Boron atom incorporation into metal nanoparticles

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Boron incorporation into transition metals (TMs) like palladium (Pd) and platinum (Pt) unintentionally occurs during synthesis.
• Surface boron significantly impacts the catalytic performance of TMs.

Purpose of the Study:

• To investigate the thermodynamics and kinetics of boron incorporation into various transition metal nanoparticles (NPs) and surfaces.
• To understand how boron affects the electronic structure and catalytic activity of these metals.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Investigated boron incorporation into ~1.5 nm nanoparticles and extended (111) surfaces.
• Studied face-centered cubic (fcc) metals: Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, and Al.

Main Results:

• Boron is thermodynamically stable in subsurface interstitial sites on surfaces and NPs of Rh, Pt, and Pd.
• Metal nanoparticles (NPs) stabilize boron in surface metal coordination sites, especially in Rh, Ir, and Ni NPs.
• Low energy barriers (<0.5 eV) for boron migration to subsurface sites in NPs and <0.2 eV for incorporation into surface sites were observed.
• Boron incorporation shifts the d-band center of adjacent metal atoms, impacting catalytic activity.

Conclusions:

• Boron's incorporation into transition metal surfaces and nanoparticles is thermodynamically favorable and kinetically accessible.
• Boron significantly modifies the electronic properties of transition metals, particularly their d-band center.
• These findings highlight boron's potential to tune the catalytic activity of transition metals for various applications.