A High-Nuclearity Copper Sulfide Nanocluster [S-Cu₅₀] Featuring a Double-Shell Structure Configuration with...

Area of Science:

• Materials Science
• Nanotechnology
• Inorganic Chemistry

Background:

• Atomically precise nanoclusters (NCs) are crucial for advanced applications.
• Synthesizing binary semiconductor nanoclusters (BS-NCs) demands precise control over reaction kinetics to ensure single-phase formation.
• Previous methods often result in multiple phases, complicating NC synthesis.

Purpose of the Study:

• To develop a reliable method for synthesizing atomically precise copper sulfide nanoclusters.
• To characterize the structure, electronic properties, and potential applications of a novel copper sulfide nanocluster.
• To overcome challenges in controlling phase formation during BS-NC synthesis.

Main Methods:

• An acid-assisted thiolate dissociation approach was employed.
• Cleavage of S-C bonds in Cu-S-R precursors facilitated [Cu-S-Cu] skeleton formation.
• Single-crystal X-ray diffraction was used for atomic structure determination.

Main Results:

• Successfully synthesized a high-nuclearity copper sulfide nanocluster, Cu50S12(SC(CH3)3)20(CF3COO)12 ([S-Cu50]), in high yield.
• Discovered a unique double-shell structure ([Cu14S12]@[Cu36S20]) with an unprecedented rhombic dodecahedron geometry in the inner core.
• Confirmed the presence of mixed Cu(II)/Cu(I) valences, establishing [S-Cu50] as the first such atomically precise copper sulfide NC.
• Characterized the electronic structure using various optical and theoretical methods.
• Demonstrated air stability and electrocatalytic activity in oxygen reduction reaction (ORR) via a four-electron pathway.

Conclusions:

• The developed acid-assisted method enables high-yield synthesis of complex, atomically precise BS-NCs.
• [S-Cu50] represents a significant advancement in NC design, featuring a novel structure and mixed valency.
• The unique properties of [S-Cu50] suggest potential applications in catalysis, particularly in ORR.