Abstract The electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach for reducing atmospheric carbon dioxide (CO2) emissions, allowing harmful CO2to be converted into more valuable carbon‐based products. On one hand, single carbon (C1) products have been obtained with high efficiency and show great promise for industrial CO2capture. However, multi‐carbon (C2+) products possess high market value and have demonstrated significant promise as potential products for CO2RR. Due to CO2RR's multiple pathways with similar equilibrium potentials, the extended reaction mechanisms necessary to form C2+products continue to reduce the overall selectivity of CO2‐to‐C2+electroconversion. Meanwhile, CO2RR as a whole faces many challenges relating to system optimization, owing to an intolerance for low surface pH, systemic stability and utilization issues, and a competing side reaction in the form of the H2evolution reaction (HER). Ethylene (C2H4) remains incredibly valuable within the chemical industry; however, the current established method for producing ethylene (steam cracking) contributes to the emission of CO2into the atmosphere. Thus, strategies to significantly increase the efficiency of this technology are essential. This review will discuss the vital factors influencing CO2RR in forming C2H4products and summarize the recent advancements in ethylene electrosynthesis.
more »
« less
Plastic from CO 2 , Water, and Electricity: Tandem Electrochemical CO 2 Reduction and Thermochemical Ethylene‐CO Copolymerization
Abstract Converting CO2into industrially useful products is an appealing strategy for utilization of an abundant chemical resource. Electrochemical CO2reduction (eCO2R) offers a pathway to convert CO2into CO and ethylene, using renewable electricity. These products can be efficiently copolymerized by organometallic catalysts to generate polyketones. However, the conditions for these reactions are very different, presenting the challenge of coupling microenvironments typically encountered for the transformation of CO2into highly complex but desirable multicarbon products. Herein, we present a system to produce polyketone plastics entirely derived from CO2and water, where both the CO and C2H4intermediates are produced by eCO2R. In this system, a combination of Cu and Ag gas diffusion electrodes is used to generate a gas mixture with nearly equal concentrations of CO and C2H4, and a recirculatory CO2reduction loop is used to reach concentrations of above 11% each, leading to a current‐to‐polymer efficiency of up to 51% and CO2utilization of 14%.
more »
« less
- Award ID(s):
- 2400314
- PAR ID:
- 10632989
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 24
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
The strong binding energy of CO on iron surfaces has rendered Fe electrodes as poor electrochemical CO2reduction (eCO2R) catalysts, predominantly producing hydrogen. Recent studies on tuning the microenvironment near the catalyst surfaces by tuning the local electric field in nonaqueous environments have been shown to promote eCO2R by facilitating the CO2activation step. Herein, the use of tetraethylammonium (TEA) cation to tune the electric field on Fe surfaces, such that it leads to the formation of industrially relevant oxalates (C2products), is reported. At optimal cation concentrations, the developed eCO2R system achieves 25 mA cm−2of current density and Faradaic Efficiencies up to 75% toward oxalate. Furthermore, in situ attenuated total reflectance Fourier transform infrared spectroscopy indicates the presence of surface‐adsorbed TEA cations and other species on the Fe surfaces, leading to the well‐known outer‐sphere mechanism of electron transfer during eCO2R. The employment of Fe, along with microenvironment tuning, not only demonstrates high catalytic performance but also provides a safer and more sustainable alternative to toxic catalysts such as Pb that dominate the nonaqueous eCO2R literature. These findings pave the way for further optimization and scale‐up of the process, offering a viable route for sustainable chemical production and CO2mitigation.more » « less
-
Abstract The electrochemical conversion of waste CO2into useful fuels and chemical products is a promising approach to reduce CO2emissions; however, several challenges still remain to be addressed. Thus far, most CO2reduction studies use pure CO2as the gas reactant, but CO2emissions typically contain a number of gas impurities, such as nitrogen oxides, oxygen gas, and sulfur oxides. Gas impurities in CO2can pose a significant obstacle for efficient CO2electrolysis because they can influence the reaction and catalyst. This Minireview highlights early examples of CO2reduction studies using mixed‐gas feeds, explores strategies to sustain CO2reduction in the presence of gas impurities, and discusses their implications for future progress in this emerging field.more » « less
-
To cut CO2emissions, we propose to directly convert shale gas into value-added products with a new H2/O2co-transport membrane (HOTM) reactor. A Multiphysics model has been built to simulate the membrane and the catalytic bed with parameters obtained from experimental validation. The model was used to compare C2 yield and CH4conversion rate between the membrane reactor and the state-of-the-art fixed-bed reactor with the same dimensions and operating conditions. The results indicate that (1) the membrane reactor is more efficient in consuming CH4for a given amount of fed O2. (2) The C2 selectivity of the membrane reactor is higher due to the gradual addition of O2into the reactor. (3) The current proposed membrane reactor can have a decent proton molar flux density but most of the proton molar flux will contribute to producing H2O on the feed side under the current operating conditions. The paper for the first-time projects the performance of the membrane reactor for combined H2O/H2removal and C2 production. It could be used as important guidance for experimentalists to design next generation natural gas conversion reactors.more » « less
-
Abstract In this work, the electroreduction of carbon dioxide (CO2) to oxalate is enabled by incorporating trace metallic lead (Pb) on carbon‐based supports (CBS) with polymer overlayers. These composite materials serve as an efficient electrocatalytic system for the facile conversion and storage of CO2, a pernicious atmospheric pollutant. Results from controlled potential electrolysis experiments indicate that 1) trace metallic Pb on the ppb scale is active toward the reductive coupling of CO2to oxalate at comparable Faradaic efficiencies to bulk metallic Pb and 2) polymer encapsulation of this trace metallic Pb leads to promotion of CO2reduction (CO2R) selectively to metal oxalates over other products such as CO. Importantly, metal oxalates are important alternative cementitious materials and precursors for other materials’ synthesis applications. The solid products undergo rigorous spectroscopic characterization, including13CO2labeling experiments, to ensure the metal oxalates are in fact produced from CO2R. These findings serve as a model for leveraging microenvironment effects to enhance activity and selectivity for CO2R using trace‐metal catalysts for carbon utilization and storage technologies.more » « less
An official website of the United States government

