| CoOx改性TiO2光催化剂的制备、优化及其光催化分解水析氢性能研究 |
| The Preparation, Optimization and Photocatalytic Properties of CoOx-modified TiO2 Photocatalysts for Hydrogen Generation from Photocatalytic Water Splitting |
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| 摘要: 利用热分解法制备了不同掺杂量的CoOx-TiO2系列光催化剂, 并优化了制备方法。在用XRD、TEM和XPS等技术对催化剂表征的基础上，探讨了乙醇作为电子给体时CoOx改性对P25-TiO2光催化分解水析氢性能的影响。本文还利用连续瞬态电流-时间响应和循环伏安法等电化学方法，考察了CoOx-TiO2改性系列光催化剂光照条件下电流响应强度、起始光电响应特性差别及光催化析氢电位变化等光电化学性能。光催化性能实验结果表明，适当掺杂CoOx(110～400 ℃焙烧时最佳掺杂量约为0.4wt% Co，500 ℃焙烧时最佳掺杂量约为0.6～0.8wt% Co)能够显著地提高TiO2析氢光催化性能，产氢速率提高2个数量级。另外在适当温度下的热处理，能够改善催化剂光催化性能(最佳处理温度为300～400 ℃)。光电化学性能评价结果表明，适当掺杂CoOx和适当温度下焙烧能在催化剂表面形成较多的析氢活性物种——含钴复合物，能有效增强催化剂光电流响应强度，并使得析氢光还原电位向有利于析氢方向位移。高含量掺杂CoOx会在催化剂表面形成某种碳化物物种，大量含钴复合物活性中心的出现会降低光吸收效率，增加TiO2表面光生电子-空穴复合率而使催化剂失去析氢光催化性能。 |
| 关键词: 光催化 光电化学 CoOx-TiO2 制氢 |
| 基金项目: |
| Abstract: The CoOx-modified-TiO2 photocatalysts have been prepared. The preparation method has been optimized. The catalysts were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectrometer. The results showed that a small part of Co2+ metal ion was doped on the surface of TiO2 in CoOx-TiO2 form. The photoelectrochemical and photocatalytic performance for hydrogen generation from water (ethanol as electron donor) were investigated. The results of photocatalytic hydrogen production showed that the Co content and optimized temperature had an obvious effect on the photocatalytic hydrogen generation rate. The optimal content and temperature were 0.4wt% Co and 300～400 ℃, respectively. In an optimal condition, CoOx doping could obviously enhance the hydrogen generation rate from water with a satisfied stability during the experimental period. The hydrogen production rates have increased over two order of magnitude (from 2.8 × 10-3 mol·h-1 to 4.0 × 10-1 mol·h-1). The results of the photoelectrochemical performance showed that an appropriate amount of CoOx doping on photocatalyst could produce phtocatalytic reaction sites — CoOx-TiO2 complexing compounds on surface of TiO2, and enhance the photocurrent response. But with a higher doping content, large numbers of CoOx-TiO2 complexing compounds and a new kind of carbide compounds — probably CoxC or TiC were produced. They became the reactive centers of the photoelectron-hole pairs recombination, which in turn reduced the ability of the photoabsorption and the photocatalytic hydrogen generation. |
| Keywords: CoOx-doped TiO2 photocatalysis hydrogen production photoelectrochemistry |
| 投稿时间：2004-07-26 修订日期：2004-10-30 |
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| 吴玉琪,吕功煊,李树本.CoOx改性TiO2光催化剂的制备、优化及其光催化分解水析氢性能研究[J].无机化学学报,2005,21(3):309-314. |
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