Customizing Ferrocene Units into Atomically Precise Cu₁₁ Clusters for Boosting Oxygen Reduction to H₂O₂

Area of Science:

• Catalysis
• Materials Science
• Organometallic Chemistry

Background:

• Atomically precise metal clusters offer tunable properties for catalysis.
• Integrating organometallic compounds into clusters can enhance catalytic activity and elucidate structure-activity relationships.
• The two-electron oxygen reduction reaction (2e⁻ ORR) is crucial for producing hydrogen peroxide (H₂O₂).

Purpose of the Study:

• To synthesize novel atomically precise copper clusters incorporating ferrocene units.
• To investigate the catalytic performance of these clusters in the 2e⁻ ORR.
• To understand the structure-activity relationships governing H₂O₂ production.

Main Methods:

• A straightforward and scalable synthesis of Cu₁₁ clusters using DPPF (1,1-bis(diphenylphosphino)ferrocene) and cyclohexanethiol.
• Characterization using operando infrared spectroscopy and X-ray absorption fine structure spectroscopy.
• Density Functional Theory (DFT) simulations to analyze reaction mechanisms.

Main Results:

• Successful synthesis of Cu₁₁-DPPF, Cu₁₁-DPPM, and Cu₁₁-DPPE clusters with a cloverleaf-like structure.
• Cu₁₁-DPPF exhibited exceptional catalytic performance in 2e⁻ ORR, achieving >97.5% H₂O₂ selectivity.
• DFT and spectroscopic studies revealed that ferrocene units optimize OOH* adsorption for efficient H₂O₂ generation.
• Demonstrated efficacy in Fenton-like reactions for pollutant degradation using in situ H₂O₂.

Conclusions:

• Atomically precise copper clusters functionalized with ferrocene are effective catalysts for 2e⁻ ORR.
• The ferrocene moiety plays a key role in enhancing H₂O₂ selectivity through electronic effects.
• These hybrid catalysts offer a promising platform for selective H₂O₂ production and related applications.