Ultrastable Anti-Acid "Shield" in Layered Silver Coordination Polymers.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Surface Chemistry

Background:

• Noble-metal materials often lack chemical stability, particularly in acidic environments.
• Understanding atomic-level anticorrosion mechanisms is crucial for enhancing noble-metal particle stability.
• Two-dimensional (2D) noble-metal coordination polymers (CPs) serve as ideal models for interfacial studies.

Purpose of the Study:

• To design an effective strategy for enhancing the stability of noble-metal particles.
• To investigate the surface anticorrosion mechanism of noble-metal materials at the atomic level.
• To utilize 2D CPs as model systems for interfacial stability studies.

Main Methods:

• Isolation of two Ag-based 2D CPs, {Ag14(TBI)12X2}n (S-X), using 2-thiobenzimidazole (TBI).
• Systematic characterization of the synthesized CPs.
• Density Functional Theory (DFT) analyses to elucidate the stability mechanism.

Main Results:

• The synthesized Ag-based 2D CPs (S-X) exhibited excellent chemical stability.
• Stability was demonstrated upon immersion in various solvents, boiling water, hydrogen peroxide, concentrated acid (12 M HCl), and concentrated alkali (19 M NaOH).
• DFT analyses confirmed the protective role of the hydrophobic organic shell and a dynamic proton buffer layer.

Conclusions:

• The superior stability of the 2D Ag-CPs is attributed to a dual protective shield.
• This dual shield comprises a hydrophobic organic shell and a dynamic proton buffer layer.
• The findings provide insights into designing stable noble-metal materials for demanding applications.