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) after exposure to visible-light for 3 h. The antibacterial properties of *N-3D TiO₂ are more effective than those of TiO₂, 3D TiO₂, and N-3D TiO₂. More than 91.3 % of the E. coli is sterilized after ten cycles. There are a large increase in the photocatalytic and antibacterial activity of *N-3D TiO₂ relative to that of N-3D TiO₂ owing to the hydroxylation of the N-3D TiO₂ surface as a result of the visible-light irradiation. These results indicate that *N-3D TiO₂ might have utility in several promising applications such as highly efficient water/air treatment, inactivation of pathogenic microorganisms, and solar-energy conversion.