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化学学报
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化学学报 ›› 2005, Vol. 63 ›› Issue (9): 797-801. 上一篇    下一篇

研究论文

铂修饰的稀土掺杂TiO2的光催化制氢活性

王添辉1，李越湘*1，彭绍琴1，吕功煊2，李树本2   

  1. (1南昌大学化学系 南昌 330047)
    (2中国科学院兰州化学物理研究所 羰基合成与选择氧化国家重点实验室 兰州 730000)
  • 投稿日期:2004-09-28 修回日期:2005-01-18 发布日期:2010-12-10
  • 通讯作者: 李越湘

Activity of Rare Earth Doped TiO2 Deposited with Pt for Photocatalytic Hydrogen Generation

WANG Tian-Hui1, LI Yue-Xiang*1, PENG Shao-Qin1, LÜ Gong-Xuan2, LI Shu-Ben2   

  1. (1 Department of Chemistry, Nanchang University, Nanchang 330047)
    (2 State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics,
    Chinese Academy of Sciences, Lanzhou 730000)
  • Received:2004-09-28 Revised:2005-01-18 Published:2010-12-10
  • Contact: LI Yue-Xiang

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采用溶胶-凝胶浸渍法和光沉积法制备了系列Pt/RE/TiO2纳米光催化剂, 通过XRD和电化学等手段进行了表征. 以甲醛为电子给体, 考察了光催化剂在紫外光照射下的制氢活性. 稀土掺杂提高了Pt/TiO2光催化制氢活性, 其顺序分别为La/TiO2＞Sm/TiO2＞Eu/TiO2＞Dy/TiO2＞Er/TiO2. 掺入稀土元素后, 阻止了TiO2从锐钛矿晶型向金红石晶型的转变, 这是光催化剂活性提高的原因之一. 计算晶格畸变应力e数据表明, Ti4＋可能反掺入了表面稀土氧化物的晶格中. 电化学实验表明稀土掺杂TiO2的平带电位负移, 其原因可解释为晶格畸变促使费米能级升高, 导致催化剂导带的平带电位负移, 因此导带上被激发电子具有更强的还原能力, 从而有利于光催化制氢活性的提高.

关键词: 二氧化钛, 光催化, 稀土, 晶格畸变, 平带电位, 制氢

A series of Pt/RE/TiO2 photocatalysts were prepared by sol-gel impregnation and photodepositon process, and characterized by means of X-ray diffraction and electrochemistry. As a model reaction, photocatalytic hydrogen generation from water using formaldehyde as electron donor was investigated. It has been found that the activities of all rare earth doped TiO2 samples have been increased compared to those of pure TiO2, and the order was La/TiO2＞Sm/TiO2＞Eu/TiO2＞Dy/TiO2＞Er/TiO2. It was shown that the transformation from anatase to rutile was prevented, which could enhance the activities of the photocatalysts. The data of lattice distortion implied that Ti4＋could enter (anti-dope) into rare earth oxide that existed on the surface of titanium dioxide. The data of electrochemistry experiment showed that the flat-band potential of conduction of RE/TiO2 has been shifted negatively. The lattice distortion raised the Fermi level, which caused flat-band potential of the conduction of TiO2 to shift negatively. As a result, the photoinduced electrons of the conduction band had stronger reductive capability and the photocatalytic activity of hydrogen generation was improved.

Key words: titanium dioxide, photocatalysis, rare earth, lattice distortion, flat-band potential, hydrogen generation