| 硼掺杂CeO2/TiO2光催化剂的制备及其活性研究 |
| 摘要点击 4201 全文点击 1938 投稿时间：2005-09-13 修订日期：2005-10-22 |
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| 中文关键词 硼掺杂 TiO2 CeO2 复合氧化物 光催化 |
| 英文关键词 boron doping TiO2 CeO2 mixed oxides photocatalysis |
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| 中文摘要 |
| 在三氯化钛和钛酸丁酯水解过程中引入硼酸、硝酸铈,制备了具有可见光活性的硼(B)掺杂CeO2/TiO2复合氧化物光催化剂,采用XRD、DRS、XPS等手段进行表征,以偶氮染料酸性红B为模型污染物评估了催化活性.结果表明,硝酸铈加入量影响催化剂的吸收带边,随用量增加,吸收带边红移至481nm(Ce/Ti=1.0,摩尔比),继续增加用量,吸收带边轻微蓝移.催化剂晶相组成与焙烧温度有关,500℃时焙烧样品主要由立方晶型CeO2和锐钛矿TiO2组成,焙烧温度高于700℃时,TiO2转化为金红石型,CeO2则无显著变化.随焙烧温度升高,催化剂吸收带边明显蓝移,综合考虑催化剂稳定性和太阳能利用,认为500℃焙烧较为合适.B1s XPS显示仅有少量B原子进入复合氧化物晶格取代了氧原子,主要以B2O3形式存在.酸性红B降解试验显示B掺杂CeO2/TiO2可以提高TiO2的催化活性,紫外光辐射10min最高可使96.0%的酸性红B分解,且反应彻底,表现出较强的氧化能力,但Ce/Ti>0.5(摩尔比)时催化活性显著下降. |
| 英文摘要 |
| Boron doped CeO2/TiO2 mixed oxides photocatalysts were prepared by adding boric acid and cerous nitrate during the hydrolyzation of titanium trichloride and tetrabutyl titanate.XRD,UV-Vis DRS and XPS techniques were used to characterize the crystalline structure,light absorbing ability and the chemical state of Boron element in the photocatalyst sample.The photocatalytic activities were evaluated by monitoring the degradation of acid red B under UV irradiation.These results indicate that the wavelengths at adsorbing edge are affected by the content of cerous nitrate and the maximum absorption wavelength is about 481nm when the mole ratio of Ce/Ti is 1.0.For higher dosage of Cerium,the absorbance edge shifts to blue slightly.The prepared photocatalyst is composed of anatase TiO2 and cubic CeO2 when calcined at 500℃.An increase in the calcination temperature transforms the crystalline structure of the titanium oxides from anatase to rutile,and has no obvious influence on crystalline structure of CeO2 but crystallites growth up.The absorbance edge decreases drastically with the increase of calcination temperature.With a view to the stability of photocatalyst and utilization of sun energy,500℃ of calcination temperature is recommended.The XP spectrum for B1s exhibits that only a few boron ions dope into titania and ceria matrix,others exist in B2O3.The photocatalytic activity increases with increase of cerous nitrate dosage,and decreases drastically due to higher dosage(the mol ratio of Ce/Ti>0.5).After 10min UV irradiation,96% of acid red B is degraded completely over photocatalyst under optimum reaction condition. |
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