Fabrication of Ag-CeO2 core-shell nanospheres with enhanced catalytic performance due to strengthening of the interfacial interactions
Fabrication of Ag-CeO2 core-shell nanospheres with enhanced catalytic performance due to strengthening of the interfacial interactions
复制标题
制备 Ag-CeO2 核壳纳米球，由于增强了界面相互作用而具有增强的催化性能
DOI：
10.1039/c2jm16701h
复制
发表时间：
2012-01-01
影响因子：
--
通讯作者：
Li, Guangshe
中科院分区：
文献类型：
--
作者：
Zhang, Jun;Li, Liping;Li, Guangshe
界面相互作用经常出现在人类医疗器械、混合太阳能电池和催化剂中。然而，在为许多技术应用定制材料特性时，缺乏对这些相互作用的控制。作为一个案例研究，我们报道了合成Ag-CeO 2核壳纳米球的目的是加强界面相互作用，以提高催化性能。所有的核-壳纳米球通过无表面活性剂的方法与随后的退火氧化还原反应合成。系统的样品表征表明，直径为50-100 nm的金属Ag核被30-50 nm壳厚的CeO 2组装纳米粒子包裹，形成纳米级的核壳结构。Ag核和CeO 2壳之间的界面相互作用通过退火得到加强，令人惊讶的是，随后产生氧空位，为氧物种提供丰富的吸收位点。结果，氧溢出的温度降低到79 ℃，并且催化性能异常增强，如在120 ℃下完全CO氧化所示，即使当反应时间超过100小时时也没有失活的迹象。反应产物从核-壳纳米球的表面快速脱附，这解释了它们在催化反应期间的上级稳定性。
Interfacial interactions are often found in human medical devices, hybrid solar cells, and catalysis. However, there is a lack of control of these interactions when tailoring the materials properties for many technological applications. As a case study, we reported on the synthesis of Ag-CeO2 core-shell nanospheres with the aim of strengthening the interfacial interactions to give enhanced catalytic performance. All core-shell nanospheres were synthesized by a surfactant-free method with a subsequent annealing redox reaction. Systematic sample characterizations indicate that metallic Ag cores with a diameter of 50-100 nm were wrapped by assembled nanoparticles of CeO2 with a shell thickness of 30-50 nm to form a nano-scale core-shell structure. The interfacial interactions between the Ag core and CeO2 shell were strengthened by annealing, surprisingly, as followed by generation of oxygen vacancies to provide abundant of absorption sites for oxygen species. As a consequence, the temperature for oxygen spilling was lowered to 79 degrees C, and the catalytic performance was abnormally enhanced, as indicated by complete CO oxidation at 120 degrees C with no sign of deactivation, even when the reaction time is beyond 100 h. The reaction products were desorbed quickly from the surfaces of the core-shell nanospheres, which accounts for their superior stability during catalytic reactions.