Coordination-Engineered Interfacial Pathway Partitioning for Electrocatalytic CO₂ Conversion and Downstream Upgrading

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Electrochemical CO2 reduction (eCO2RR) shows promise for producing valuable carbon products.
• Understanding the interfacial factors governing pathway selection in eCO2RR is crucial for catalyst design.
• Current eCO2RR systems often lack control over product selectivity and downstream processing.

Purpose of the Study:

• To investigate the role of catalyst coordination environment in controlling eCO2RR pathway selectivity.
• To elucidate the interfacial mechanisms dictating the formation of formate versus CO.
• To demonstrate integrated eCO2RR with efficient downstream product upgrading.

Main Methods:

• Synthesis and characterization of coordination-environment-tunable Cu-Sn catalysts.
• In situ spectroscopy (e.g., FTIR, Raman) to study adsorbed intermediates and interfacial water.
• H/D kinetic isotope analysis and in situ electrochemical impedance spectroscopy-distribution of relaxation times (EIS-DRT) to probe reaction kinetics.
• Density functional theory (DFT) calculations to understand energetic origins of pathway bifurcation.

Main Results:

• Cu-Sn catalysts effectively partitioned CO2 electrosynthesis between Sn-centered (formate) and Cu-centered (CO) pathways.
• Coordination environment influenced adsorbed intermediates and interfacial water structures, correlating with pathway selection.
• DFT calculations revealed energetic differences in adsorption and interfacial energetics based on coordination.
• Downstream electrodialysis achieved 98.1% HCOOK-to-HCOOH conversion; CO2-NH3 route yielded formamide with 45.2% FE.

Conclusions:

• Catalyst coordination engineering is a viable strategy for controlling interfacial partitioning in eCO2RR.
• This approach enables selective synthesis of downstream-compatible carbon products like formate and formamide.
• Integrated eCO2RR with downstream upgrading offers a pathway for efficient carbon utilization.