Capturing carbon dioxide is one of the great ways to reduce the CO2 in the atmosphere while providing valuable renewable energy. Opus 12 is a Cyclotron Road startup using a membrane-electrode assembly (MEA) design. LBNL helped Opus 12 optimize its MEA design in this project through materials characterization and in situ studies. The finding of this project was used to develop a set of ideas for their MEA improvement under different operating conditions.

Electrochemical CO2 reduction (ECR) promises the replacement of fossil fuels as the source of feedstock chemicals and seasonal storage of renewable energy. While much progress has been made in catalyst development and electrochemical reactor design, few studies have addressed the effect of catalyst integration on device performance. Using a microfluidic gas diffusion electrolyzer, we systematically studied the effect of thickness and the morphology of electron beam (EB) and magnetron-sputtered (MS) Cu catalyst coatings on ECR performance. We observed that EB-Cu outperforms MS-Cu in current density, selectivity, and energy efficiency, with 400 nm thick catalyst coatings performing the best. The superior performance of EB-Cu catalysts is assigned to their faceted surface morphology and sharper Cu/gas diffusion layer interface, which increases their hydrophobicity. Tests in a large-scale zero-gap electrolyzer yielded similar product selectivity distributions with an ethylene Faradaic efficiency of 39% at 200 mA/cm2, demonstrating the scalability for industrial ECR applications.

Cu-based catalysts currently offer the most promising route to actively and selectively produce value-added chemicals via electrochemical reduction of CO2 (eCO2R); yet further improvements are required for their wide-scale deployment in carbon mitigation efforts. Here, we systematically investigate a family of dilute Cu-based alloys to explore their viability as active and selective catalysts for eCO2R through a combined theoretical-experimental approach. Using a quantum-classical modeling approach that accounts for dynamic solvation effects, we assess the stability and activity of model single-atom catalysts under eCO2R conditions. Our calculations identify that the presence of eCO2R intermediates, such as CO*, H*, and OH*, may dynamically influence the local catalyst surface composition. Additionally, we identify through binding energy descriptors of the CO*, CHO*, and OCCO* dimer intermediates that certain elements, such as group 13 elements (B, Al, and Ga), enhance the selectivity of C2+ species relative to pure Cu by facilitating CO dimerization. The theoretical work is corroborated by preliminary testing of eCO2R activity and selectivity of candidate dilute Cu-based alloy catalyst films prepared by electron beam evaporation in a zero-gap gas diffusion electrode-based reactor. Of all studied alloys, dilute CuAl was found to be the most active and selective toward C2+ products like ethylene, consistent with the theoretical predictions. We attribute the improved performance of dilute CuAl alloys to more favorable dimerization reaction energetics of bound CO species relative to that on pure Cu. In a broader context, the results presented here demonstrate the power of our simulation framework in terms of rational catalyst design.

Opus 12 is developing an electrochemical process to convert CO2 into chemicals and fuels. Using only CO2, water, and electricity as inputs, the electrochemical reduction of CO2 could form the basis of an artificial carbon cycle that replaces a wide range of products that are currently derived from fossil fuel resources. We have developed a prototype that demonstrates high selectivity and current density for CO2 conversion to CO, which can be used to make high-value products including methanol, acetic acid, polymers, and pharmaceuticals.

Determining ideal pacing rates to meet physiological needs and optimizing programming to prevent unnecessary right ventricular pacing in dogs requires an understanding of heart rate profiles and applicable pacing technology. The heart rate and rhythm of the dog is complex necessitating investigation of rate requirements of activity and circadian influences. Overlaying this information are a multiplicity of other factors such as age, breed, temperament, cardiovascular disease and underlining rhythm disorders that contribute to the difficulty in making general conclusions. However, all such information permits better implementation of programming options with the goal of better outcomes. In this review (Part 1 of a two-part review) instantaneous heart rate, rolling average heart rate, simple average heart rate, heart rate tachograms, RR interval tachograms (2D, 3D and dynamic), and Poincaré plots (2D, 3D and dynamic) are discussed as they apply to decisions in the determination and examination of pacing rates for dogs programmed in the VVI pacing mode (Ventricular paced, Ventricular sensed, Inhibited pacing). The applicable pacing operations available for three pacemaker companies are reviewed (Abbott, Biotronik/Dextronix, and Medtronic). The programmable options considered include: slowest pacing rate without additional features to extend the pacing interval, sleep/rest rate preferences, hysteresis to lengthen pacing interval following intrinsic beats, and intermittent increases in pacing following abrupt loss of intrinsic rhythm. Recommendations are suggested for follow-up of individual dogs with examination of pacing statistics and Holter monitoring.

Electrochemical CO2 reduction (ECR) is a promising technology to close the anthropic CO2 circle using renewable energy to achieve carbon neutrality. Future commercialization of ECR will require the development of new catalyst synthesis routes that will allow significant upscaling of catalyst production from current research-level milligram quantities to the kilogram scale and beyond while maintaining the activity and selectivity demonstrated at the research level. In this work, we report on generating and testing submicron-sized nanoporous copper (npCu) particles by using a scalable approach consisting of ball milling brittle Cu-based intermetallics followed by dealloying to add nanoporosity for high surface area. The resulting npCu particles have been tested in an industry-relevant large area (25 cm2) electrolyzer platform and showed Faraday efficiencies (FE) for ethylene up to 34 % at current densities of 75−100 mA/cm2 while keeping FE for hydrogen less than 30 %. Our results demonstrate that a combination of ball milling and dealloying is a promising approach to generate large quantities of high activity and high surface area npCu particles for ECR at an industry-relevant scale.

We report on integrating ultrathin monolithic nanoporous gold (npAu) catalyst coatings for CO2 reduction in a large electrode area (25 cm2) electrochemical membrane reactor with gas diffusion electrodes at 100 mA/cm2. The CO Faraday efficiency increases with increasing thickness, from 65% to 75% and 80% for 1, 5, and 10 layers of npAu leaves where each npAu leaf layer is 100 nm thick. For the one npAu leaf layer configuration, this corresponds to an extremely high CO current density of 955 A/g gold thus demonstrating the potential for commercial applications.

Can a solid foundation for the future adaptation of solar fuels be built today? Component technologies developed to efficiently generate fuel from sunlight are finding innovative pathways to commercialization in established markets.

AbstractThe activity and selectivity for CO2/CO reduction over Cu electrodes is strongly dependent on the local surface structure of the catalyst and the pH of the electrolyte. Here we investigate a unique, Cu nanocube surface (CuCube) as a CO reduction electrode under neutral and basic pH by using online electrochemical mass spectroscopy (OLEMS) to determine the onset potentials and relative intensities of methane and ethylene production. To relate the unique selectivity to the surface structure, the CuCube surface reactivity is compared to polycrystalline Cu and three single crystals under the same reaction conditions. We find that the high selectivity for ethylene over the CuCube surface is most comparable to the Cu(1 0 0) surface, which has a cubic unit cell. However, the suppression of methane production over CuCube is unique to that particular surface. A basic pH is shown to enhance ethylene selectivity on all surfaces, and again the CuCube surface is unique.