Microfluidic System for CO2 Reduction to Hydrocarbons in Microgravity

In the combined Phase I and Phase II programs Faraday and our MIT collaborators will demonstrate the feasibility of low-cost fabrication of high-efficiency, microchannel-plate reactors for the electrocatalytic reduction of CO2 to CH4. The proposed concept is founded on FARADAYIC® Through-Mask Etching of metallic (e.g., stainless steel and titanium) substrates to form suitable microchannel electrodes, and on pulse-reverse FARADAYIC® Electrodeposition of copper for uniform coating of the cathode surfaces. The electrocatalytic efficiency of the copper layer will be enhanced through the use of a literature-reported oxide-reduction process. Inclusion of a suitably large density of channels should result in substantial active area in a compact form factor, while entirely avoiding the complications of packed-bed type reactors. Faraday plans to focus development toward the ultimate use of room-temperature ionic liquids (ILs), as they afford such advantages as negligible evaporative loss, generally high CO2 solubility and low CH4 solubility, and a broad potential window of electrochemical inertness. The particular challenge of gas-liquid separations in microgravity, where buoyant effects cannot be exploited, will be addressed through a novel centripetal application of an established spiral-channel microfluidic concept. The envisioned system described in this proposal consists of three distinct unit operations: (1) an absorber which "getters" gaseous CO2 from the atmosphere using a wet room temperature IL-based electrolyte, (2) a microfluidic electroreactor which efficiently converts the CO2 to CH4 with oxygen being generated as useful by-product, and (3) a spiral-channel gas-liquid separator to remove the CH4 and O2 from the IL stream which is recycled to the absorber.