Polymer-Halogen Pockets Steering ^*CO Adsorption Configurations for Highly Selective CO₂ Electroreduction.

Area of Science:

• Catalysis
• Electrochemistry
• Materials Science

Background:

• Selective electroreduction of carbon dioxide (CO2R) to C2 products is challenging due to the need for precise control over CO intermediates.
• Existing catalysts often lack the tunability to direct CO2R towards specific products like ethylene or ethanol.

Purpose of the Study:

• To develop a "polymer-halogen" pocketed copper catalyst for tunable CO2R.
• To demonstrate the modulation of CO adsorption configurations by controlling iodide ion concentration.
• To achieve selective production of ethylene and ethanol from CO2.

Main Methods:

• Fabrication of a perfluorosulfonic acid (PFSA)-modified CuI catalyst with in-situ generated and confined iodide ions.
• Tuning the PFSA shell thickness to control iodide concentration within the "polymer-halogen" pockets.
• Utilizing surface-enhanced in-situ Raman spectroscopy to analyze *CO intermediate adsorption on Cu surfaces.

Main Results:

• The "polymer-halogen" pocket catalyst allows continuous modulation of *CO adsorption configurations on Cu.
• Increased iodide concentration favors *CO adsorption at low-coordination Cu sites, promoting ethylene formation.
• *CO at medium-coordinated sites favors ethanol production, enabling tunable ethylene-to-ethanol ratios from 0.65 to 3.96.
• Achieved peak Faradaic efficiencies of 60.3% for ethylene and 48.3% for ethanol.

Conclusions:

• The "polymer-halogen" pocket strategy offers precise control over CO2R selectivity by tuning *CO intermediates.
• This approach provides a pathway for efficient and selective electrocatalytic conversion of CO2 to valuable C2 products.
• The catalyst design demonstrates significant potential for industrial applications in CO2 utilization.