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Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
08:00am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
CO2 hydrogenation to hydrocarbons over heterogeneous catalysts
08:00am - 08:40am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Society is faced with a CO2 dilemma – we need to slow our production of the gas while simultaneously developing efficient methods to capture, store and/or use it. My group has focused on CO2 capture for over a decade, designing porous materials and processes for CO2 separation from different gas mixtures, including flue gases and ambient air. More recently, we have focused our attention on the conversion of CO2 to useful products, such as hydrocarbons.
In this presentation, I will briefly describe some of the key approaches to CO2 capture, followed by a more detailed description of two approaches for CO2 conversion being explored in my group, (i) a chemical looping pathway based on high temperature CO2 capture coupled with in-situ hydrogenation of the captured CO2 to produce methane or methanol, and (ii) conversion of dilute CO2 into aromatics via a process intensification approach pairing methanol synthesis and zeolite catalysis. The performance of these (i) alkali-promoted supported metal and (ii) mixed metal oxide / zeolite hybrid catalysts will be described.

Sunday
Cesium-promoted ethanol production from CO2 hydrogenation on Cu/ZnO(000) surface: Full mechanistic study
08:40am - 09:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Dr Xuelong Wang, Presenter, Brookhaven National Laboratory; Pedro Ramírez; Dr Jose A Rodriguez, PhD, Chemistry Department; Ping Liu, Brookhaven National Laboratory
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Efficient conversions of CO2 into value-added chemicals such as alcohols are of great industrial and scientific interest. The Cu/ZnO/Al2O3 catalyst has been extensively studied and commercialized in the industry to produce C1 alcohol, methanol from CO2 hydrogenation. In contrast, for Cu-based catalysts, successful attempts to achieve the production of higher alcohols, such as ethanol, which is safer and offers higher energy density, are very limited, due to the difficulty in C-C bond coupling and thus low selectivity. Most Cu-based catalysts are active for the reverse water gas shift (RWGS) reaction and hydrogenation of CO rather; while the C-O bond activation is difficult, which hinders C-C bond formation. Promoters such as Fe have been reported previously, which can facilitate C-O bond dissociation over Cu catalysts. In addition, alkali metal promoters, including K and Cs, have also shown the capability of C chain growth over Cu-based catalysts. Yet, the reaction mechanism remains elusive.
Here, combining surface science experiments and DFT calculations, we present a detailed mechanistic understanding of the roles that Cs plays in ethanol production at the Cu-Cs-ZnO interface under CO2 hydrogenation condition. Our study not only leads to the discovery of new pathways for ethanol production from CO2 hydrogenation but also opens new possibilities to allow the highly active and selective CO2 conversion to higher alcohols on widely used and low-cost Cu-based catalysts.

Sunday
Development of a zero gap membrane electrode assembly carbon monoxide electrolyzer
09:00am - 09:20am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Carbon monoxide electroreduction is a rapidly developing field for the production of valuable chemicals. When coupled with CO2 capture and electrochemical conversion, it can be used as a clean CO2 negative process for the production of a variety of products. Carbon monoxide reduction has the distinct advantage over direct electrochemical CO2 reduction to multi-carbon products (C2+) in that it does not suffer from carbonate formation, allowing for higher feed conversion and electrolyte stability. This work focuses on the design and production of a zero gap membrane electrode assembly carbon monoxide electrolyzer which operates at low cell potentials (< 2.5 V) and industrially relevant current densities (> 300 mA/cm2) for the production of acetate and ethylene. Zero gap electrolyzers place the cathode and anode in direct contact with a conductive polymer membrane. This provides distinct advantages over conventionally studied three-compartment flow cell designs, where the cathode is in contact with an aqueous liquid electrolyte. Specifically, the use of a solid polymer membranes increases cell stability while decreasing the electrolyzer internal resistance. We demonstrate the high selectivity of the device for producing acetate and ethylene, achieving high Faradaic efficiencies as well as high molar production rates relative to other C2+ products. The system was also found to have improved current densities and cell voltages when compared to conventional three-compartment carbon monoxide electroreduction systems. The opportunity for products to be shuttled through the membrane, however, leads to a more complicated system when compared to three-compartment systems, where the products are solely captured in the catholyte. An investigation was therefore performed to determine both the anode’s as well as the membrane’s effects on the system’s product output and performance.
Sunday
Withdrawn
09:20am - 09:40am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person

Sunday
Efficient inteplay of ZrO2 and Ni0 for photocatalytic CO2 conversion into mehtane monitored using 13CO2 and EXAFS
09:40am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The reaction mechanism of CO2 photoreduction into methane was elucidated by the time-course monitoring of the mass chromatogram, in situ Fourier transform infrared (FTIR) spectroscopy, and in situ extended X-ray absorption fine structure (EXAFS). Under13CO2, H2, and UV–visible light, 13CH4 was formed at a rate of 0.98 mmol h−1 gcat−1using Ni (10 wt%)–ZrO2 that was effective at 96 kPa. Under UV–visible light irradiation, the 13CO2 exchange reaction and FTIR identified physisorbed/chemisorbed bicarbonate and the reduction because of charge separation in/on ZrO2, followed by the transfer of formate and CO onto the Ni surface (Scheme 1). EXAFS confirmed exclusive presence of Ni0 sites. Then, FTIR spectroscopy detected methyl species on Ni0, which was reversibly heated to 394 K owing to the heat converted from light based on the analysis of Debye-Waller factor changes obtained by EXAFS. Heat reactions were much slower (Figure 1). Using D2O and H2, H/D ratio in the formed methane was in agreement with H/D ratio in reactant. This study paves the way for using first row transition metals for solar fuel generation and on-site fuel supply on planets using only UV–visible light.
<b>Scheme 1.</b> Proposed intermediate species during CO<sub>2</sub> exchange and photocatalytic CO<sub>2</sub> reduction.

Scheme 1. Proposed intermediate species during CO2 exchange and photocatalytic CO2 reduction.

<b>Figure 1. </b>Time course of <sup>13</sup>CH<sub>4</sub> and <sup>12</sup>CH<sub>4</sub> formation during the catalytic test exposed to (A) <sup>13</sup>CO<sub>2</sub> (2.3 kPa), H<sub>2</sub>O (2.3 kPa), and H<sub>2</sub> (21.7 kPa) under UV-visible light and (B) at 393 K, under dark (first 24 h) followed by under UV-visible light (6 h) both using Ni (10 wt%)-ZrO<sub>2</sub>-Reduced (0.020 g).

Figure 1. Time course of 13CH4 and 12CH4 formation during the catalytic test exposed to (A) 13CO2 (2.3 kPa), H2O (2.3 kPa), and H2 (21.7 kPa) under UV-visible light and (B) at 393 K, under dark (first 24 h) followed by under UV-visible light (6 h) both using Ni (10 wt%)-ZrO2-Reduced (0.020 g).


Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
10:30am - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
Nanocrystal-based catalysts for CO2 hydrogenation to fuels and chemicals
10:30am - 10:50am USA / Canada - Eastern - August 22, 2021 | Room: B218
Matteo Cargnello, Presenter, Stanford University; Aisulu Aitbekova; Chengshuang Zhou, Stanford
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The conversion of CO2 to fuels and chemicals represents an important pathway towards a sustainable future. The reduction of CO2 using renewable hydrogen is heavily researched as one possible avenue. The main challenges associated with this process are the activation of the inert CO2 molecule as well as the control of the selectivity towards specific compounds. Designing catalysts where metal/support interfaces are controlled to exploit their synergy is a viable route to steer the selectivity of the reaction towards desired products such as long-chain hydrocarbons. Furthermore, understanding changes that occur to catalysts under the demanding reaction conditions necessary for CO2 hydrogenation is important to design more efficient materials. In this talk, I will highlight recent work from our group that uses colloidal nanocrystals to prepare well-defined catalysts with inorganic and organic/inorganic hybrid interfaces to control CO2 hydrogenation selectivity. These catalysts demonstrate in some cases specific changes under reaction conditions that lead to modified reactivity and increased production of hydrocarbons following structural rearrangements. In other cases, the specific design of hybrid interfaces allows to obtain materials with much improved selectivity towards desired products, thus highlighting how colloidal nanocrystals can be used to design efficient and selective catalysts for challenging transformations.
Sunday
Theoretical calculations of electrochemical reduction of CO2 to form hydrocarbons and alcohols
10:50am - 11:10am USA / Canada - Eastern - August 22, 2021 | Room: B218
Hannes Jonsson, Presenter, Univ of Iceland Fac SCI Vr II
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Results of calculations of the electrochemical reduction of CO2 and the competing hydrogen evolution reaction will be presented. Activation energy of the various elementary steps has been evaluated as a function of applied voltage as well as thermodynamic properties. It has been shown experimentally that copper electrodes can give rise to a wide range of products in electrochemical CO2 reduction and a key question is why copper is so special. Many aspects of the experimental measurements can be reproduced nicely by the theoretical calculations. The fact that the onset potential of formate and CO formation is similar can be explained by the fact that the energy barrier for the two competing processes is similar. The rate limiting step for further reduction is the hydrogenation of CO and the calculations show that a Heyrovsky step to form COH is the active mechanism rather than formation of CHO. An understanding of the detailed mechanism is important in order to find ways to improve the selectivity and to reduce the overpotential in order to make electrochemical CO2 reduction viable. Recent studies have, for example, shown that incorporation of CO2 into hydrate clathrates can significantly reduce the overpotential and favor CO2 reduction over hydrogen formation. The rate of C-C bond formation is strongly dependent on the surface structure and can be affected also by addition of small alloying component in the copper electrode. The extension of the simulation methodology to electrochemical reactions is challenging and represents an active front in the development of theoretical tools. Describing the effect of the electrostatic potential on the reaction rate is a challenge, but also the proper inclusion of a liquid dielectric at the surface of the electrode as it makes the DFT calculations too computationally demanding. Various levels of approximations have been developed and compared in the calculations of the electroreduction of CO2.
Sunday
Withdrawn
11:10am - 11:30am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person

Sunday
Intensified catalytic conversion of CO2 into C1 and C2 chemicals
11:30am - 11:50am USA / Canada - Eastern - August 22, 2021 | Room: B218
Dr. Jesse Thompson, Presenter, University of Kentucky Center for Applied Energy Research; Daniel Moreno; Muthu Kumaran Gnanamani; Pom Kharel; Keemia Abad; Ayokunle Omosebi
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The use of CO2 produced from power generation plants as a feedstock for creating valuable products offers a commercially viable strategy to reduce greenhouse gas (GHG) emissions and offset the cost of carbon capture. Despite years of CO2 conversion research, the development of efficient, robust, and selective heterogeneous CO2 reduction (CO2R) catalysts to convert CO2 into value-added compounds has yet to fully mature. In recent years, CO2R catalysts have become more sophisticated but still struggle with limited long-term activity. Producing value-added CO2 products via an electrochemical pathway can greatly depend on current density, Faradaic efficiency, electrode material and loading, and performance and material degradation.

To overcome the aforementioned limitations, development of a novel copper-based catalytic electrochemical system that can be used to convert carbon dioxide (CO2) to formic acid has been conducted. Formic acid (FA) is a high-value C1 chemical feedstock, but its current production process can require other high-valued chemicals as inputs, including methanol and/or hydrogen. In order to selectively convert CO2 to FA, Cu-based catalysts are commonly used. The metal-to-oxide interface of these catalysts can be tuned to offer higher peripheral metal-to-oxide interfacial area by alkylamine directed synthesis of morphology controlled metal layers formation on oxides.

The developed process leverages highly conductive mesoporous carbon xerogels electrodes, that have already been demonstrated as excellent supports in fuel cells, with Cu-based catalysts for the electrocatalytic conversion of CO2. Current results indicate that modifying CX cathodes with CuCo:CeO2 produces over 2X increase in FA compared only using Cu or CuCo at an operating voltage of -0.75 V vs. Ag/AgCl. Further FA selectivity customization is available in the -0.75 V to -1.0 V vs. Ag/AgCl range. Additionally, increasing the cell pressure from 1 to 3 bar to take advantage of the greater equilibrium concentration of CO2 increased FA production by over 5X, without compromising the structural integrity of the electrochemical cell.

Sunday
Combined electro-thermochemical system for conversion of waste carbon to C4+ synthetic fuels using 3D-printed reactors
11:50am - 12:10pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
With the realization of the global impact of waste carbon on the atmosphere, coupled with a clear and growing demand for abundant electricity, there are both environmental and economic driving forces for capturing and converting carbon dioxide (CO2) into high value hydrocarbon products. Two conversion approaches that have been studied extensively are the electrochemical CO2 reduction reaction (eCO2R) and the thermochemical Fischer-Tropsch reaction (F-T); however, leveraging the two reactions together for direct CO2 conversion to synthetic fuels has been challenging due to mismatched reactor size and scales of production, incompatible operating conditions, and poor stability of F-T catalysis in the presence of CO2-rich reactant streams.

This work employs advanced manufacturing to bridge the gap between these two technologies by creating custom 3D-printed reactors. These reactors were designed to align the scale of production for each reaction and consequently allow for a combined electrochemical-thermochemical approach for converting CO2 to C4+ synthetic fuels. A range of operating conditions for each process were investigated: for eCO2R, electrochemical potential and reactor geometry were tailored for maximum conversion of CO2 to CO and optimal ratio of H2:CO; for F-T, catalyst synthesis and operating temperature were studied for conversion of CO2-rich reactant streams to multi-carbon products at ambient pressure. As a result, we report a joint electro-thermochemical system that reaches a maximum of 20% single-pass conversion of CO2 that is stable for over 8 hours; furthermore, we achieve > 60% selectivity to C4+ products. This work represents a method to achieve high selectivity to desired products from CO2, as well as a viable path for scaling these technologies together for sustainable production of synthetic fuels and valuable products from waste carbon.

Sunday
Life cycle assessment of an integrated direct air capture system with advanced algal biofuel production
12:10pm - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
This study investigates the life cycle environmental impacts of options for integrating a solid amine-based DAC system with advanced algal biofuel production in photobioreactors (PBRs). DAC utilization allows the removal of atmospheric CO2 while also decoupling algae production facilities from anthropogenic point CO2 sources and avoiding the challenges of transporting CO2 long distances to remote facilities. Life cycle assessment is used to assess the environmental benefits of heat and mass integration between the DAC and the PBR for biofuel production. The analysis includes life cycle greenhouse gas emissions, water consumption, land use, criteria air pollutant emissions, and wastewater emissions. This presentation will discuss a range of options and will evaluate the potential for low carbon, sustainable biofuel through air capture of carbon dioxide.
Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
04:30pm - 06:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
Insights into the electrochemical conversion of CO2 to fuels and chemicals
04:30pm - 04:50pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Thomas Jaramillo, Presenter, Stanford University
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Ever-increasing carbon dioxide (CO2) emissions motivate the development of new processes to capture and utilize CO2 as a feedstock for the sustainable production of carbon-based fuels and chemicals. This paper will describe recent insights into electrochemical transformations involving CO2, a process that can be potentially powered by renewable electricity to convert CO2 and H2O into valuable products. This paper will focus on molecular-level insights into these chemical transformations, covering key factors that govern catalyst activity and selectivity. These include catalyst composition, surface structure, morphology, and the role of the electrolyte at the interface. This paper will describe how these insights can be leveraged in catalyst development, along with the integration of catalysts into high-performance devices.
Sunday
Electrosynthesis of amides by co-reduction of carbon dioxide and ammonia
04:50pm - 05:10pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
The CO2 electroreduction reaction (CO2RR) is a promising method to produce fuels and useful chemicals in a clean and sustainable way. Electricity can be derived from renewable energy sources, such as solar or wind, and can be converted into chemical energy stored in the form of chemical bonds. A variety of products (carbon monoxide, methanol, methane, ethanol, ethylene, n-propanol) can be produced by CO2RR. However, products with heteroatoms (ex. C and N) like acetamide or urea are carry even more commercial value. There is a recent push in co-reacting N-sources such as N2 or ammonia with CO2 to generate products with C-N bonds. However, there remains much to be done in terms of developing efficient reaction routes and unveiling the precise surface reaction mechanism.
To this end, we present a novel electrochemical system which co-reacts ammonia and CO2 at a gas-liquid-solid triple phase boundary to produce acetamide and formamide over Cu-based catalysts. Electrolysis experiments show that formamide is preferential to be formed on Cu catalysts, while CuO tend to produce acetamide. We combine electrochemical methods with in-situ spectroscopy to reveal the intermediate of the reactions and subsequently propose a likely set of reaction pathways. The faradaic efficiency (FE) of CuO reaches maximum for the formation of acetamide at -1.8V, which is 0.63%. While for Cu, the formation of formamide reaches maximum (0.32% FE) at -2.0V. As the formation of acetamide and acetate share the same intermediate, the production of formamide and formate may also undergo the same reaction pathway at the initial stage of the reaction.

Sunday
Opportunities and limits of CO2 utilization pathways: Techno-economics, critical infrastructure needs, and policy priorities
05:10pm - 05:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Amar Bhardwaj, Presenter, Columbia University; Colin McCormick; Julio Friedmann
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Despite growing efforts to drastically cut carbon dioxide (CO2) emissions and address climate change, energy outlooks project that the world will continue to rely on certain products that are currently carbon-intensive to produce but have limited alternatives, such as aviation fuels. Converting CO2 into valuable chemicals, fuels, and materials has emerged as an opportunity to reduce the emissions of these products. However, CO2 utilization processes have largely remained costly and difficult to deploy, underscoring the need for supportive policies informed by analysis of the current state and future challenges of CO2 utilization. This work analyzes 19 electrocatalytic and thermocatalytic CO2 utilization pathways to understand the opportunities and the technical and economic limits of CO2 utilization products gaining market entry and reaching global scale. The analyzed pathways include electrochemical CO2 reduction to produce a range of products, along with thermocatalytic pathways such as CO2 hydrogenation and Fischer-Tropsch synthesis to produce various fuels and chemicals. The pathways are designed to consume renewable electricity and use chemical feedstocks derived from electrochemical pathways powered by renewable energy. Across these CO2 utilization pathways, we evaluated current production costs, sensitivities to cost drivers, carbon abatement potential, critical infrastructure and feedstock needs, and the effect of subsidies. We find that the costs of most pathways are high, and are dominated by the cost of electricity and feedstocks. Based on these cost estimates, we identify the most economic CO2 utilization pathways for early market entry and recommend demand pull policies to begin deploying them. The strongest driver for cost reductions is catalyst selectivity and activity, motivating greater RD&D funding for catalyst innovation to bring down costs. We also find that CO2 utilization pathways at global scale would each require trillions of dollars of investment in supporting infrastructure and would consume thousands of terawatt hours of electricity annually. Therefore, a concurrent focus on building out necessary infrastructure is needed to support the scale-up of CO2 utilization. With the proper approach to advancing CO2 utilization, we find these pathways could abate gigatonnes of CO2 per year at global scale.
Sunday
Effect of addition of catalysts/additives on CO2 absorption rates via controlled bubble generation in CCS solvents
05:30pm - 05:50pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Dr. Moushumi Sarma, Presenter, University of Kentucky; Jesse Thompson; Kunlei Liu
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
The emission of greenhouse gas, CO2 from fossil fuel combustion contributes to a potential negative impact on the environment and thus has been the subject of widespread attention over the past few decades. Using amine-based solutions for CO2 capture in power plants is the most common method utilized industrially and studied in the laboratory environment. However, a limited number of amines are available for carbon capture research after balancing the capital cost and energy penalty. In the CCS process, physical properties such as surface tension, wettability, viscosity, etc. are found to play vital roles in solvent performance capturing CO2 in the absorber column. These properties affect the wettability of the solvent on the column packing material and the contact of gas with the solvent. In this context, we are exploring an approach to enhance the CO2 capture of amine solvents by utilizing the controlled bubble formation to increase liquid-gas contact surface area and CO2 mass transfer into the solvent. This is achieved by tuning the physical properties of the amine solvents by the addition of catalysts/additives. This method has been shown to increase CO2 mass transfer in the absorber column, specifically at the bottom where the mass transfer is limited as the reaction kinetics have slowed down. This work can be applied to all common aqueous amine solvents and would be of great interest to those in the CCS community.

Sunday
Role of ionic liquid electrolytes and their cations as a promoter for CO2 electrocatalysis
05:50pm - 06:10pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Bjoern Ratschmeier; Andre Kemna; Dr. Björn Braunschweig, Presenter, University Münster
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Room-Temperature Ionic Liquids (IL) play an important role in lowering CO onset potentials for CO2 reduction reactions (CO2RR), but the reaction mechanism is still controversial. By using in operando IR absorption spectroscopy (IRAS) and in situ sum-frequency generation (SFG) spectroscopy we provide new information on the role of the cation for CO2RR. For this purpose, we have investigated CO2RR on polycrystalline Pt electrodes using 1-Butyl-3-methylimidazolium [BMIM], 1-Butyl-1,3-dimethylimidazolium [BMMIM] and 1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPyrr][NTf2] with 10 mM and 500 mM H2O. Cyclic voltammetry indicates CO2RR reduction activity for all three systems, with highest current densities for [BMMIM][NTf2]. Spectroscopic investigation revealed a CO onset potential of -0.7 V vs. SHE for [BMMIM] and [BMPyrr][NTf2] which is independent on variation of the H2O concentration and where CO formation can occur via an electrostatically stabilized CO2 radical anion. On the other side [BMIM][NTf2] shows strong dependence on H2O with an onset potential of -0.4 V at 500 mM H2O and the formation of an imidazolium-2-carboxylic acid as an reactive intermediate.
Sunday
In situ spectroscopic study of electrochemical CO2/NO reduction reaction
06:10pm - 06:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 29
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Metal-catalyzed conversion of carbon dioxide and nitric oxide which are two serious greenhouse gases, to valuable fuels by renewable electricity is an effective strategy for combatting climate change. Despite recent research on electrocatalytic reduction of CO2 and NO, the surface speciation of the metal surface during reaction condition remains a topic of discussion. Determining the surface species via operando characterization is crucial to understand the reaction mechanisms as well as improve the reactivity performance. Surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared adsorption spectroscopy (SEIRAS) are two powerful techniques with high surface sensitivity and selectivity, which are ideally suitable for determining the transformation on the surface.
First, we employ SERS to investigate the speciation of five different Cu catalysts (i.e., Cu micro/nanoparticles, electrochemically deposited Cu, chemically deposited Cu, Cu foil) in electrochemical CO reduction reaction, a key step in CO2 reduction for further production of valuable C2+ products. Multiple oxide and hydroxide are observed in these Cu surfaces, while the species on Cu foil is distinct from others. This difference is related to the oxidative state prior to the applied negative potential. Combining the reactivity and spectroscopic results, we conclude the oxygen containing species on these Cu catalysts are unlikely to be active in facilitating the C2+ oxygenates in the CO reduction reaction.
Second, SEIRAS is used to study the different selectivity toward N2O, N2 and NH3 during electrochemical NO reduction on Pt and Pd. NO adsorbed on atop and bridge sites are both exist on Pt and Pd under acid solution, while the dominate bridge bonded NO on Pt over Pd under more negative potentials contributes to the preferred NH3 production on Pt. The adsorption of NO is determined to be dependent on pH as it shifts from atop site to bridge site when the electrolyte switches from acid to alkaline solution. Besides, Cu has been demonstrated to be more effective to convert NO to NH3, the weak adsorption of NO however hinders its detection on SEIRAS.

Experimental & Computational Approaches to Molecular-Scale Understanding of Mineral-Fluid Interactions: Symposium in honor of R. James Kirkpatrick:
04:30pm - 06:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Geoffrey Bowers, Organizer, St. Mary's College of Maryland; Andrey Kalinichev, Organizer, IMT Atlantique Bretagne-Pays de la Loire - Campus de Nantes; Narasimhan Loganathan, Organizer; Ozgur Yazaydin, Organizer; Andrey Kalinichev, Presider, IMT Atlantique Bretagne-Pays de la Loire - Campus de Nantes; Geoffrey Bowers, Presider, St. Mary's College of Maryland; Narasimhan Loganathan, Presider; Ozgur Yazaydin, Presider
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual
Division/Committee: [GEOC] Division of Geochemistry

Most geochemical reactions occur at mineral-fluid interfaces or in the confined spaces of mineral interlayers and nano-pores. These reactions affect many important natural and engineered processes, such as mineral weathering, adsorption or release of environmental contaminants in soil and ground water, flotation and other mineral processing technologies, cement and concrete corrosion and degradation, geological disposal of radioactive waste, geological carbon sequestration, exploration of nonconventional hydrocarbon resources by hydraulic fracturing of host rocks, etc. Molecular-scale view of these systems is critical for their understanding and practical application. Over several decades, Jim Kirkpatrick was on the forefront of these studies and his research group has contributed a lot to our present-day molecular scale understating of the physical and chemical phenomena controlling the properties of such interfacial and nano-confined systems. This session is dedicated to his memory and invites contributions highlighting the most recent advances in the studies of mineral-fluid interfaces using NMR, X-ray, neutron scattering, and other experimental techniques, especially in their close coupling with atomistic computational modeling approaches.

Sunday
Introductory Remarks
04:30pm - 04:35pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual

Sunday
Passivation effect during forsterite carbonation in thin H2O films
04:35pm - 05:05pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
John Loring, Presenter; Sebastian Mergelsberg, Pacific Northwest National Laboratory; Christopher Thompson; Odeta Qafoku; Eugene Ilton; Sebastien Kerisit, Pacific Northwest National Laboratory
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual
Previous studies of divalent orthosilicate dissolution in bulk water have evidenced tens of nm thick M2+-depleted/silica rich coatings on reacted parent minerals. These altered surface layers are believed to form by either M2+ leaching and repolymerization of relic SiO4 tetrahedra or congruent dissolution followed by precipitation of SiO2(am). They significantly slow orthosilicate dissolution by reducing the number of reactive surface sites and hindering the release of M2+ that must now diffuse through porous channels in the SiO2(am). We have observed a passivating effect during the carbonation of forsterite (Mg2SiO4) in confined H2O films that are Å-to-nm in thickness under wet supercritical CO2 conditions relevant to geologic carbon sequestration. For example, the carbonation of ~30 nm sized forsterite particles in humidified scCO2 proceeds rapidly for the first ~24 hours but then dramatically slows so that only ~ 20% of the forsterite is consumed after 3 days of reaction. This results in a SiO2(am) layer that is less than 1 nm thick. Interestingly, carbonation of the same nano-sized forsterite in bulk water with a 90 bar CO2 headspace leads to complete reaction in ~24 hours with no apparent passivation effect. In this presentation, we will share results from a combination of in situ infrared and electrical impedance spectroscopic results that reveal a passivation mechanism during forsterite carbonation in thin H2O films. Our findings suggest that the secondary SiO2(am) dramatically reduces dissolution/carbonation rates. The inferred mechanism is distinct from bulk-water studies and is dependent on H2O film thickness. This study furthers an understanding of divalent silicate carbonation under low-H2O CO2-dominated fluids as part of a comprehensive effort to predict the fate of CO2 stored in geologic reservoirs.
Sunday
Co-existing iron minerals influence ferrihydrite Fe(II)-catalyzed transformation pathways
05:05pm - 05:20pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual
In sub- or anoxic conditions, reactions between ferric iron (Fe(III)) minerals with dissolved ferrous iron (Fe(II)) tend to transform minerals with lower crystallinity, such as ferrihydrite, into more crystalline phases, while thermodynamically stable minerals, such as goethite, tend to undergo recrystallization rather than transformation. However, in nature, minerals of varying crystallinity co-exist, and we still lack an understanding of how co-existing minerals could influence transformation or recrystallization pathways in heterogeneous systems. To learn how ferrihydrite (Fh) and goethite (Gt) interact with Fe(II) in a heterogeneous system, we reacted synthetic mixtures of Fh and Gt with 1 mM Fe(II) for 24 hours and followed the transformation products and kinetics using XRD and Rietveld fitting. Our results suggest that the co-existence of goethite with ferrihydrite leads to a faster transformation of ferrihydrite into goethite. To further investigate the mechanism that leads to faster transformation into goethite, in subsequent experiments, we isolated each Fe pool (Fh, Gt, and Fe(II)) with a different stable Fe isotope (e.g., 54Fe, 56Fe, 57Fe) and followed the fate of the atoms using a combination of 57Fe Mössbauer spectroscopy and ICP-MS. In the absence of goethite, atoms initially in the aqueous phase formed mostly lepidocrocite and some goethite, while atoms initially in ferrihydrite formed mostly goethite but also some lepidocrocite. In the presence of goethite, atoms from the aqueous phase formed a much higher fraction of goethite, which can be explained by Fe(II)-goethite electron transfer. Atoms from ferrihydrite still transformed into goethite and lepidocrocite, but a fraction of the formed goethite had very low crystallinity. We hypothesize that the new layer of goethite formed by Fe(II)-goethite electron transfer acts as a template and provides an extra pathway for the transformation of ferrihydrite into goethite. Our results demonstrate that the co-existence of goethite alters ferrihydrite transformation in the presence of Fe(II) and suggest the Fe atoms in the surrounding minerals should be considered when investigating mineral transformation and recrystallization in natural soils.
Sunday
Intermission
05:20pm - 05:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual

Sunday
Wet non-aqueous fluid behavior in solids with multi-scale porosity
05:30pm - 06:00pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Geoffrey Bowers, Presenter, St. Mary's College of Maryland; John Loring; H. Schaef; Eric Walter; Brian Smith
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual
Jim Kirkpatrick provided some of the foundational work on the behavior of water in nm-scale confined spaces and in the proximity of solid surfaces – newly forming carbonates, smectite clays, layered double hydroxides, and natural organic matter. While collaborating on some of that work with Jim, I became very interested in the behavior of fluids important in shale and tight gas reservoirs (supercritical methane and carbon dioxide) in these same environments. Over the last five years, my group and many key collaborators made several important contributions regarding the behavior of supercritical methane (scCH4) and carbon dioxide (scCO2) in porous solids at conditions equivalent to ~1 km underground. Using novel high-pressure NMR rotors, high-pressure XRD, and high-pressure IR, we showed that scCO2 actively enters the 2D slit pores of smectite interlayers while scCH4 can only passively enter interlayer domains if the basal spacing permits its entry. We also showed that 13CO2 NMR is sensitive to the mean angle between the CO2 bond axis and the basal surface of clay minerals and evidence for two mechanisms of scCO2 trapping by smectite clays. Other studies of smectites with sc13CH4 NMR contributed important evidence toward the theory of dynamic basal spacing fluctuations, that the 13C chemical shift of scCH4 is sensitive to mean dynamic pore size, and that exchange spectroscopy (EXSY) NMR can quantify scCH4 exchange between interlayer micropores and other pore types in the packed powders. More recently, we have shown a ln-linear correlation between the 13C chemical shift of scCH4 and the mean diameter of 1D cylindrical silica mesopores. We also have quantified the exchange rates and exchange rate distributions for scCH4 hopping between silica mesopores and larger pore types. This talk will provide a review of this work in memorial of RJK and some preliminary data from ongoing studies of scCH4 in functionalized silicas.
Sunday
Development of improved molecular models of complex environmental phases and their interfaces
06:00pm - 06:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 40
Dr. Randall T. Cygan, Presenter, Texas A&M University
Division: [GEOC] Division of Geochemistry
Session Type: Oral - Virtual
Molecular understanding of interfacial structure and reactivity of minerals in aqueous environments is critical for the treatment of chemical contaminants, safe disposal of radioactive waste, improved gas and oil extraction, and carbon sequestration to mitigate climate change. Basal surfaces and interlayers of clay minerals, in particular, provide structurally constrained-interfacial environments to better evaluate these complex processes. We use large-scale classical molecular dynamics simulations to examine the interfacial structure and adsorption behavior associated with smectite, kaolinite, and other clay mineral phases. The models offer insights into the mechanisms controlling adsorption, hydration, wetting, interlayer swelling, electrical double layer, diffusion, and related phenomena. In particular, molecular dynamics simulations involving clay interlayers provide models of nanopores where confinement and limited transport can impact interfacial structure and aqueous behavior. Combined with analytical methods such as NMR and neutron spectroscopies, molecular simulation offers a powerful approach for interpreting complex structure and behavior of important environmental phases. A historical perspective—covering several decades of collaboration with R. James Kirkpatrick and his colleagues—provides context on his significant scientific contributions.
Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
07:00pm - 09:00pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
Mechanisms of (photo)electrochemical conversion of CO2 to fuels from first principles
07:00pm - 07:20pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Emily Carter, Presenter
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
This Keynote talk will present recent mechanistic insights gleaned from state-of-the-art quantum mechanics computations of photoelectrocatalytic and electrocatalytic reduction of CO2 to a variety of products, including formic acid, methanediol, and methanol, among others. The product distribution depends is, unsurprisingly, highly electrode-dependent. For photoelectrochemical reduction, we find that hydride transfer dominates the chemistry, rather than proton-coupled electron transfer. Further, we find CdTe stops at formic acid (as seen experimentally), metal-rich facets of GaP stop at methanediol, while reduction all the way to methanol occurs on other facets of GaP and CuInS2. For electrocatalysis on metal electrodes, we show the critical need to describe electron transfer using embedded correlated wavefunction theory rather than pure density functional theory, in order to obtain electrochemistry consistent with observed onset potentials. Mechanistic predictions are strikingly different between the two theories, suggesting a need to revisit past mechanistic assessments that have used the less expensive method.
Sunday
Dual functional perovskite-based catalysts for CO2 sorption and syngas production
07:20pm - 07:40pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Soham Shah, Presenter, University of California Riverside; Kandis Gilliard-AbdulAziz, University of California Riverside; Mingjie Xu; Xiaoqing Pan
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
The capture of CO2 from large point sources and subsequent conversion to useful products is seen as a potential solution to alleviate the effects anthropogenic climate change. Dual Functional Materials (DFM) allow for the capture of carbon dioxide by combining sorption of CO2 on the surface and conversion over to catalytic sites to react with reducing gases, often H2, CH4 or C2H6. Perovskite oxides have noted tunable redox and catalytic properties by introduction of stoichiometric defects and substitution of metals. In our previous work we have discussed the use of Ni substituted LaFeO3 type perovskites tailored for catalysis of methane-carbon dioxide reforming. In this work we discuss CO2 capture and conversion with Sr based perovskites with Ni substitution as DFMs. We synthesized Ni supported on SrZrO3 and SrTiO3 type perovskites and tested them for methane dry reforming in co-fed and looping modes and CO2 reduction by CH4 and H2. Strontium or other alkali metals in perovskites as strong basic sites that can sorb CO2 in the form of surface carbonate species. Nickel atoms are the sites for catalytic activity where adsorbed CO2 reacted with methane/hydrogen. Stoichiometric defects altered the nature of basic sites available with A-site deficient samples having more of the weakly basic sites.
Sunday
Engineering the Cu/Mo2CTx catalytic activity: CO2 hydrogenation to methanol
07:40pm - 08:00pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Miss Anna Vidal, P.h.D Student, Presenter, Autonomous University of Barcelona; Aleix Comas-Vives; Estefanía Díaz López
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
CO2 emissions are negative for the global environment due to their role in climate change and ocean acidification. It is key to using CO2 as a raw material precursor of high-energy-density materials to ease the energy transition. The CO2 hydrogenation to methanol is a promising possibility for this purpose.

A non-precious-based catalyst based on a single-atom Cu catalyst supported on Mo2CTx displays higher activity than the industrial Cu/ZnO/Al2O3 reference system. To further understand the CO2 hydrogenation on Cu/Mo2CTx, we performed DFT calculations using our developed model for the support.

Our results show the crucial role played by the Cu@Mo2C interface in providing a low energy pathway the CO2 hydrogenation to methanol. Both the Cu atom and Mo2CTx participate in the reaction mechanism. They allow the successive heterolytic cleavages of H2 required to form HCOO *, H2COO *, and H2COOH * species, simultaneously with adsorbed H *. CH3OH forms easily, together with CO under reaction conditions.

These discoveries open new avenues for the hydrogenation of CO2 taking advantage of metal-support interactions and considering the role of Cu/MXenes interfaces.

Sunday
Hydrogenation of CO2 to methanol on a Auδ+–In2O3–x Catalyst: Boosting conversion, selectivity, and stability through metal-support interaction
08:00pm - 08:20pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
CO2 hydrogenation to methanol has attracted increasing attention with the development of renewable hydrogen. Here we report an In2O3 supported Au catalyst that exhibits excellent performance for hydrogenation of CO2 selectively to methanol. In-situ characterizations using time-resolved X-ray diffraction (TR-XRD), ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), and X-ray absorption spectroscopy (XAS) confirm that a strong metal-support interaction leads to a reactive Auδ+-In2O3-x interface for activation and hydrogenation of CO2 to methanol. An effective gold-indium oxide bonding favors the dispersion of the noble metal and prevents its sintering under reaction conditions. The methanol selectivity reaches 67.8% at 300 °C with a space time yield (STY) of methanol of 0.47 gMeOH/(h gcat). The strong metal-support interaction was also confirmed theoretically by performing density functional theoretical (DFT) calculation on a Au4/In2O3 model catalyst. This interaction causes the electron redistribution at the interfacial sites and leads to a positively charged Auδ+ cluster instead of metallic Au0, consisting with the in-situ characterization results. This electron redistribution facilitates the methanol synthesis by several ways: leading to an active and positively charged Au4 cluster for H2 dissociation; providing Au-In2O3 interfacial sites for CO2 activation and intermediates to be hydrogenated to methanol; and benefiting the removal of hydroxyl to prohibit the catalyst deactivation. All these effects account for the fact that Au/In2O3 catalyst is a promising candidate for the methanol synthesis from CO2 selective hydrogenation. Our study shows that the strong Au-In2O3 interaction and the intrinsic chemical activity of In2O3 can be used to significantly improve the catalytic performance of Au catalysts, providing promising routes for the rational design and application of Au catalyst beyond CO2 hydrogenation.
Sunday
Anion and cation-dependent selectivity and activity in CO2 electroreduction on Cu catalysts
08:20pm - 08:40pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Samaneh Sharifi Golru, Presenter, City University of New York; Prof. Elizabeth J Biddinger, PhD, The City College of New York
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Global warming due to emission of greenhouse gases like CO2 has been recently one of the most important environmental problems. CO2 electroreduction (CO2ER) can be a feasible method to mitigate the CO2 level in the atmosphere and produce valuable chemicals. Product selectivity in CO2 electroreduction is influenced by several factors such as catalyst material and electrolyte composition. Among electrolytes used in CO2ER, aqueous solutions are the most common electrolytes for CO2ER. However, the presence of the parasitic hydrogen evolution reaction (HER) reduces the selectivity for CO2ER. Using additives in aqueous electrolytes can be a promising method to enhance the selectivity and activity in CO2ER. Additives have an ability to stabilize the intermediates and also increase the CO2 concentration at the interface. Herein, we have investigated the effect of anions and cations of additives (10 mM) in the aqueous electrolyte (0.1 M KHCO3) on CO2ER over Cu.
To study the anion and cation effect, ILs and salts consisting of 1-butyl-3-methylimidazolium ([BMIM]+) or sodium (Na+) as cation and bis(trifluoromethylsulfonyl)imide ([NTF2]-) or dicyanamide ([DCA]-)) as anion were used. It was found that although both cations and anions influence CO2ER, the effect of anions is more pronounced. The results showed that formate formation was significantly enhanced in NTF2-based electrolytes. The maximum faradaic efficiency (FE) for formate (38.7%) was observed for [BMIM][NTF2] at -0.92 V vs. RHE. This observation can be due to high hydrophobicity and CO2 absorption capacity of the NTF2-salts. Moreover, [BMIM]+ cations have been reported to enhance CO2ER by stabilizing the intermediates on the surface. In contrast, [DCA]-based salts showed a high selectivity for HER and a very low selectivity for hydrocarbons even at high overpotentials. We attributed this observation to the strongly adsorption of [DCA]- on the surface. X-ray photoelectron spectroscopy (XPS) also confirmed the presence of adsorbed [DCA]- on the surface when using both Na[DCA] and [BMIM][DCA]. Electrochemical impedance spectroscopy (EIS) also revealed that [DCA]--based salts showed a smaller charge transfer resistance compared to [NTF2]- -based salts which can be due to significantly enhanced HER which is kinetically facilitated than CO2ER. In-situ electrochemical quartz crystal microbalance (EQCM) also showed a higher mass loss for DCA-salts probably due to the displacement of water molecules by ions.

Sunday
COx electrochemical reduction with additive molecules towards longer chain products
08:40pm - 09:00pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 27
Kavitha Chintam, Presenter, Northwestern University; Dr. Linsey C Seitz, PhD, Northwestern University
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Virtual
Conventional production of carbon-based fuels and chemicals contributes significantly to greenhouse gas emissions and climate change, increasing the urgency to develop mitigation or capture technologies. Electrochemical carbon dioxide/monoxide reduction (COxRR) is a promising alternative route for production of carbon-based fuels and chemicals; it requires mild electrolyzer operating conditions, integrates well with renewable energy sources, and enables flexibility of possible product selectivity. Engineering tunable systems is necessary to ensure critical chemicals and fuels are produced according to their relative demand. Although products with one or two carbons can be formed with reasonable selectivity on copper (Cu), tunability must be improved to enable production of longer carbon chain molecules.

Ethylene acts as a chain initiator itself as well as a source of C1 monomer species which promote chain propagation and can potentially improve COxRR tunability as in Fischer-Tropsch. A custom cell was designed to perform COxRR experiments with ability to control flow rates of COx and ethylene separately. Preliminary data suggests that ethylene increases the amount of methane, ethane, and propane formed and generates higher current compared to baseline COxRR with only CO2, both on Cu and in 0.1M potassium bicarbonate. Longer chain products also begin forming at lower absolute potentials than that of the baseline. Gaseous and liquid products are analyzed as a function of COx and ethylene flow rates, applied potential, and reaction environment.

Considering other possible additives, biofuel production generates byproducts like oxalates, acetaldehydes, and glyoxylic acids. These bioprivileged molecules can be repurposed and added to COxRR feedstreams to act as chain propagators. Co-electroreduction of COx and oxalate are investigated for novel product distributions as a function of electrolyte concentration and pH. Both additive strategies ultimately inform the viability of CO2RR as a greener pathway to carbon-based fuels and chemicals.