Double-well potential energy surface in the interaction between h-BN and Ni(111).

Ricardo Grau-Crespo,Francesc Viñes,Francesc Illas,Jorge Ontaneda

doi:10.1039/c8cp07880g

Abstract

Density functional theory calculations with non-local correlation functionals, properly accounting for dispersion forces, predict the presence of two minima in the interaction energy between h-BN and Ni(111). These can be described as a physisorbed state with no corrugation of the h-BN structure, and a chemisorbed state exhibiting noticeable corrugation and a shorter distance of h-BN to the metallic support. The latter corresponds indeed to the one reported in most experiments. The relative stability of the two minima depends on the specific density functional employed: of those investigated here only optB86b-vdW yields the correct order of stability. We also demonstrate that the effect of the metal support on the Raman frequency of the chemisorbed boron nitride monolayer cannot be reduced to the associated strain. This is important because the Raman frequency has been proposed as a signature to identify h-BN monolayers from multilayered samples. Our analysis shows that such signatures would be strongly dependent on the nature of the interaction between the support and h-BN.

Highlights

IntroductionIn the last two decades, the epitaxial growth of few-layers of hexagonal boron nitride (h-BN) on the (111) surface of face-centered cubic (fcc) metals such as Au, Cu, Rh, Pt, Pd, Ir, and Ni has been widely studied.[1,2,3,4,5,6,7,8,9] The motivation for these studies is that h-BN/metal interfaces have potential applications in areas such as protective coating, transparent membranes, or deep ultraviolet emitters.[10,11,12] Recent theoretical investigations have suggested that metal-supported nanosheets of h-BN might be active for both CO oxidation and oxygen reduction reaction (ORR).[13,14] the combined experimental and theoretical study of Uosaki et al demonstrated that h-BN supported on Au(111) surface has much better catalytic activity for ORR than a pure Au(111) electrode.[2]
For compatibility with our previous work where we investigated the origin of Raman signature in monolayers of hexagonal boron nitride (h-BN),[53] we will discuss below the addition of extra layers and the Raman frequencies of supported h-BN as calculated with the optB88-vdW, such that it facilitates the comparison between the free-standing and supported systems
We have shown that non-local correlation functionals predict the presence of two minima in the interaction energy between h-BN and Ni(111): one geometrically flat that can be identified as a physisorbed state and one with appreciable corrugation of the h-BN lattice and shorter interface distance, which can be identified as a chemisorbed state

Summary

Introduction

In the last two decades, the epitaxial growth of few-layers of hexagonal boron nitride (h-BN) on the (111) surface of face-centered cubic (fcc) metals such as Au, Cu, Rh, Pt, Pd, Ir, and Ni has been widely studied.[1,2,3,4,5,6,7,8,9] The motivation for these studies is that h-BN/metal interfaces have potential applications in areas such as protective coating, transparent membranes, or deep ultraviolet emitters.[10,11,12] Recent theoretical investigations have suggested that metal-supported nanosheets of h-BN might be active for both CO oxidation and oxygen reduction reaction (ORR).[13,14] the combined experimental and theoretical study of Uosaki et al demonstrated that h-BN supported on Au(111) surface has much better catalytic activity for ORR than a pure Au(111) electrode.[2]. The theoretical work of Gao and coworkers[15] showed that the energy barrier for the ORR depends on the type of defects, which play an important role at enhancing the stability the h-BN/metal heterostructures

Methods

Results

Conclusion