TiCl_4水解法水热制备Yb-P-TiO_2纳米光催化剂及共掺杂的协同机制  

Hydrothermal preparation of Yb-P-TiO_2 nano-photocatalyst from TiCl_4 hydrolysis and synergetic mechanism of co-doping

作　　者：姜洪泉[1] 李振宇[1] 王雪峰[1] 李井申[1] 王巧凤[1] 

机构地区：[1]哈尔滨师范大学功能材料设计合成与绿色催化黑龙江省高校重点实验室,黑龙江哈尔滨150025

出　　处：《化工学报》2014年第12期5030-5038,共9页CIESC Journal

基　　金：黑龙江省自然科学基金项目(E201323);哈尔滨市科技创新人才专项基金项目(2013RFXXJ081);黑龙江省教育厅科学技术研究项目(12531213)~~

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·O-2,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。Mesoporous Yb-P-co-doped anatase-TiO2 nano-sheets were synthesized from TiCl_4 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-TiO_2 〈 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^-l） 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. Yb^3＋ ions could capture photo-generated electrons to form Yb^2＋, which intum 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.

关 键 词：TIO2 水热 水解 纳米材料 TICL4 Yb-P共掺杂 

分 类 号：O643[理学—物理化学]