Systematic Thiol Decoration in a Redox-Active UiO-66-(SH)₂ Metal-Organic Framework: A Case Study under Oxidative and...

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Thiolated metal-organic frameworks (MOFs) exhibit limited practical use due to poor crystallinity and stability.
• Developing robust thiolated MOFs is crucial for advanced applications.

Purpose of the Study:

• To synthesize stable mixed-linker UiO-66-(SH)2 MOFs (ML-U66SX) via a one-pot solvothermal method.
• To investigate the impact of linker ratios and modulator concentration on MOF properties.
• To evaluate the stability of ML-U66SX under reductive and oxidative conditions and its performance as a catalyst support.

Main Methods:

• One-pot solvothermal synthesis with varying ratios of 2,5-dimercaptoterephthalic acid (DMBD) and 1,4-benzenedicarboxylic acid.
• Characterization of crystallinity, defectiveness, porosity, and particle size.
• Stability testing under reductive and oxidative chemical environments.
• Evaluation as sacrificial catalyst supports for gold-catalyzed 4-nitrophenol hydrogenation.

Main Results:

• Stable ML-U66SX MOFs were successfully synthesized, with properties tunable by linker ratios.
• Framework collapse and gold nanocluster release decreased with increasing DMBD proportion, reducing reaction rates by 59%.
• UiO-66-(SH)2 MOF showed immediate structural breakdown post-oxidation, unlike mixed-linker variants, but its surface area increased to 739 m²/g.

Conclusions:

• A mixed-linker strategy effectively stabilizes UiO-66-(SH)2 MOFs under harsh chemical conditions.
• Controlled thiol decoration is key to enhancing MOF stability and catalytic applications.
• This approach offers a pathway to design robust MOFs for demanding chemical environments.