Electrochemical CO2 reduction to CO in a zero-gap anion exchange membrane cell for a novel sustainable aviation process

The electrochemical reduction of carbon dioxide (CO₂RR) has emerged as a promising route for the sustainable production of carbon monoxide (CO) and other carbon-based intermediates, serving as feedstock for synthetic fuel synthesis within Power-to-X schemes. This approach directly couples renewable electricity with CO₂ utilization, offering a pathway to close the carbon cycle and mitigate greenhouse gas emissions.

This work forms part of a broader research initiative (4AirCRAFT H2020 project GA 101022633) aimed at developing novel routes for the production of sustainable aviation fuels (SAFs), addressing one of the most challenging sectors to decarbonize due to its high energy density requirements and limited alternative technologies. Within this framework, the selective electrochemical conversion of CO₂ to CO represents a crucial intermediate step toward the synthesis of hydrocarbons compatible with current aviation fuel specifications.

In this work, a planar zero-gap electrochemical cell equipped with an anion-exchange membrane and an active geometric area of 15 cm² was developed and tested for the selective reduction of CO₂ to CO under mild operating conditions. The cell configuration employed a Ni- based anode and a ZnAl electrocatalyst deposited on carbon substrate cathode, operating in 0.1M KHCO₃ electrolyte. Systematic chronopotentiometric (CP) experiments were conducted to assess the effect of applied potential and current density on Faradaic efficiency (FE), and stability.

Electrochemical impedance spectroscopy (EIS) measurements were performed to evaluate charge transfer resistance and ion transport properties across the electrode-electrolyte interface, providing insight into limitations of the system. The combined analysis enabled the identification of optimal operating conditions that maximize CO selectivity while minimizing energy consumption and performance degradation.