Structural Fusion-Induced Activity Suppression in Copper Nanoclusters for Electrocatalytic Nitrate Reduction.

Area of Science:

• Catalysis
• Nanomaterials Chemistry
• Surface Science

Background:

• Understanding structure-activity relationships is crucial in catalysis.
• Copper nanoclusters are promising electrocatalysts.
• Controlled synthesis of complex nanostructures remains a challenge.

Purpose of the Study:

• To investigate the impact of structural fusion on copper nanocluster catalytic behavior.
• To establish a platform for creating well-defined fused nanoclusters.
• To uncover structure-dependent anti-emergent phenomena in catalysis.

Main Methods:

• In situ generation and templating of C2 2- dianions using thiacalix[4]arene and alkynyl ligands.
• Controlled fusion of copper nanoclusters (Cu17) into superclusters (Cu40).
• Isolation of monomeric and fused copper clusters for comparative analysis.
• Electrocatalytic testing and in situ spectroscopic studies.
• Density Functional Theory (DFT) calculations.

Main Results:

• A novel C2 2- templated fusion pathway yielded well-defined Cu40 superclusters from Cu17 units.
• Fused Cu40 clusters exhibited suppressed nitrate reduction activity compared to monomeric Cu17 and Cu22 clusters.
• Cu17 demonstrated high ammonia selectivity (98.45%) and production rate (2.91 mol·h-1·g-1) for nitrate reduction.
• Fusion reduced catalytic activity by limiting surface accessibility and altering electronic properties of active sites.

Conclusions:

• Structural fusion in copper nanoclusters leads to an anti-emergent phenomenon of decreased catalytic activity.
• Optimized monomeric copper nanoclusters show superior performance for nitrate electroreduction to ammonia.
• Controlling nanocluster architecture is key to designing efficient catalysts.