| Pd/MnOx+Pd/γ-Al2O3整体式催化剂降解地表臭氧 |
| Pd/MnOx+Pd/γ-Al2O3 Monolith Catalysts for Ground-Level Ozone Decomposition |
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| 摘要: 用高锰酸钾与硝酸锰氧化还原反应制备了高活性的氧化锰(MnOx)催化组分,用胶溶法制备了高比表面积的γ-Al2O3载体,分别用等体积浸渍法制备了Pd/MnOx和Pd/γ-Al2O3催化剂,然后将两者机械混合涂覆于堇青石上制得Pd/MnOx+Pd/γ-Al2O3整体式催化剂。采用X射线衍射(XRD)、X射线光电子能谱(XPS)、程序升温还原(H2-TPR)和低温N2吸附-脱附对催化剂进行了表征。考察了在300至700℃焙烧MnOx对催化剂降解地表O3活性的影响。结果表明,Pd和MnOx之间存在协同作用;MnOx焙烧温度对催化剂活性有一定的影响,其中以600℃焙烧时催化剂的活性最高,O3的起始(12℃)转化率达到88%,完全转化温度为18℃。MnOx的物相和催化剂表面的吸附氧物种对催化活性影响较大,适当比例的MnO2和Mn2O3共存有利于O3分解,表面吸附氧为O3分解的活性氧物种。 |
| 关键词: 锰氧化物 钯 臭氧 催化降解 焙烧温度 |
| 基金项目: 四川大学化学学院基地能力提高项目基金(No.J1103315)资助项目。 |
| Abstract: Ahighly active MnOx materials were prepared by an oxidation-reduction reaction between KMnO4 and Mn(NO3)2. The γ-Al2O3 support with large surface area was synthesized by the peptizing method. Subsequently, Pd was loaded on MnOx and γ-Al2O3 by incipient wetness impregnation, respectively. Then, the Pd/MnOx and Pd/γ-Al2O3 were mixed and coated on the cordierite. Finally, the Pd/MnOx+Pd/γ-Al2O3 monolithic catalysts were obtained. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature-programmed reduction (H2-TPR) and low temperature N2 adsorption/desorption measurement, respectively. Asynergetic effect took place between Pd and MnOx when O3 was decomposed on the surface of the Pd/MnOx+Pd/γ-Al2O3 catalysts. The effect of calcination temperature on the catalytic performance for the decomposition of ground-level ozone was investigated. It revealed that the activity of catalysts was considerably influenced by the calcination temperature of MnOx. When the MnOx was calcined at 600 ℃, the catalyst had the highest activity, where ozone conversion reached 88% at 12 ℃ and it was completely decomposed at 18 ℃. The results show that catalytic activity mainly depends on the MnOx phase and oxygen species adsorbed on the surface of catalysts. The MnO2 and Mn2O3 with proper proportion can efficiently promote the decomposition of ozone. And oxygen adsorbed on the surface of catalysts is active oxygen species during ozone decomposition. |
| Keywords: manganese oxide palladium ozone catalytic decomposition calcination temperature |
| 投稿时间：2013-02-25 修订日期：2013-06-14 |
| 摘要点击次数: 1630 |
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| 周丽娜,陈耀强,任成军,龚茂初.Pd/MnOx+Pd/γ-Al2O3整体式催化剂降解地表臭氧[J].无机化学学报,2013,29(11):2363-2369. |
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