Spin-Modulated O₂ Adsorption on Surface-Constructed Metal-Organic Chains.

Area of Science:

• Surface Science
• Catalysis
• Quantum Chemistry

Background:

• Oxygen adsorption is critical for many catalytic reactions.
• The role of catalyst spin states in O2 adsorption mechanisms is not fully understood.
• Understanding these mechanisms requires atomic-scale insights.

Purpose of the Study:

• To investigate the atomic-scale mechanisms of oxygen adsorption on nickel centers with different spin states.
• To compare the O2 affinity of high-spin (NiH) and low-spin (NiL) nickel centers.
• To elucidate the influence of electronic structure on selective O2 binding.

Main Methods:

• Scanning tunneling microscopy/spectroscopy (STM/STS) for atomic-scale characterization.
• Atomic force microscopy (AFM) for comparative analysis.
• Density functional theory (DFT) calculations to model electronic interactions.

Main Results:

• Direct observation of preferential O2 adsorption at NiH compared to NiL centers.
• DFT confirms selectivity originates from distinct d-electron configurations and O2-Ni hybridization.
• O2 adsorption at NiH can induce a spin transition in NiL, potentially hindering binding.

Conclusions:

• Nickel spin state critically dictates O2 adsorption selectivity at the atomic level.
• Microscopic insights into spin-modulated O2 adsorption are provided.
• Findings advance the understanding of spin-dependent catalysis.