Browsing by Author "Gabardo, Christine M."
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Item Catalyst synthesis under CO2 electroreduction favours faceting and promotes renewable fuels electrosynthesis(Nature Research, 2019-12-16) Wang, Yuhang; Wang, Ziyun; Dinh, Cao-Thang; Li, Jun; Ozden, Adnan; Kibria, Md Golam; Seifitokaldani, Ali; Tan, Chih-Shan; Gabardo, Christine M.; Luo, Mingchuan; Zhou, Hua; Li, Fengwang; Lum, Yanwei; McCallum, Christopher; Xu, Yi; Liu, Mengxia; Proppe, Andrew; Johnston, Andrew; Todorovic, Petar; Zhuang, Tao-Tao; Sinton, David; Kelley, Shana O.; Sargent, Edward H.The electrosynthesis of C2+ hydrocarbons from CO2 has attracted recent attention in light of the relatively high market price per unit energy input. Today’s low selectivities and stabilities towards C2+ products at high current densities curtail system energy efficiency, which limits their prospects for economic competitiveness. Here we present a materials processing strategy based on in situ electrodeposition of copper under CO2 reduction conditions that preferentially expose and maintain Cu(100) facets, which favour the formation of C2+ products. We observe capping of facets during catalyst synthesis and achieve control over faceting to obtain a 70% increase in the ratio of Cu(100) facets to total facet area. We report a 90% Faradaic efficiency for C2+ products at a partial current density of 520 mA cm−2 and a full-cell C2+ power conversion efficiency of 37%. We achieve nearly constant C2H4 selectivity over 65 h operation at 350 mA cm−2 in a membrane electrode assembly electrolyser.Item Combined high alkalinity and pressurization enable efficient CO2 electroreduction to CO(Royal Society of Chemistry, 2018-06-21) Gabardo, Christine M.; Seifitokaldani, Ali; Edwards, Jonathan P.; Dinh, Cao-Thang; Burdyny, Thomas; Kibria, Md Golam; O’Brien, Colin P.; Sargent, Edward H.; Sinton, DavidThe electroreduction of CO2 to CO is a promising strategy to utilize CO2 emissions while generating a high value product. Commercial CO2 electroreduction systems will require high current densities (>100 mA/cm2)as well as improved energetic efficiencies (EEs), achieved via high CO selectivity and lowered applied potentials. Here we report a silver-based system that exhibits the lowest overpotential among CO2-to-CO electrolyzers operating at high current densities, 300 mV at 300 mA/cm2, with near unity selectivity. We achieve these improvements in voltage efficiency and selectivity via operation ina highly alkaline reaction environment(which decreases over potentials) and system pressurization (which suppresses the generation of alternative CO2 reduction products), respectively. In addition, we report a new record for the highest half-cell EE(>80%) for CO production at 300 mA/cm2.Item Constraining CO coverage on copper promotes high-efficiency ethylene electroproduction(Nature Research, 2019-11-11) Li, Jun; Wang, Ziyun; McCallum, Christopher; Xu, Yi; Li, Fengwang; Wang, Yuhang; Gabardo, Christine M.; Dinh, Cao-Thang; Zhuang, Tao-Tao; Wang, Liang; Howe, Jane Y.; Ren, Yang; Sargent, Edward H.; Sinton, DavidThe availability of inexpensive industrial CO gas streams motivates efficient electrocatalytic upgrading of CO to higher-value feedstocks such as ethylene. However, the electrosynthesis of ethylene by the CO reduction reaction (CORR) has suffered from low selectivity and energy efficiency. Here we find that the recent strategy of increasing performance through use of highly alkaline electrolyte—which is very effective in CO2RR—fails in CORR and drives the reaction to acetate. We then observe that ethylene selectivity increases when we constrain (decrease) CO availability. Using density functional theory, we show how CO coverage on copper influences the reaction pathways of ethylene versus oxygenate: lower CO coverage stabilizes the ethylene-relevant intermediates whereas higher CO coverage favours oxygenate formation. We then control local CO availability experimentally by tuning the CO concentration and reaction rate; we achieve ethylene Faradaic efficiencies of 72% and a partial current density of >800 mA cm−2. The overall system provides a half-cell energy efficiency of 44% for ethylene production.Item Constraining CO coverage on copper promotes high-efficiency ethylene electroproduction(Nature Research, 2019-11-11) Li, Jun; Wang, Ziyun; McCallum, Christopher; Xu, Yi; Li, Fengwang; Wang, Yuhang; Gabardo, Christine M.; Dinh, Cao-Thang; Zhuang, Tao-Tao; Wang, Liang; Howe, Jane Y.; Ren, Yang; Sargent, Edward H.; Sinton, DavidThe availability of inexpensive industrial CO gas streams motivates efficient electrocatalytic upgrading of CO to higher-value feedstocks such as ethylene. However, the electrosynthesis of ethylene by the CO reduction reaction (CORR) has suffered from low selectivity and energy efficiency. Here we find that the recent strategy of increasing performance through use of highly alkaline electrolyte—which is very effective in CO2RR—fails in CORR and drives the reaction to acetate. We then observe that ethylene selectivity increases when we constrain (decrease) CO availability. Using density functional theory, we show how CO coverage on copper influences the reaction pathways of ethylene versus oxygenate: lower CO coverage stabilizes the ethylene-relevant intermediates whereas higher CO coverage favours oxygenate formation. We then control local CO availability experimentally by tuning the CO concentration and reaction rate; we achieve ethylene Faradaic efficiencies of 72% and a partial current density of >800 mA cm−2. The overall system provides a half-cell energy efficiency of 44% for ethylene production.Item Continuous Carbon Dioxide Electroreduction to Concentrated Multi-carbon Products Using a Membrane Electrode Assembly(Elsevier, 2019-08-21) Gabardo, Christine M.; O’Brien, Colin P.; Edwards, Jonathan P.; McCallum, Christopher; Xu, Yi; Dinh, Cao-Thang; Li, Jun; Sargent, Edward H.; Sinton, DavidElectrochemical carbon dioxide (CO2) reduction is a promising strategy to synthesize valuable multi-carbon products (C2+) while sequestering CO2 and utilizing intermittent renewable electricity. For industrial deployment, CO2 electrolyzers must remain stable while selectively producing concentrated C2+ products at high rates with modest cell voltages. Here we present a membrane electrode assembly (MEA) electrolyzer that converts CO2 to C2+ products. We perform side-by-side comparisons of state-of-art electrolyzer systems and find that the MEA provides the most stable cell voltage and product selectivity. We then demonstrate an approach to release concentrated gas and liquid products from the cathode outlet. This strategy achieves ~50% and ~80% Faradaic efficiency for ethylene and C2+ products, respectively, with cathode outlet concentrations of ~30% ethylene and the direct production of ~4 wt.% ethanol. We characterize stability by operating continuously for 100 hours, the longest stable ethylene production at current densities >100 mA cm-2 among reported CO2 electrolyzers.Item Cooperative CO2-to-ethanol conversion via enriched intermediates at molecule–metal catalyst interfaces(Nature Research, 2019-12-16) Li, Fengwang; Li, Yuguang C.; Wang, Ziyun; Li, Jun; Nam, Dae-Hyun; Lum, Yanwei; Luo, Mingchuan; Wang, Xue; Ozden, Adnan; Hung, Sung-Fu; Chen, Bin; Wang, Yuhang; Wicks, Joshua; Xu, Yi; Li, Yilin; Gabardo, Christine M.; Dinh, Cao-Thang; Wang, Ying; Zhuang, Tao-Tao; Sinton, David; Sargent, Edward H.Electrochemical conversion of CO2 into liquid fuels, powered by renewable electricity, offers one means to address the need for the storage of intermittent renewable energy. Here we present a cooperative catalyst design of molecule–metal catalyst interfaces with the goal of producing a reaction-intermediate-rich local environment, which improves the electrosynthesis of ethanol from CO2 and H2O. We implement the strategy by functionalizing the copper surface with a family of porphyrin-based metallic complexes that catalyse CO2 to CO. Using density functional theory calculations, and in situ Raman and operando X-ray absorption spectroscopies, we find that the high concentration of local CO facilitates carbon–carbon coupling and steers the reaction pathway towards ethanol. We report a CO2-to-ethanol Faradaic efficiency of 41% and a partial current density of 124 mA cm−2 at −0.82 V versus the reversible hydrogen electrode. We integrate the catalyst into a membrane electrode assembly-based system and achieve an overall energy efficiency of 13%.Item Designing anion exchange membranes for CO2 electrolysers(Nature Research, 2021-02-11) Salvatore, Danielle A.; Gabardo, Christine M.; Reyes, Angelica; O’Brien, Colin P.; Holdcroft, Steven; Pintauro, Peter; Bahar, Bamdad; Hickner, Michael; Bae, Chulsung; Sinton, David; Sargent, Edward H.; Berlinguette, Curtis P.New technologies are required to electrocatalytically convert carbon dioxide (CO2) into fuels and chemicals at near-ambient temperatures and pressures more effectively. One particular challenge is mediating the electrochemical CO2 reduction reaction (CO2RR) at low cell voltages while maintaining high conversion efficiencies. Anion exchange membranes (AEMs) in zero-gap reactors offer promise in this direction; however, there remain substantial obstacles to be overcome in tailoring the membranes and other cell components to the requirements of CO2RR systems. Here we review recent advances, and remaining challenges, in AEM materials and devices for CO2RR. We discuss the principles underpinning AEM operation and the properties desired for CO2RR, in addition to reviewing state-of-the-art AEMs in CO2 electrolysers. We close with future design strategies to minimize product crossover, improve mechanical and chemical stability, and overcome the energy losses associated with the use of AEMs for CO2RR systems.Item Dopant-tuned stabilization of intermediates promotes electrosynthesis of valuable C3 products(Nature Research, 2019-10-22) Zhuang, Tao-Tao; Nam, Dae-Hyun; Wang, Ziyun; Li, Hui-Hui; Gabardo, Christine M.; Li, Yi; Liang, Zhi-Qin; Li, Jun; Liu, Xiao-Jing; Chen, Bin; Leow, Wan Ru; Wu, Rui; Wang, Xue; Li, Fengwang; Lum, Yanwei; Wicks, Joshua; O'Brien, Colin P.; Peng, Tao; Ip, Alexander H.; Sham, Tsun-Kong; Yu, Shu-Hong; Sinton, David; Sargent, Edward H.The upgrading of CO2/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. Substantial progress has been made to improve performance at the cathodic side; whereas less progress has been made on improving anodic electro-oxidation reactions to generate value. Here we report the efficient electroproduction of value-added multi-carbon dimethyl carbonate (DMC) from CO and methanol via oxidative carbonylation. We find that, compared to pure palladium controls, boron-doped palladium (Pd-B) tunes the binding strength of intermediates along this reaction pathway and favors DMC formation. We implement this doping strategy and report the selective electrosynthesis of DMC experimentally. We achieve a DMC Faradaic efficiency of 83 ± 5%, fully a 3x increase in performance compared to the corresponding pure Pd electrocatalyst.Item Downstream of the CO2 Electrolyzer: Assessing the Energy Intensity of Product Separation(ACS, 2021-12-10) Alerte, Théo; Edwards, Jonathan P.; Gabardo, Christine M.; O’Brien, Colin P.; Gaona, Adriana; Wicks, Joshua; Obradović, Ana; Sarkar, Amitava; Jaffer, Shaffiq A.; MacLean, Heather L.; Sinton, David; Sargent, Edward H.The electrochemical reduction of carbon dioxide (CO2RR) to chemical feedstocks, such as ethylene (C2H4), is an attractive means to mitigate emissions and store intermittent renewable electricity. Much research has focused on improving CO2 electrolysis cell efficiency; less attention has been paid to the downstream purification of outlet product streams. In this work, we model the use of mature downstream separation technologies as part of the overall production of polymer-grade C2H4 from CO2. We find that CO2 removal is the most energy intensive downstream separation step. We identify opportunities to reduce separation energies to ~22 GJ/tonne C2H4 through necessary improvements in C2H4 selectivity (>57%), cathodic CO2 conversion (>80%), and CO2 crossover (0 mol CO2/mol e-). This work highlights the influence of cell performance parameters on downstream separation costs, and motivates the development of new, efficient separation processes better suited to the distinctive outlet streams of CO2 electrolyzers.Item Efficient electrically powered CO2-to-ethanol via suppression of deoxygenation(Nature Research, 2020-05-11) Wang, Xue; Wang, Ziyun; García de Arquer, F. Pelayo; Dinh, Cao-Thang; Ozden, Adnan; Li, Yuguang C.; Nam, Dae-Hyun; Li, Jun; Liu, Yi-Sheng; Wicks, Joshua; Chen, Zitao; Chi, Miaofang; Chen, Bin; Wang, Ying; Tam, Jason; Howe, Jane Y.; Proppe, Andrew; Todorović, Petar; Li, Fengwang; Zhuang, Tao-Tao; Gabardo, Christine M.; Kirmani, Ahmad R.; McCallum, Christopher; Hung, Sung-Fu; Lum, Yanwei; Luo, Mingchuan; Min, Yimeng; Xu, Aoni; O’Brien, Colin P.; Stephen, Bello; Sun, Bin; Ip, Alexander H.; Richter, Lee J.; Kelley, Shana O.; Sinton, David; Sargent, Edward H.The carbon dioxide electroreduction reaction (CO2RR) provides ways to produce ethanol but its Faradaic efficiency could be further improved, especially in CO2RR studies reported at a total current density exceeding 10 mA cm−2. Here we report a class of catalysts that achieve an ethanol Faradaic efficiency of (52 ± 1)% and an ethanol cathodic energy efficiency of 31%. We exploit the fact that suppression of the deoxygenation of the intermediate HOCCH* to ethylene promotes ethanol production, and hence that confinement using capping layers having strong electron-donating ability on active catalysts promotes C–C coupling and increases the reaction energy of HOCCH* deoxygenation. Thus, we have developed an electrocatalyst with confined reaction volume by coating Cu catalysts with nitrogen-doped carbon. Spectroscopy suggests that the strong electron-donating ability and confinement of the nitrogen-doped carbon layers leads to the observed pronounced selectivity towards ethanol.Item Efficient electrocatalytic conversion of carbon dioxide in a low-resistance pressurized alkaline electrolyzer(Elsevier, 2019-12-23) Edwards, Jonathan P.; Xu, Yi; Gabardo, Christine M.; Dinh, Cao-Thang; Li, Jun; Qi, ZhenBang; Ozden, Adnan; Sargent, Edward H.; Sinton, DavidElectrochemical carbon dioxide conversion offers a means to utilize carbon dioxide and simultaneously store excess renewable energy. To be economical, industrial carbon dioxide electroreduction systems require high energy efficiencies to minimize electrical input. To this end, these systems need high product selectivity at low cell voltages and industrially viable current densities. Here, a liquid phase flow cell electrolyzer using a silver catalyst for carbon dioxide conversion to carbon monoxide is reported. Significant improvements in cell efficiency are demonstrated through the synergistic combination of three factors: minimal electrode spacing (0.25 mm flow field), pressurization (50 bar), and alkalinity (5 M KOH). Diminished electrode spacings reduce ohmic losses, pressurization increases carbon monoxide selectivities, and alkaline conditions improve reaction kinetics. The combination of these three factors enables an uncorrected full cell energy efficiency of 67% at 202 mA/cm2, the highest reported above 150 mA/cm2. This system maintains a competitive energy efficiency of 47% at a high current density of 941 mA/cm2.Item Efficient electrosynthesis of n-propanol from carbon monoxide using a Ag–Ru–Cu catalyst(Nature Research, 2022-02-10) Wang, Xue; Ou, Pengfei; Ozden, Adnan; Hung, Sung-Fu; Tam, Jason; Gabardo, Christine M.; Howe, Jane Y.; Sisler, Jared; Bertens, Koen; García de Arquer, F. Pelayo; Miao, Rui Kai; O’Brien, Colin P.; Wang, Ziyun; Abed, Jehad; Rasouli, Armin Sedighian; Sun, Mengjia; Ip, Alexander H.; Sinton, David; Sargent, Edward H.The high-energy-density C3 fuel n-propanol is desired from CO2/CO electroreduction, as evidenced by propanol’s high market price per tonne (approximately US$ 1,400–1,600). However, CO electroreduction to n-propanol has shown low selectivity, limited production rates and poor stability. Here we report catalysts, identified using computational screening, that simultaneously facilitate multiple carbon–carbon coupling, stabilize C2 intermediates and promote CO adsorption, all leading to improved n-propanol electrosynthesis. Experimentally we construct the predicted optimal electrocatalyst based on silver–ruthenium co-doped copper. We achieve, at 300 mA cm−2, a high n-propanol Faradaic efficiency of 36% ± 3%, a C2+ Faradaic efficiency of 93% and single-pass CO conversion of 85%. The system exhibits 100 h stable n-propanol electrosynthesis. Technoeconomic analysis based on the performance of the pilot system projects profitability.Item Electroosmotic flow steers neutral products and enables concentrated ethanol electroproduction from CO2(Elsevier, 2021-10-20) Miao, Rui Kai; Xu, Yi; Ozden, Adnan; Robb, Anthony; O’Brien, Colin P.; Gabardo, Christine M.; Lee, Geonhui; Edwards, Jonathan P.; Huang, Jianan Erick; Fan, Mengyang; Wang, Xue; Liu, Shijie; Yan, Yu; Sargent, Edward H.; Sinton, DavidElectrochemical reduction of carbon dioxide (CO2RR) converts intermittent renewable energy into high energy density fuels, such as ethanol. Membrane electrode assembly (MEA) electrolyzers are particularly well-suited to CO2-to-ethanol conversion in view of their low ohmic resistance and high stability. However, over 75% of the ethanol produced at the cathode migrates through the membrane where it is diluted by the anolyte and may be oxidized. The ethanol concentration that results is two orders of magnitude below the 10 wt% standard set by the incumbent industrial process, fermentation. Here, we reverse the direction of ion and electroosmotic transport by means of a porous proton exchange layer, and thereby block both the convective and diffusive routes of ethanol loss. With this strategy, we eliminate ethanol crossover to the anode (< 1%), and achieve an ethanol concentration of 13.1 wt% directly from the cathode outlet.Item A microchanneled solid electrolyte for carbon-efficient CO2 electrolysis(Elsevier (Science Direct), 2022-06-15) Xu, Yi; Miao, Rui Kai; Edwards, Jonathan P.; Liu, Shijie; O’Brien, Colin P.; Gabardo, Christine M.; Fan, Mengyang; Huang, Jianan Erick; Robb, Anthony; Sargent, Edward H.; Sinton, DavidThe electrochemical reduction of CO2 is a promising route to convert carbon emissions into valuable chemicals and fuels. In electrolyzers producing multi-carbon products, 70%–95% of the supplied CO2 is converted to (bi)carbonates, limiting the carbon efficiency of electrochemical CO2 conversion. These (bi)carbonate anions can be lost to the aqueous electrolyte, converted back to gaseous CO2 and diluted in the anode tail gas, and/or combined with alkali metal cations from the electrolyte to form solid salt precipitates. Here, we report a microchanneled solid electrolyte that allows for the recapture and recycling of (bi)carbonate ions before reaching the anode, reducing CO2 loss to ∼3%. We demonstrate CO2 electroreduction to multi-carbon products with 77% selectivity without the use of alkali metal cations, by incorporating fixed quaternary ammonium cations. This system simultaneously achieves near-zero CO2 loss, high selectivity toward multi-carbon products, and stable operation at an industrially relevant current density over 200 h.Item Oxygen-Tolerant Electroproduction of C2 Products from Simulated Flue Gas(The Royal Society of Chemistry, 2019-12-23) Xu, Yi; Edwards, Jonathan P.; Zhong, Junjie; O'Brien, Colin P.; Gabardo, Christine M.; McCallum, Christopher; Li, Jun; Dinh, Cao-Thang; Sargent, Edward H.; Sinton, DavidThe electroreduction of carbon dioxide (CO2) to C2 products is a promising approach to divert and utilize CO2 emissions. However, the requirement of a purified CO2 feedstock decreases the economic feasibility of CO2 electrolysis. Direct utilization of industrial flue gas streams is encumbered by low CO2 concentrations and reactive oxygen (O2) impurities. We demonstrate that pressurization enables efficient CO2 electroreduction of dilute CO2 streams (15% v/v); however, with the inclusion of O2 (4% v/v), the oxygen reduction reaction (ORR) displaces CO2 reduction and consumes up to 99% of the applied current in systems based on previously-reported catalysts. We develop a hydrated ionomer catalyst coating strategy that selectively slows O2 transport and stabilizes the copper catalyst. Applying this strategy, we convert an O2-containing flue gas to C2 products at a faradaic efficiency (FE) of 68% and a non-iR-corrected full cell energetic efficiency (EE) of 26%.Item Pilot-Scale CO2 Electrolysis Enables a Semi-empirical Electrolyzer Model(2023-05-11) Edwards, Jonathan P.; Alerte, Théo; O’Brien, Colin P.; Gabardo, Christine M.; Liu, Shijie; Wicks, Joshua; Gaona, Adriana; Abed, Jehad; Xiao, Yurou Celine; Young, Daniel; Sedighian Rasouli, Armin; Sarkar, Amitava; Jaffer, Shaffiq A.; MacLean, Heather L.; Sargent, Edward H.; Sinton, DavidCarbon dioxide (CO2) electrolysis powered with renewable electricity can help close the carbon cycle by converting emissions into chemicals and fuels. Two key advancements are required to bridge the technological gaps for industrial implementation: pilot plant demonstrations with detailed performance data; and chemical engineering process models built and tested with lab- and pilot-scale data. Here, we develop a semi-empirical electrolyzer model in Aspen Custom Modeler which is trained on a 5 cm2 lab-scale CO2 electrolyzer. We then scaled to a pilot-scale 800 cm2 single cell and 10 x 800 cm2 stack and use the results to validate the model; at 100 mA cm-2, the model can predict six of seven cell performance metrics within 16% absolute error and three of five stack metrics within 11% absolute error. With the combination of the electrolyzer model and the pilot-scale data, this work provides the perquisites for further scaling of CO2 electrolysis.Item Self-Cleaning CO2 Reduction Systems: Unsteady Electrochemical Forcing Enables Stability(ACS Publications, 2021-02-02) Xu, Yi; Edwards, Jonathan P.; Liu, Shijie; Miao, Rui Kai; Huang, Jianan Erick; Gabardo, Christine M.; O’Brien, Colin P.; Li, Jun; Sargent, Edward H.; Sinton, DavidThe electrochemical conversion of CO2 produces valuable chemicals and fuels. However, operating at high reaction rates produces locally alkaline conditions that convert reactant CO2 into cell-damaging carbonate salts. These salts precipitate in the porous cathode structure, block CO2 transport, reduce reaction efficiency, and render CO2 electrolysis inherently unstable. We propose a self-cleaning CO2 reduction strategy with short, periodic reductions in applied voltage, which avoids saturation and prevents carbonate salt formation. We demonstrate this approach in a membrane electrode assembly (MEA) with silver and copper catalysts, on carbon and polytetrafluoroethylene (PTFE)-based gas diffusion electrodes, respectively. When operated continuously, the C2 selectivity of the copper–PTFE system started to decline rapidly after only ∼10 h. With the self-cleaning strategy, the same electrode operated for 157 h (236 h total duration), maintaining 80% C2 product selectivity and 138 mA cm–2 of C2 partial current density, at a cost of <1% additional energy input.Item Single Pass CO2 Conversion Exceeding 85% in the Electrosynthesis of Multicarbon Products via Local CO2 Regeneration(ACS Publications, 2021-07-30) O’Brien, Colin P.; Miao, Rui Kai; Liu, Shijie; Xu, Yi; Lee, Geonhui; Robb, Anthony; Huang, Jianan Erick; Xie, Ke; Bertens, Koen; Gabardo, Christine M.; Edwards, Jonathan P.; Dinh, Cao-Thang; Sargent, Edward H.; Sinton, DavidThe carbon dioxide reduction reaction (CO2RR) presents the opportunity to consume CO2 and produce desirable products. However, the alkaline conditions required for productive CO2RR result in the bulk of input CO2 being lost to bicarbonate and carbonate. This loss imposes a 25% limit on the conversion of CO2 to multicarbon (C2+) products for systems that use anions as the charge carrier – and overcoming this limit is a challenge of singular importance to the field. Here we find that cation exchange membranes (CEMs) do not provide the required locally alkaline conditions; and bipolar membranes (BPMs) are unstable, delaminating at the membrane-membrane interface. We develop a permeable CO2 regeneration layer (PCRL) that provides an alkaline environment at the CO2RR catalyst surface and enables local CO2 regeneration. With the PCRL strategy, CO2 crossover is limited to 15% of the amount of CO2 converted into products, in all cases. Low crossover and low flowrate combine to enable a single pass CO2 conversion of 85% (at 100 mA/cm2), with a C2+ faradaic efficiency and full cell voltage comparable to the anion-conducting membrane electrode assembly.