Ligand-Protected Au₅₅ with a Novel Structure and Remarkable CO₂ Electroreduction Performance

Area of Science:

• Nanomaterials Chemistry
• Catalysis
• Surface Science

Background:

• Gold nanoclusters are promising catalysts but their structural control remains challenging.
• Ligand choice significantly influences nanocluster formation and properties.
• Understanding structure-activity relationships is key for targeted applications.

Purpose of the Study:

• To synthesize and characterize a novel Au₅₅ nanocluster with a unique face-centered cubic kernel.
• To investigate the role of halide exclusion in nanocluster formation.
• To evaluate the catalytic performance of the synthesized Au₅₅ nanocluster for CO₂ reduction.

Main Methods:

• Direct reduction of gold-phosphine and gold-thiolate precursors.
• Single-crystal X-ray diffraction for structural elucidation.
• Electrochemical CO₂ reduction studies.

Main Results:

• A novel [Au₅₅ (p-MBT)₂₄ (Ph₃ P)₆ ](SbF₆ )₃ nanocluster with a face-centered cubic kernel was synthesized.
• Exclusion of chloride ions was critical for forming the Au₅₅ cluster, preventing the formation of rod-like Au₂₅ structures.
• The Au₅₅ nanocluster demonstrated high selectivity and activity for electrochemical CO₂ reduction to CO, achieving 94.1% Faradaic efficiency.

Conclusions:

• A new synthetic strategy for halide-free co-protected metal nanoclusters was established.
• The synthesized Au₅₅ nanocluster exhibits excellent catalytic performance for CO₂ conversion.
• This work provides insights into the structural control of gold nanoclusters for catalytic applications.