| 焙烧温度对“软-硬”模板法制备的Pd/Ce0.65Zr0.35O2三效催化性能的影响 |
| Effect of Calcination Temperature on Three-Way Catalytic Performance of Pd/Ce0.65Zr0.35O2 Prepared by Soft-Hard Template Method |
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| 摘要: 采用"软-硬"模板法制备了具有高热稳定性的Ce0.65Zr0.35O2（CeZr）。考察了制备过程中焙烧温度对Ce0.65Zr0.35O2及其负载的单Pd三效催化剂（TWC）性能的影响。对样品进行了X射线衍射、比表面、拉曼光谱、X射线光电子能谱、储氧性能和H2程序升温还原性能测试。结果表明：焙烧温度显著影响催化剂的结构和性能。随着焙烧温度的增加，Ce0.65Zr0.35O2的比表面下降，但在1 000℃焙烧的样品比表面为61 m2·g-1，显著高于同温度下直接在空气中焙烧的样品。由于高温导致了物相重组，Ce0.65Zr0.35O2的储氧量和还原性能随着焙烧温度的增加而提升。由于高温烧结导致Pd分散性的下降，其负载的催化剂的还原性能随着焙烧温度的增加而下降，从而最终导致催化剂活性的降低。但在"软-硬"模板法中1 000℃焙烧的样品负载的催化剂依然显示出很好的三效催化性能，该催化剂上C3H8、CO和NO的起燃温度分别为274、175和133℃，显著低于同温度下空气中直接焙烧的样品负载的催化剂。催化剂的氧化还原性能和Pd的分散性是影响催化活性的主要因素。 |
| 关键词: Ce0.65Zr0.35O2 高热稳定性 催化性能 |
| 基金项目: 四川省教育厅（No.17ZB0457）资助项目。 |
| Abstract: High thermal stability Ce0.65Zr0.35O2(CeZr) was prepared by soft-hard template method. The influence of calcination temperature on properties of Ce0.65Zr0.35O2 and its corresponding Pd based three-way catalyst (TWC) was investigated. The samples were analyzed by X-ray diffraction, surface area analysis, Raman spectrum, X-ray photoelectron spectroscopy, oxygen storage capacity and H2-temperature-programmed reduction. The results indicate that the structure and redox properties are strongly influenced by calcination temperature. The structure properties, for instance, BET (Brunaner-Emmett-Teller) surface area declined along with the rise of temperature, but the BET surface area of the sample calcinated at 1 000℃ was 61 m2·g-1, which was significantly higher than that calcinated direct in air at the same temperature. The OSC and reduction property of Ce0.65Zr0.35O2 increased with the rise of calcination temperature because of phase rearrangement at high temperature. The redox property of their corresponding catalysts decreased due to descending of Pd dispersion, which results in decline of three-way catalytic activity at last. Although high temperature sintering led to decrease of catalytic performance, the catalyst prepared by soft-hard template method calcinated at 1 000℃ still had excellent activity. The light-off temperature for C3H8, CO and NO was 274, 175 and 133℃, respectively, which was significantly lower than catalyst calcined direct in air at the same temperature. Redox property and dispersity of Pd are significant factors affecting activity of catalyst. |
| Keywords: Ce0.65Zr0.35O2 high thermal stability catalytic performance |
| 投稿时间：2020-03-23 修订日期：2020-06-22 |
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| 黄利华,陈耀强.焙烧温度对“软-硬”模板法制备的Pd/Ce0.65Zr0.35O2三效催化性能的影响[J].无机化学学报,2020,36(11):2145-2156. |
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