掺杂剂
兴奋剂
材料科学
钙钛矿(结构)
金属
氧化物
纳米颗粒
催化作用
晶体结构
化学工程
纳米技术
结晶学
化学
冶金
光电子学
工程类
生物化学
作者
Lorenz Lindenthal,Thomas Ruh,Raffael Rameshan,Harald Summerer,Andreas Nenning,Christopher Herzig,Stefan Löffler,Andreas Limbeck,Alexander Karl Opitz,Peter Blaha,Christoph Rameshan
出处
期刊:Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
[Wiley]
日期:2020-11-14
卷期号:76 (6): 1055-1070
被引量:15
标识
DOI:10.1107/s2052520620013475
摘要
Perovskite-type oxide materials (nominal composition ABO3) are a very versatile class of materials, and their properties are tuneable by varying and doping A- and B-site cations. When the B-site contains easily reducible cations (e.g. Fe, Co or Ni), these can exsolve under reducing conditions and form metallic nanoparticles on the surface. This process is very interesting as a novel route for the preparation of catalysts, since oxide surfaces decorated with finely dispersed catalytically active (often metallic) nanoparticles are a key requirement for excellent catalyst performance. Five doped perovskites, namely, La0.9Ca0.1FeO3-δ, La0.6Ca0.4FeO3-δ, Nd0.9Ca0.1FeO3-δ, Nd0.6Ca0.4FeO3-δ and Nd0.6Ca0.4Fe0.9Co0.1O3-δ, have been synthesized and characterized by experimental and theoretical methods with respect to their crystal structures, electronic properties, morphology and exsolution behaviour. All are capable of exsolving Fe and/or Co. Special emphasis has been placed on the influence of the A-site elemental composition on structure and exsolution capability. Using Nd instead of La increased structural distortions and, at the same time, hindered exsolution. Increasing the amount of Ca doping also increased distortions and additionally changed the Fe oxidation states, resulting in exsolution being shifted to higher temperatures as well. Using the easily reducible element Co as the B-site dopant significantly facilitated the exsolution process and led to much smaller and homogeneously distributed exsolved particles. Therefore, the Co-doped perovskite is a promising material for applications in catalysis, even more so as Co is catalytically a highly active element. The results show that fine-tuning of the perovskite composition will allow tailored exsolution of nanoparticles, which can be used for highly sophisticated catalyst design.
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