Reaction environment Optimization with Janus electrode in CO₂ electrochemical reduction to CO

Both metal and nonmetal electrodes normally exhibit a low CO partial current density (J_CO) of lower than 15 mA cm⁻² during CO₂ electrochemical reduction to CO in the aqueous phase, which is primarily attributed to the low solubility and mass transfer rate of CO₂. Modifying the catalyst surface with a hydrophobic substance is recognized as an effective strategy for addressing this challenge. However, the formation of a hydrophobic layer may evacuate the electrode surface from electrolyte. In this study, a one-step electrodeposition method was employed to prepare a polytetrafluoroethylene (PTFE)-doped Zn@ZnAg porous catalyst, and two doping approaches were investigated, which involved surface-layer doping and bulk-phase doping. Energy-dispersive spectrometer (EDS) mapping and X-ray diffractometer (XRD) analyses revealed that bulk-phase doping enabled uniform dispersion of PTFE over the pore walls of the ZnAg alloy. The results showed the Janus catalyst with a PTFE-doped side and an undoped one, achieved a remarkable J_CO of 34.19 mA cm⁻² with a CO Faradaic efficiency (FE_CO) of 90.75 % in 0.1 M KHCO₃ electrolyte at a potential of −2.6 V vs. SCE.