Adsorption of transition metal adatoms on h-BN/Rh(111): Implications for nanocluster self-assembly

• Published in: Catalysis today 2017-02, Vol.280 (P2), p.220-231
• Main Authors: McKee, William C., Patterson, Matthew C., Frick, Jordan R., Sprunger, Phillip T., Xu, Ye
• Format: Article
• Language: English
• Subjects: DFT; Diffusion; h-BN/Rh; Hexagonal boron nitride; Nanocatalyst; Nucleation
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2016.09.030

[Display omitted] •Nucleation and growth of size-limited, monodisperse metal nanoparticles on h-BN/Rh(111) is investigated via DFT calculations.•Au and Pt adatoms have high barriers (>1.2eV) for diffusing across the nanomesh surface, whereas Ag, Pd, Cu, and Ni do not.•STM verifies that Au and Pt form monodisperse nanoparticles on h-BN/Rh(111) whereas Ag fails to do so, consistent with DFT. The hexagonal boron nitride (h-BN) nanomesh is a promising 2D material for driving the self-assembly of metal nanoparticles with potential catalytic applications. Herein the adsorption of Au, Pt, Ag, Pd, Cu, and Ni adatoms on h-BN/Rh(111) is investigated using density functional theory (DFT) calculations to determine the ability of this pore-wire structure to facilitate the formation of size-limited, monodisperse metal nanoparticles. While all six metal atoms exhibit covalent coupling and negative charging following their adsorption in the pore region, only Au and Pt have sufficiently large barriers (>1.2eV) to prevent pore-to-pore diffusion at room temperature. In contrast, Ag and Cu have pore-to-pore diffusion barriers of only ∼0.5eV, while Pd and Ni show no special affinity for any specific region of the nanomesh. For verification, we have imaged Au, Pt, and Ag on h-BN/Rh(111) at room temperature and submonolayer depositions using STM. Au and Pt form numerous small nanoparticles confined to the pore regions, whereas Ag only forms a few large particles. The difference is fully consistent with the DFT predictions, indicating that our approach has qualitatively predictive power for nanoparticle nucleation and growth behavior on the h-BN/Rh(111) nanomesh.