TY - JOUR

T1 - Ca-doped rare earth perovskite materials for tailored exsolution of metal nanoparticles

AU - Lindenthal, Lorenz

AU - Ruh, Thomas

AU - Rameshan, Raffael

AU - Summerer, Harald

AU - Nenning, Andreas

AU - Herzig, Christopher

AU - Löffler, Stefan

AU - Limbeck, Andreas

AU - Opitz, Alexander Karl

AU - Blaha, Peter

AU - Rameshan, Christoph

N1 - Publisher Copyright: © 2020 International Union of Crystallography. All rights reserved.

PY - 2020/12/1

Y1 - 2020/12/1

N2 - 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.

AB - 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.

KW - catalysis

KW - DFT

KW - nanoparticle exsolution

KW - perovskite

UR - http://www.scopus.com/inward/record.url?scp=85097575230&partnerID=8YFLogxK

U2 - 10.1107/S2052520620013475

DO - 10.1107/S2052520620013475

M3 - Article

C2 - 33289717

AN - SCOPUS:85097575230

VL - 76.2020

SP - 1055

EP - 1070

JO - Acta crystallographica Section B: Structural science, crystal engineering and materials

JF - Acta crystallographica Section B: Structural science, crystal engineering and materials

SN - 2052-5192

ER -