Metal Active-Site Exposure via Ligand Engineering Boosts CO₂-to-Ethylene Conversion on Cu₁₈ Nanoclusters

Area of Science:

• Nanocatalysis
• Materials Science
• Electrochemistry

Background:

• Tuning surface and interface properties of isostructural nano-catalysts is crucial for understanding structure-activity relationships.
• Developing atomically precise nano-catalysts with controllable properties presents a significant challenge.

Purpose of the Study:

• To synthesize isostructural copper hydride nanoclusters with tunable surface properties using ligand engineering.
• To investigate the structure-activity relationships of these nanoclusters in CO2 electroreduction.

Main Methods:

• Synthesis of two atomically precise, isostructural Cu hydride nanoclusters: [Cu18H17(EtPP)10]+ (Cu18-1) and [Cu18H17(TPP)10]+ (Cu18-2) via ligand engineering.
• Electrochemical evaluation of CO2 electroreduction reaction (CO2ERR).
• Post-reaction mass spectrometry, theoretical calculations, and electrochemically active surface area measurements to elucidate the reaction mechanism.

Main Results:

• Cu18-1 demonstrated significantly higher C2H4 selectivity (70.59%) and current density (-2.99 A·m-2) compared to Cu18-2 in CO2 electroreduction.
• The enhanced performance of Cu18-1 is attributed to weaker intramolecular interactions, facilitating ligand stripping and exposing more active metal sites for C-C coupling.
• Ligand engineering successfully modulated surface/interface interactions, impacting catalytic activity.

Conclusions:

• Ligand engineering is an effective strategy for tuning the performance of isostructural nano-catalysts.
• Weaker intramolecular interactions in Cu18-1 promote active site exposure and enhance CO2 electroreduction to C2H4.
• This study provides insights into designing metal-organic catalysts by regulating intramolecular interactions for improved catalytic efficiency.