Abstract: Mesoporous Yb-P-co-doped anatase-TiO₂ nano-sheets were synthesized from TiCl₄ hydrolysis by the hydrothermal method. The effect of Yb-P-co-doping on the surface physicochemical properties and photocatalytic activities of TiO₂ and its mechanism were discussed based on the results of XRD, TEM, BET, XPS, FTIR, DRS and PL analysis. The photocatalytic activities of as-prepared samples towards the degradation of 4-chlorphenol in aqueous solution under simulated sunlight irradiation followed the order of TiO₂ < Yb-TiO₂ < P25 < P-TiO₂ < Yb-P-TiO₂, indicating the synergetic effect by Yb-P-co-doping. The TOC removal rate of 4-chlorphenol solution (20 mg·L^-1) in the suspension of Yb-P-TiO₂ (0.8 g·L^-1) reached 87.6% after simulated sunlight irradiation for 120 min, indicating that 4-chlorphenol could be mineralized efficiently. P-doping played a crucial role on both inhibited transformation of TiO₂ from anatase to rutile and improvement of surface texture properties. Yb³⁺ ions could capture photo-generated electrons to form Yb²⁺, which inturn release electrons to acceptor, such as O₂ adsorbed on the surface to produce ·O₂^-, thus effectively inhibiting recombination of photo-generated charge carriers. The improved light absorption property of Yb-P-TiO₂ was attributed to narrowing band gap owing to the cooperative effect of energy levels hybridized by the 3p orbits of P atoms and the 2p orbits of O atoms and energy levels of oxygen vaccancies. Yb-P-co-doping could further inhibit recombination of photo-generated electrons and holes, enhancing quantum efficiency, and could further increase the surface hydroxyl, which was in favor of the capture of photo-generated holes and formation of strong oxidative hydroxyl free radicals. All above factors were beneficial to enhance photocatalytic activity of Yb-P-TiO₂.

Key words: TiO₂, hydrothermal, hydrolysis, nano-materials, TiCl₄, Yb-P-co-doping

摘要： 利用水热技术以TiCl₄水解法制备介孔锐钛矿Yb-P-TiO₂纳米片.基于XRD、TEM、BET、XPS、FTIR、DRS和PL分析,探讨Yb和P共掺杂对TiO₂表面物理化学特性及光催化活性的影响机制.在模拟太阳光照射下,样品光催化降解4-氯酚活性顺序为:TiO₂ < Yb-TiO₂ < P25 < P-TiO₂ < Yb-P-TiO₂,表明Yb-P共掺杂对提高光催化活性产生协同作用.20 mg·L^-1的4-氯酚溶液在0.8 g·L^-1的Yb-P-TiO₂悬浮液中经模拟太阳光照射120 min后,TOC去除率达87.6%,表明4-氯酚能够被有效矿化.P掺杂对抑制TiO₂由锐钛矿向金红石相的转变和改善表面结构特性起决定性作用.Yb³⁺能俘获光生e^-生成Yb²⁺,Yb²⁺又易于将e^-转移给表面吸附O₂生成·O₂^-,有效抑制载流子复合.P 3p与O 2p轨道杂化能级与氧空位能级共同作用导致带隙窄化,改善光吸收性能.Yb-P共掺杂能进一步抑制光生e^-/h⁺复合,提高量子效率;进一步增加表面羟基,有利于俘获光生h⁺生成强氧化性羟基自由基.上述因素均有利于提高光催化活性.

关键词: TiO₂, 水热, 水解, 纳米材料, TiCl₄, Yb-P共掺杂