Selectivity of a Copper Oxide CO₂ Reduction Electrocatalyst Shifted by a Bioinspired pH-Sensitive Polymer

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Copper oxide (CuO) is a promising electrocatalyst for CO2 reduction.
• Improving selectivity and efficiency in CO2 electroreduction remains a challenge.
• Controlling the catalyst's microenvironment is crucial for reaction selectivity.

Purpose of the Study:

• To develop a bioinspired polymeric membrane to enhance CuO electrocatalyst selectivity for CO2 reduction.
• To investigate the mechanism by which the membrane influences the reaction pathway.
• To favor CO2 reduction over the hydrogen evolution reaction (HER).

Main Methods:

• Deposition of a block copolymer membrane (PMMA-b-P4VP) on CuO thin films using wet deposition.
• Characterization of membrane self-assembly and porous structure.
• Electrochemical evaluation of the modified CuO catalyst under CO2 reduction conditions.

Main Results:

• The membrane self-assembles into a porous structure, inducing a Cassie-Baxter wetting transition above neutral pH.
• The hydrophobic membrane surface repels water, creating a CO2-rich microenvironment at the catalyst surface.
• The CO2 reduction reaction selectivity was kinetically favored over HER.

Conclusions:

• Bioinspired membranes can effectively tune catalyst selectivity in electrochemical reactions.
• Controlling catalyst hydrophobicity and microenvironment is a viable strategy to enhance CO2 electroreduction.
• This approach offers a pathway to improve efficiency and selectivity for CO2 conversion technologies.