Density Functional Theory Study of Ni Clusters Supported on the ZrO2(111) Surface

A Cadi‐Essadek,A Roldan,N H De Leeuw

doi:10.1002/fuce.201600044

A Cadi‐Essadek, A Roldan + Show 1 more

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https://doi.org/10.1002/fuce.201600044

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Abstract

AbstractThe nickel/zirconia (Ni/ZrO2) interface plays a key role in the performance of the anode of solid oxide fuel cells (SOFC) and it is therefore important to understand the interaction between nickel nanoparticles and the ZrO2 surface. Here, we have described the interaction of five Nin (n = 1–5) clusters with the (111) surface of cubic zirconia, c‐ZrO2(111), using spin polarized density functional theory (DFT) calculations with inclusion of long‐range dispersion forces. We have systematically evaluated the geometric and electronic structure of different cluster configurations and sizes and shown how the clusters interact with the oxygen and zirconium surface atoms. The cluster‐surface interaction is characterized by a charge transfer from the Ni clusters to the surface. From calculations of the hopping rate and clustering energies, we have demonstrated that Ni atoms prefer to aggregate rather than wet the surface and we would therefore suggest that modifications in the synthesis could be needed to modify the coalescence of the supported metal particles of this catalytic system.

Highlights

Metal-oxide interfaces are efficient catalytic systems used in many industrial processes, e.g., microelectronics, sensors and solid oxide fuel cells (SOFC) [1,2,3,4,5,6,7], the growing interest in these cermets over the past decade
Nickel is the metal primarily used in SOFC, and it is well known that the performance of the Ni/ytrria-stabilized zirconia (YSZ) cermet depends on the microstructure and the distribution of the Ni and YSZ phases in the cermet [14]
Nin (n = 1–5) clusters with the ZrO2(111) surface, where we have shown that the clustering energy decreases with increasing Ni cluster size

Summary

Introduction

Metal-oxide interfaces are efficient catalytic systems used in many industrial processes, e.g., microelectronics, sensors and solid oxide fuel cells (SOFC) [1,2,3,4,5,6,7], the growing interest in these cermets over the past decade. Methods based on the density functional theory (DFT) are suitable for the description of metal-oxide interfaces [15], but it is a time-consuming method and in this work we have focused on the study of the adsorption of small clusters (Ni1-5) on the ZrO2(111) surface to provide fundamental insight into the Ni/ZrO2(111) interaction. Luches et al [18] characterized by STM and XPS measurements the nucleation and growth of Ag nanoparticles on CeO2(111) They have complemented their experimental results with DFT calculations, where they showed charge transfer from the Ag clusters to the ceria surface. Hahn et al [19] used DFT to study the adsorption of Ni clusters on top of CeO2(111) and showed that the metal cluster is stabilized as the cluster size increases (up to ten atoms). We have calculated the hopping rate to gain insight into the diffusion of Ni atoms on the c-ZrO2(111) surface

Models and Computational Methods

Results and Discussion

Structural Analysis of the Ni-surface Interface

Conclusions