Nickel based mesoporous silica-ceria-zirconia composite for carbon dioxide reforming of methane
Nickel based mesoporous silica-ceria-zirconia composite for carbon dioxide reforming of methane
复制标题
用于甲烷二氧化碳重整的镍基介孔二氧化硅-二氧化铈-氧化锆复合材料
DOI：
10.1016/j.apcata.2016.04.020
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发表时间：
2016
影响因子：
5.5
通讯作者：
Chou Lingjun
中科院分区：
文献类型：
--
作者：
Xiang Xianmei;Zhao Huahua;Yang Jian;Zhao Jun;Yan Liang;Song Huanling;Chou Lingjun
通过改进的蒸发诱导自组装策略（EISA）制备了一系列具有可变Si/（Ce + Zr）摩尔比的介孔二氧化硅-二氧化铈-氧化锆复合材料（Si-MCeZr）。 TEM 和 XRD 测量表明，Si-MCeZr 框架由二氧化铈-氧化锆固溶体晶体纳米颗粒和充当连接纳米晶体的胶水的无定形二氧化硅制成。进一步的热处理（700°C）表明Si-MCeZr的热稳定性高于无Si介孔氧化铈-氧化锆固溶体（MCeZr）的热稳定性。这可能是由于Si的引入起到了关键作用，Si通过抑制纳米颗粒的生长和二氧化锆固溶体纳米颗粒的结晶来提高热稳定性。此外，Si-MCeZr材料用作载体制备用于CH4的CO2重整的镍基催化剂(Ni/Si-MCeZr)。 XPS分析表明，Ni/Si-MCeZr中表面氧空位的浓度随着Si/(Ce + Zr)摩尔比的增加而增加。长期重整测试表明，与无硅镍基催化剂（Ni/MCeZr）相比，Ni/Si-MCeZr的催化稳定性得到了提高。结果表明，耐久性的提高可能源于Ni/Si-MCeZr中更高浓度的氧空位、更快的氧迁移率和改善的镍分散性，这在很大程度上有助于提高重整反应中的催化活性和除焦能力，稳定性测试前后催化剂的TG-DSC和XRD表征证实了这一点。
A series of mesoporous silica-ceria-zirconia composite (Si-MCeZr) with variable Si/(Ce + Zr) molar ratios are prepared by improved evaporation induced self-assemble strategy (EISA). TEM and XRD measurements show that the Si-MCeZr frameworks are made of ceria-zirconia solid solutions crystalline nanoparticles and the amorphous silica that serves as glue connecting the nanocrystals. The further heating treatment (700 °C) reveals that the thermal stability of Si-MCeZr is higher than that of Si free mesoporous ceria-zirconia solid solution (MCeZr). This might be due to the key role of the introduction of Si, which improves the thermal stability via inhibiting the growth of nanoparticles and crystallization of ceria-zirconia solid solution nanoparticles. Furthermore, the Si-MCeZr materials are applied as support to prepare nickel based catalysts (Ni/Si-MCeZr) for CO2reforming of CH4. The XPS analyses show that the concentration of surface oxygen vacancies in Ni/Si-MCeZr increases with the increasing of Si/(Ce + Zr) molar ratios. The long term reforming test demonstrates that the catalytic stability of Ni/Si-MCeZr is improved compared to Si free nickel based catalyst (Ni/MCeZr). The obtained results indicate that enhanced durability may originate from the higher concentration of oxygen vacancies, more rapid oxygen mobility and improved nickel dispersion in Ni/Si-MCeZr, which contribute largely to higher catalytic activity and decoking ability in reforming reaction, as confirmed by TG-DSC and XRD characterizations of catalysts before and after stability tests.