Surface Segregation on Manganese Doped Ceria Nanoparticles and Relationship with Nanostability

Highly stable ceria nanoparticles (<11 nm) with different manganese contents were prepared by a coprecipitation method. The powders were studied by X-ray diffraction, transmission electron microscopy, electron energy loss spectroscopy, and water adsorption microcalorimetry. The data show that only a small fraction of the manganese ions dissolved into ceria fluorite structure as solid solution, and most segregated on the particles’ surface, causing decrease of the average surface energy of the particles with increasing dopant concentration. This was confirmed by direct surface energy measurements using water adsorption microcalorimetry, and has consequences for particle coarsening behavior. That is, the results explain why manganese doped ceria nanoparticles show stronger resistance to coarsening as compared to undoped ceria. The enthalpy of surface segregation of manganese was calculated and discussed as an important parameter to design highly metastable ceria nanoparticles on a thermodynamic basis.

[1]  R. Castro,et al.  Surface and grain boundary energies of tin dioxide at low and high temperatures and effects on densification behavior , 2014 .

[2]  R. Castro,et al.  Water Adsorption Microcalorimetry Model: Deciphering Surface Energies and Water Chemical Potentials of Nanocrystalline Oxides , 2014 .

[3]  R. Castro,et al.  Water adsorption and interface energetics of zinc aluminate spinel nanoparticles: Insights on humidity effects on nanopowder processing and catalysis , 2013 .

[4]  R. Castro.  On the thermodynamic stability of nanocrystalline ceramics , 2013 .

[5]  R. Castro,et al.  Analysis of Anhydrous and Hydrated Surface Energies of gamma-Al2O3 by Water Adsorption Microcalorimetry , 2012 .

[6]  A. Navrotsky,et al.  Enthalpies of formation and insights into defect association in ceria singly and doubly doped with neodymia and samaria , 2012 .

[7]  A. Navrotsky,et al.  Thermodynamics of manganese oxides: Effects of particle size and hydration on oxidation-reduction equilibria among hausmannite, bixbyite, and pyrolusite , 2012 .

[8]  C. Schuh,et al.  Design of Stable Nanocrystalline Alloys , 2012, Science.

[9]  S. C. Parker,et al.  Water Adsorption and Its Effect on the Stability of Low Index Stoichiometric and Reduced Surfaces of Ceria , 2012 .

[10]  J. Rufner,et al.  Surface Segregation in Chromium‐Doped Nanocrystalline Tin Dioxide Pigments , 2012 .

[11]  A. Navrotsky,et al.  Nanoceria – Energetics of Surfaces, Interfaces and Water Adsorption , 2011 .

[12]  H. Deng,et al.  Au–Ag Bimetallic Nanoparticles: Surface Segregation and Atomic-Scale Structure , 2011 .

[13]  P. Roussel,et al.  Quantification of MgO surface excess on the SnO2 nanoparticles and relationship with nanostability and growth , 2011 .

[14]  M. S. Hegde,et al.  Correlation of Oxygen Storage Capacity and Structural Distortion in Transition-Metal-, Noble-Metal-, and Rare-Earth-Ion-Substituted CeO2 from First Principles Calculation , 2010 .

[15]  R. Castro,et al.  Interface Energy Measurement of MgO and ZnO: Understanding the Thermodynamic Stability of Nanoparticles , 2010 .

[16]  Feng Liu,et al.  Influence of grain boundary energy on the grain size evolution in nanocrystalline materials , 2009 .

[17]  P. Roussel,et al.  Interface Excess and Polymorphic Stability of Nanosized Zirconia-Magnesia , 2008 .

[18]  R. B. Shaevich.  Measurement of the specific free surface energy of solids , 2007 .

[19]  E. Longo,et al.  Room temperature co-precipitation of nanocrystalline CeO2 and Ce0.8Gd0.2O1.9−δ powder , 2007 .

[20]  A. Navrotsky,et al.  Surface energy and thermodynamic stability of γ-alumina : Effect of dopants and water , 2006 .

[21]  A. Navrotsky,et al.  Direct measurements of water adsorption enthalpy on hafnia and zirconia , 2005 .

[22]  R. Birringer,et al.  Thermodynamic stabilization of nanocrystallinity , 2005, International Journal of Materials Research.

[23]  S. Seal,et al.  Size dependency variation in lattice parameter and valency states in nanocrystalline cerium oxide , 2005 .

[24]  R. Castro,et al.  Densification and electrical conductivity of fast fired manganese-doped ceria ceramics , 2005 .

[25]  Piotr Jasinski,et al.  Nanocrystalline undoped ceria oxygen sensor , 2003 .

[26]  A. Bhattacharya,et al.  Surface segregation of lanthanum and cerium ions in ceria/lanthana solid solutions: comparison between experimental results and a statistical–mechanical model , 2003 .

[27]  G. Rohrer,et al.  Grain boundary segregation in oxide ceramics , 2003 .

[28]  N. Browning,et al.  Segregation effects at grain boundaries in fluorite-structured ceramics , 2002 .

[29]  Philippe Knauth,et al.  Solute segregation, electrical properties and defect thermodynamics of nanocrystalline TiO2 and CeO2 , 2000 .

[30]  M. Inagaki,et al.  Preparation of monodispersed cerium(IV) oxide particles by thermal hydrolysis: influence of the presence of urea and Gd doping on their morphology and growth , 2000 .

[31]  M. Boaro,et al.  The utilization of ceria in industrial catalysis , 1999 .

[32]  I. Fragalà,et al.  Surface segregation of Sb in doped TiO2 rutile , 1995 .

[33]  Yanchun Zhou,et al.  Effect of solid solution additives on the sintering of ultra-fine CeO2 powders , 1995 .

[34]  S. C. Parker,et al.  Surface Segregation of Metal Ions in Cerium Dioxide , 1994 .

[35]  N. Ashcroft,et al.  Vegard's law. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[36]  W. C. Johnson.  Grain boundary segregation in ceramics , 1977 .

[37]  R. D. Shannon.  Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides , 1976 .

[38]  K. L. Kliewer.  Space Charge in Ionic Crystals. II. The Electron Affinity and Impurity Accumulation , 1965 .

[39]  J. Koehler,et al.  Space Charge in Ionic Crystals. I. General Approach with Application to NaCl , 1965 .

[40]  E. D. Hondros,et al.  The influence of phosphorus in dilute solid solution on the absolute surface and grain boundary energies of iron , 1965, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.