Optimizing Hydrophobicity of Cu@Zn Foam Catalysts for Efficient CO2 Electroreduction in a Microchannel Reactor

CO2 electrochemical reduction is a promising way to convert CO2 to valuable fuels and chemicals. This study presents a porous Cu@Zn foam catalyst with a tailored hydrophobic surface for enhanced CO2 reduction. The catalyst is synthesized via a modified dynamic hydrogen bubble template method, incorporating polytetrafluoroethylene (PTFE) during electrodeposition to control wettability. This strategy creates a hydrophobic microenvironment that significantly increases the three-phase (gas–liquid–solid) contact area, promoting CO2 mass transfer and suppressing the competing hydrogen evolution reaction. The optimized Cu@Zn-8PTFE catalyst achieves a CO Faraday efficiency (FECO) of 87.53% at −35 mA cm−2, a 40% improvement over the unmodified Cu@Zn. Furthermore, it also exhibits excellent stability, maintaining FECO > 90% for 64 h at −15 mA cm−2. While hydrophobic modification is beneficial, excess PTFE loading reduces performance by covering active sites and diminishing the three-phase interface. This work highlights the importance of controlling catalyst wettability to optimize the three-phase interface for enhanced CO2 electroreduction.