催化学报 ›› 2018, Vol. 39 ›› Issue (3): 431-437.DOI: 10.1016/S1872-2067(18)63043-8

• 论文 • 上一篇    下一篇

TiB2/均相硼掺杂TiO2核/壳结构提升光催化氧化水产氧活性

杨勇强a, 康宇阳a,b, 刘岗a,b, 成会明a,c,d   

  1. a 中国科学院金属研究所沈阳材料科学国家研究中心, 辽宁沈阳 110016;
    b 中国科学技术大学材料科学学院, 辽宁沈阳 110016;
    c 清华大学清华-伯克利深圳研究院, 广东深圳 518055;
    d 阿卜杜拉国王科技大学卓越环境研究中心, 吉达 21589, 沙特阿拉伯
  • 收稿日期:2018-02-01 修回日期:2018-02-03 出版日期:2018-03-18 发布日期:2018-03-10
  • 通讯作者: 刘岗
  • 基金资助:

    国家自然科学基金(51702327,51521091);科技部国家重点基础研发计划项目(2014CB239401);中国科学院前沿科学重点研究计划(QYZDB-SSW-JSC039);葛庭燧奖研金;牛顿高级学者项目.

Homogeneous boron doping in a TiO2 shell supported on a TiB2 core for enhanced photocatalytic water oxidation

Yongqiang Yanga, Yuyang Kanga,b, Gang Liua,b, Hui-Ming Chenga,c,d   

  1. a Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, Liaoning, China;
    b School of Materials Science, University of Science and Technology of China, Shenyang 110016, Liaoning, China;
    c Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, Guangdong, China;
    d Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah 21589, Saudi Arabia
  • Received:2018-02-01 Revised:2018-02-03 Online:2018-03-18 Published:2018-03-10
  • Contact: 10.1016/S1872-2067(18)63043-8
  • Supported by:

    This work was supported by the National Science Foundation of China (51702327, 51521091), the Major Basic Research Program, Ministry of Science and Technology of China (2014CB239401), the Key Research Program of Frontier Sciences CAS (QYZDB-SSW-JSC039), the awards of the IMR SYNL-T.S. Kê Research Fellowship, and the Newton Advanced Fellowship.

摘要:

光催化可实现污染物降解、分解水制氢和CO2还原等多种氧化还原反应,因而受到了广泛关注.光催化材料中光生电荷的数目与氧化还原能力直接影响光催化反应效率,在许多光催化反应中,光生空穴氧化反应被认为速控步骤.以光催化分解水为例,质子的还原是单电子过程,水氧化产生氧气则涉及四个电子.空穴的高能量不仅可赋予其高的氧化能力,还能提高其迁出表面的能力,因此具有重要研究价值.
我们组的前期工作表明,以TiB2作为前驱体,采用水热合成和焙烧两步法可制备出间隙硼掺杂的金红石相或锐钛矿相TiO2,间隙硼掺杂可显著降低价带顶,提升光催化氧化水产氧性能.然而,在已有的结果中,间隙硼掺杂浓度在TiO2中均呈现从内向外逐渐增加的梯度分布,这意味着硼掺杂浓度有限,且表层更低的价带顶不利于体相光生空穴向表面迁移,因此亟需实现TiO2中均相的间隙硼掺杂.
本文以湿化的氩气为水解环境,将水解过程限域在TiB2的表面以减少硼原子流失;同时提高水解温度,使残留的硼原子形成间隙掺杂,避免其在二次焙烧时扩散,从而在TiB2核的表面所形成的TiO2壳层中实现均相间隙硼掺杂,显著提高了光催化氧化水产氧活性.多种表征结果表明,直径约为6-10 μm的TiB2核表面形成了厚约400 nm的TiO2壳层,在TiO2/TiB2中TiO2壳层重量比约为30%,TiO2壳层中锐钛矿相TiO2占比为65 wt%,金红石相TiO2占比为35 wt%.TiO2壳层中间隙硼为均相分布,硼掺杂显著降低了价带顶位置,提高了光生空穴的氧化能力,从而使得TiB2/TiO2展现出比未掺杂的金红石、锐钛矿相及两者混合相的TiO2均具有更高的光催化氧化水产氧的能力.

关键词: 光催化, 产氧, 二氧化钛, 均相掺杂

Abstract:

Photocatalytic water oxidation for O2 evolution is known as a bottle neck in water splitting. Various strategies have been conducted to keep the energetics of photogenerated holes or to create more holes in the bulk to reach the surface for efficient photocatalytic water oxidation. Our previous study demonstrated the effectiveness of interstitial boron doping in improving photocatalytic water oxidation by lowering the valence band maximum of TiO2 with a concentration gradient of boron. In this study, homogeneous doping of interstitial boron was realized in a TiO2 shell with mixed anatase/rutile phases that was produced by the gaseous hydrolysis of the surface layer of TiB2 crystals in a moist argon atmosphere. Consequently, the homogeneous doping and lowered valence band maximum improved the energetics of holes for efficient photocatalytic water oxidation.

Key words: Photocatalysis, O2 evolution, TiO2, Homogenous doping