Electrocatalytic transformation of CO2 into C2 molecules
Electrocatalytic CO2 reduction (CO2R) enables the transformation of CO2 into valuable alcohols and hydrocarbons, such as ethylene, ethanol, and propanol, using renewable electricity. The reaction pathways differ - CO dimerization leads to ethylene, while asymmetric C–C coupling produces ethanol and other multi-carbon products.
Using Cu-Ag nanocrystal catalysts, the ELCAT group has achieved significant faradaic efficiency for ethanol production, with further improvements possible through the use of CO-generating co-catalysts and optimized catalyst structures. Key design factors such as morphology, electronic properties, wettability, and hydrogen-transfer behavior allow precise tuning of product selectivity while reducing unwanted H2 evolution.
At the system level, challenges remain - particularly low single-pass CO2 conversion efficiency (SPCE) and ethanol crossover through membranes. The e-SAF project explores advanced reactor configurations and cation-exchange membranes to overcome these issues, while also studying how temperature and mass transport affect performance.
Together, these innovations aim to make renewable, electricity-driven CO2 conversion a scalable route toward sustainable aviation fuels.
C2 to SAF
Ethanol and Ethylene Conversion to Jet-Fuel Precursors
Ethanol can be dehydrated to ethylene over solid acid catalysts, but mixed ethanol and ethylene feeds, such as those from electrochemical CO2 reduction, require optimized conditions for efficient dehydration–oligomerization.
Because acid catalysis alone struggles to activate ethylene, nickel-based catalysts are used to promote C–C coupling via organometallic pathways, enabling light olefin conversion into jet-fuel-range hydrocarbons. Combining Ni with acid sites enhances selectivity and chain growth.
Ni-containing porous materials—including silica–alumina, zeolites, and mesoporous aluminosilicates—are particularly effective. Mesoporous structures minimize pore blockage and coke formation, maintaining high conversion, selectivity, and stability. Alternatively, monofunctional acid catalysts could be paired with a propylene co-feed to bypass nickel, as acid catalysis favors secondary and tertiary carbocations.
To guide catalyst and process design, the e-SAF project applies Single-Event MicroKinetic (SEMK) modeling to capture fundamental reaction mechanisms and quantify synergistic effects in ethylene/propylene co-oligomerization, advancing the conversion of electrochemically derived intermediates into sustainable jet-fuel precursors.
