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Hierarchical macroparticles of ceria with tube-like shape – synthesis and properties
CrystEngComm ( IF 2.6 ) Pub Date : 2021-08-17 , DOI: 10.1039/d1ce00755f Małgorzata A. Małecka 1 , Piotr Woźniak 1
CrystEngComm ( IF 2.6 ) Pub Date : 2021-08-17 , DOI: 10.1039/d1ce00755f Małgorzata A. Małecka 1 , Piotr Woźniak 1
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This work presents the results of a multi-technique (HRTEM – high resolution transmission electron microscopy, EDX – energy-dispersive X-ray spectroscopy, XRD – X-ray diffraction and H2-TPR – temperature programmed reduction by H2) study on the hierarchical organization of Yb-doped ceria nanocrystals (Ce1−xYbxO2−x/2) into tube-like macro-particles. Hierarchically organized ceria-based mixed oxides (macroparticles) were prepared by a wet chemical method. It was observed that the predetermined shape of the investigated macroparticles was kept up to x = ∼0.2. Above this value, additional forms (like large, un-shapely aggregates of the nanoparticles) were created. A very important feature of these materials is the very high shape stability, even at high temperatures. The overall shape of the macroparticles remained unchanged even at up to 900 °C. Moreover, the effect of the hierarchical arrangement of nanocrystallites into the tube-like macroparticles on the activity for propane oxidation and soot combustion reactions has been investigated. The CeO2 nanopowder (prepared by the microemulsion technique) was used as an example of an unorganized structure. It was concluded that the presence of a 3D structure composed of CeO2 nanocrystals significantly improves the catalytic activity of the tube-like material in comparison to the ceria nanopowder. The investigated oxides are good candidates for catalysts of soot oxidation. For the tube-like ceria, the temperature of half oxidation (T50% = 468 °C) was 62 °C lower than that for the nanopowder (T50% = 538 °C) and 103 °C lower than that for non-catalysed oxidation (T50% = 592 °C). Moreover, introduction of Yb3+ ions into the ceria matrix led to further improvement of the propane oxidation performance. For the tube-like Ce0.9Yb0.1O1.95, the temperature of half oxidation (T50% = 455 °C) was 40 °C lower than that for undoped tube-like CeO2 (T50% = 495 °C) and 95 °C lower than that for the ceria nanopowder (T50% = 550 °C).
中文翻译：
具有管状形状的氧化铈分级大粒子——合成和性质
这项工作提出了多技术的结果（HRTEM -高分辨率透射电子显微镜，EDX -能量色散型X射线光谱，XRD - X射线衍射和H 2 -TPR -温度程序由H还原2）的研究上Yb 掺杂的氧化铈纳米晶体 (Ce 1− x Yb x O 2− x /2 )分层组织成管状大颗粒。通过湿化学方法制备分层组织的基于氧化铈的混合氧化物（大颗粒）。据观察，所研究的大粒子的预定形状保持在x= ~0.2。在这个值之上，产生了额外的形式（如纳米颗粒的大的、不规则的聚集体）。这些材料的一个非常重要的特性是非常高的形状稳定性，即使在高温下也是如此。即使在高达 900 °C 的温度下，大颗粒的整体形状也保持不变。此外，研究了纳米微晶分级排列成管状大颗粒对丙烷氧化和烟灰燃烧反应活性的影响。CeO 2纳米粉末（通过微乳液技术制备）被用作无组织结构的例子。得出的结论是，存在由 CeO 2组成的 3D 结构与氧化铈纳米粉末相比，纳米晶体显着提高了管状材料的催化活性。所研究的氧化物是碳烟氧化催化剂的良好候选者。对于管状氧化铈，半氧化温度（T 50% = 468°C）比纳米粉体（T 50% = 538°C）低62°C，比非纳米粉体低103°C。催化氧化 ( T 50% = 592 °C)。此外，将Yb 3+离子引入氧化铈基质导致丙烷氧化性能的进一步提高。对于管状的 Ce 0.9 Yb 0.1 O 1.95，半氧化温度 ( T50% = 455 °C) 比未掺杂的管状 CeO 2 ( T 50% = 495 °C)低 40 °C，比氧化铈纳米粉末 ( T 50% = 550 °C)低 95 °C.
更新日期：2021-09-09
中文翻译：
具有管状形状的氧化铈分级大粒子——合成和性质
这项工作提出了多技术的结果（HRTEM -高分辨率透射电子显微镜，EDX -能量色散型X射线光谱，XRD - X射线衍射和H 2 -TPR -温度程序由H还原2）的研究上Yb 掺杂的氧化铈纳米晶体 (Ce 1− x Yb x O 2− x /2 )分层组织成管状大颗粒。通过湿化学方法制备分层组织的基于氧化铈的混合氧化物（大颗粒）。据观察，所研究的大粒子的预定形状保持在x= ~0.2。在这个值之上，产生了额外的形式（如纳米颗粒的大的、不规则的聚集体）。这些材料的一个非常重要的特性是非常高的形状稳定性，即使在高温下也是如此。即使在高达 900 °C 的温度下，大颗粒的整体形状也保持不变。此外，研究了纳米微晶分级排列成管状大颗粒对丙烷氧化和烟灰燃烧反应活性的影响。CeO 2纳米粉末（通过微乳液技术制备）被用作无组织结构的例子。得出的结论是，存在由 CeO 2组成的 3D 结构与氧化铈纳米粉末相比，纳米晶体显着提高了管状材料的催化活性。所研究的氧化物是碳烟氧化催化剂的良好候选者。对于管状氧化铈，半氧化温度（T 50% = 468°C）比纳米粉体（T 50% = 538°C）低62°C，比非纳米粉体低103°C。催化氧化 ( T 50% = 592 °C)。此外，将Yb 3+离子引入氧化铈基质导致丙烷氧化性能的进一步提高。对于管状的 Ce 0.9 Yb 0.1 O 1.95，半氧化温度 ( T50% = 455 °C) 比未掺杂的管状 CeO 2 ( T 50% = 495 °C)低 40 °C，比氧化铈纳米粉末 ( T 50% = 550 °C)低 95 °C.
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