CO2 Reduction to Hydrocarbons via Copper Gas-Diffusion Electrocatalysts
- Faraday Technology, Inc., Clayton, OH (United States)
Since the 1870’s, there have been many attempts to find efficient approaches to reduce CO2 to various organic compounds due to the industrial need for a carbon source and the large amounts of CO2 generated by human activities. However, major scientific challenges still exist to realize development of an efficient, inexpensive, and durable catalytic system. Modern carbon emission mitigation efforts in the interim have focused on carbon capture and sequestration (CCS), but despite the remaining challenges in developing CO2 conversion technologies, the need is clear that in order to reduce risk and offset the cost of CCS, development of adjunct CO2 utilization/conversion technologies to generate value-added products will be required. One promising approach for CO2 conversion is electrocatalytic reduction, which can be achieved on various cathode materials. Ethylene is of interest as a CO22 to a product such as ethylene, however, require the development of efficient, selective processing apparatus and conditions. While a variety of materials have been shown to enable selective reduction of CO2, copper is the only single-element catalyst known to produce higher hydrocarbons, including ethylene. Advances in Cu catalyst development have been translated into flow reactors that demonstrate moderate conversion efficiencies and relatively high current densities providing that a gas diffusion electrode (GDE) was used to enable a gaseous CO2 feed. However, literature reports indicate that at higher catalyst loadings desirable for high production rates, efficiencies drop and undesirable side product formation increases as mass transport limitations leads to reactant starvation. Thus, a key technical challenge is the development of Cu-coated gas diffusion electrodes that simultaneously enable high currents (high product yields) and high mass transfer rates (high efficiencies). Meeting both of these performance metrics requires a Cu catalyst layer with a high surface area a porous structure. In this program, Faraday and our MIT collaborator, Prof. Fikile Brushett, have exploited the demonstrated capability of pulsed FARADAYIC® Electro¬Deposition to fabricate highly textured, nanostructured Cu catalyst layers onto GDLs to serve as high performance cathodes within flow reactors for the conversion of CO2 to ethylene and other value-added products. In this Phase I SBIR program, copper GDE electrocatalysts were prepared by pulsed FARADAYIC® ElectroCatalyzation methods and tested using a custom-designed flow reactor built in Prof. Brushett’s laboratory. The use of FARADAYIC® waveforms was found to be crucial in order to obtain well-adhered, high-performance catalysts. The best catalysts fabricated in the program supported total current densities above 140 mA cm 2, comparable to some of the highest values reported in the literature to date, at ethylene selectivities competitive with those literature results (≈ 40%). Preliminary economic/scale-up analysis of FARADAYIC® ECHANGE®, an established plate-and-frame technology developed by Faraday, as a form factor for the Cu GDE technology under development, indicates that the capital costs for a full-scale CO2 conversion system are reasonable in the context of the NETL Case B12B baseline facility. Continuation of the Phase I work into Phase II will focus on optimization of the Cu GDE fabrication protocol (GDL substrate composition, ionomer pretreatment, plating electrolyte composition, FARADAYIC® ElectroDeposition waveform, etc.) and also development of optimized gas and/or liquid flow fields for the flow reactor at both a benchtop and an alpha demonstration scale. In particular, Faraday aims to reduce the deposited copper particle size by at least an order of magnitude, ideally below 10 nm, which should enhance both the available catalytic surface area (and thus the feasible geometric current density) and the durability and ethylene selectivity of the catalyst. The robustness of the optimized preparation protocol will be established through suitable replicate and long-duration (durability) studies, and the optimal operating conditions will be identified.
- Research Organization:
- Faraday Technology, Inc., Clayton, OH (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- SC0017199
- OSTI ID:
- 1410978
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- DOE-FTI-0017199; Faraday-2119
- Country of Publication:
- United States
- Language:
- English
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