催化学报

催化学报 ›› 2015, Vol. 36 ›› Issue (12): 2178-2185.DOI: 10.1016/S1872-2067(15)61009-9

• 论文 • 上一篇    下一篇

棒状结构Pt/PbWO4微米晶的合成、表征及其高光催化性能

余长林a, 白羽a, 何洪波a, 范文宏b, 朱丽华a, 周晚琴a,c   

  1. a 江西理工大学冶金与化学工程学院, 江西赣州 341000;
    b 北京航空航天大学化学与环境学院环境科学与工程系, 北京 100191;
    c 福州大学能源与环境光催化国家重点实验室, 福建福州 350002
  • 收稿日期:2015-08-15 修回日期:2015-11-04 出版日期:2015-12-02 发布日期:2015-12-07
  • 通讯作者: 余长林, 范文宏
  • 基金资助:

    国家自然科学基金(21067004, 21567008, 21263005);江西省自然科学基金(20133BAB21003);江西省大学学生创新创业训练计划(201310407046);江西省高等学校科技落地项目(KJLD14046);江西省青年科学家项目(20122BCB23015);江西省远航工程.

Synthesis, characterization and photocatalytic performance of rod-shaped Pt/PbWO4 composite microcrystals

Changlin Yua, Yu Baia, Hongbo Hea, Wenhong Fanb, Lihua Zhua, Wanqin Zhoua,c   

  1. a School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China;
    b Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, China;
    c State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, Fujian, China
  • Received:2015-08-15 Revised:2015-11-04 Online:2015-12-02 Published:2015-12-07
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21067004, 21567008, 21263005), Project of Jiangxi Province Natural Science Foundation China (20133BAB21003), Training Programs of Innovation and Entrepreneurship for Undergraduates of Jiangxi Province (201310407046), The Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province (KJLD14046), and Young Scientist Training Project of Jiangxi Province (20122BCB23015), Yuanhang Engineering of Jiangxi Province.

PDF

775

摘要：

PbWO4是一类重要的半导体,广泛运用于高能物理领域无机闪烁晶体.它具有许多独特的物理性能,如衰减时间短(10ns)、能量密度高(8.28cm3)、低光产率(300photons/MeV)、短辐射长度(0.9cm)和高抗辐照损伤等.PbWO4纳米晶体的激子荧光、热荧光和其它光学性能主要取决PbWO4晶体的形貌和微观结构.目前已经合成了不同结构的PbWO4纳米/微米晶体,如四角双锥微米晶、微米球、纳米棒、纳米纺垂体等.近年来,PbWO4的光催化性能也引起人们的重视.研究发现,PbWO4晶体的光催化性能和其形貌、微观结构密切相关.如在不同形貌的十四面体、三维多尺度微米球和纳米颗粒中,PbWO4微米球表现了极高的光催化活性.此外,PbWO4微米球由于密度大,非常容易分离,从而有利于其回收利用,在循环使用时具有很高的稳定性.因此,合成具有特殊形貌的PbWO4纳米/微米晶体具有重要的理论和现实意义.此外,合成贵金属/半导体复合纳米结构是提高光催化性能的另一有效策略.在贵金属/半导体复合纳米结构中,光生电子(e-)和(h+)的复合可以在很大程度上得到抑制,因为光生e-可以快速地迁移至贵金属颗粒中心,从而加速e-和h+的分离.
本文利用水热结合焙烧法首先合成了长度大于1μm的棒状PbWO4微米晶.然后利用光化学沉积法,在PbWO4微米晶表面沉积不同含量(0.5wt%,1wt%,和2wt%)的Pt纳米粒子.利用X射线衍射(XRD)、N2物理吸附、扫描电镜(SEM)、透射电镜(TEM)、光电子能谱(XPS)、光致发光谱(PL)和紫外-可见漫反射吸收光谱(UV-Vis DRS)等手段对所制PbWO4和Pt/PbWO4进行了表征.表征结果表明,合成的PbWO4和Pt/PbWO4的比表面积很小(1.5-1.9m2/g),沉积的Pt纳米粒子为金属态.UV-Vis DRS测试表明,沉积的Pt纳米粒子在光照下可以产生表面等离子共振,促进可见光的吸收.另外,PL的结果则证实Pt纳米粒子的存在还可抑制PbWO4晶体在光照下产生的光生e-和h+的分离.而XRD和高分辨TEM分析表明PbWO4微米棒的晶体生长方向为(-102)晶体方向.电子选区衍射表明,棒状PbWO4微米晶具有极高的结晶度.以氙灯为光源进行了光催化降解染料酸性橙II的光催化性能测试.结果表明,当沉积1-2wt%Pt纳米粒子时,可使光催化活性提高2倍左右.另外,Pt/PbWO4微米棒的密度较大,非常容易进行离心分离催化剂及其循环使用.在第一次使用时酸性橙II的降解率为93%,而在第四次使用时酸性橙II的降解率仍维持在88%,表现出很好的光催化稳定性.Pt/PbWO4具有很高的光催化活性的原因,一方面是由于其具有很高的结晶度和独特的棒状结构,另一方面是由于沉积的Pt纳米粒子在光照下可以产生表面等离子共振,促进了可见光的吸收和光生e-与h+的分离.

关键词: 棒状, 钨酸铅微米晶, 铂纳米粒子, 光催化活性, 光催化稳定性, 表面等离子体, 电子-空穴分离

Abstract:

Rod-shaped PbWO4 microcrystals of length >1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles (NPs) of different contents (0.5 wt%, 1 wt% and 2 wt%) were subsequently deposited on the PbWO4 microcrystals, producing robust Pt/PbWO4 composite microcrystals. The PbWO4 microcrystals and Pt/PbWO4 photocatalysts were characterized by X-ray diffraction, N2 sorption measurements, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron, photoluminescence, Fourier-transform infrared, and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbWO4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance (SPR), which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an ~2 times increase in photocatalytic activity, compared with the activity of Pt/PbWO4. The crystal structure and high crystallinity of PbWO4 resulted in its favorable photocatalytic property, and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes, which further promoted the photocatalytic reaction.

Key words: Rod-shaped, Lead tungstate microcrystals, Platium nanoparticles, Photocatalytic activity, Photocatalytic stability, Surface plasma, Electron-hole separation