22 research outputs found
Rapid screening of CO2 capture fluids
No full textThe evaluation of CO2 capture fluids is crucial for the advancement of carbon capture technologies. Recent advancements in amine-based carbon capture fluids motivate a broad search for high-performance fluids and the development of methods capable of exploring a large chemical space. Here, we present a microfluidic approach paired with automated image processing and density functional theory simulations that enables comprehensive rapid screening of capture fluids. The principle of measurement leverages the ability to monitor phase expansion and contraction in fixed-volume dead-end channels. This approach enables fast comparative assessments of reaction kinetics and thermodynamic parameters, including CO2 absorption rate (∼30 s), desorption rate (∼30 s), absorption capacity (∼20 min), and vapor pressure (∼5 min), exceeding the speed of conventional methods by two orders of magnitude. The method is broadly applicable, effective for primary, secondary, and tertiary amine types. Rapid screening of capture fluids holds promise for the accelerated discovery of improved CO2 capture processes and an opportunity for the microfluidics community to contribute to decarbonization efforts.The authors would like to express their sincere gratitude for the financial backing provided by the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canada Research Chairs Program (CRC-2021-00316)
High-throughput parallelized testing of membrane electrode assemblies for CO2 reduction
No full textThe authors acknowledge the early-stage contribution of Dr. Jonathan P. Edwards in the system design. The authors also acknowledge support from The Alliance for AI-Accelerated Materials discovery (A3MD), which includes funding from Total Energies SE., Microsoft, and LG AI Research. This work was supported by the Vanier Canada Graduate Scholarship. © The Royal Society of Chemistry 2022High-throughput characterization of electrochemical reactions can accelerate discovery and optimization cycles, and provide the data required for further acceleration via machine-learning guided experiment planning. There are a range of high-throughput methods available for catalyst discovery. However, the development and testing of electrochemical systems – integrated electrocatalysts, membranes, and electrodes – currently relies on serial, labor-intensive lab processes. Membrane electrode assembly (MEA) cells have shown particular promise in carbon dioxide (CO2) reduction, providing commercially viable reaction rates. Experimental testing of MEAs is slow, requiring a serial assembly process that can result in electrode compression levels that are non-uniform over the cell area and challenging to reproduce. Here we demonstrate a new MEA testing system that offers an accelerated, parallelized assembly process and enables high-throughput electrochemical system testing. The approach accelerates electrochemical system testing, controls compression and improves repeatability and reliability. We benchmark our system with CO2 reduction to ethylene, running 10 MEA experiments in parallel, demonstrating an acceleration factor up to 12× over conventional approaches, and achieving a cell-to-cell gas selectivity deviation of ±2.5%
Regeneration of direct air CO2 capture liquid via alternating electrocatalysis
No full textThe direct air capture (DAC) of carbon dioxide (CO2) can potentially contribute to mitigating past and offsetting hard-to-abate future emissions; however, the regeneration of DAC capture liquids requires high temperatures and thermal energy inputs with emissions that diminish their net environmental benefit. Here, we present a low-temperature electrochemical process to regenerate alkaline capture liquids via alternating electrocatalysis (AE). Colocating oxidation and reduction reactions on a single electrode, cycled between electrolyzer and fuel cell modes, mitigates film formation and losses in the regeneration of alkali hydroxide and hydrogen halide. CO2 can be captured and released with an energy input of 6.4 GJ/tCO2 at 100 mA cm−2 and an emission intensity of ∼11 kg CO2e/tCO2.The authors acknowledge support from the Natural Sciences and Engineering Research Council (NSERC) of Canada and Natural Resources Canada—Clean Growth Program. Y.X. acknowledges NSERC for their support in the form of a Banting postdoctoral fellowship. Y.C.X. thanks Hatch for their support through graduate scholarship
Industrial amine blends enable efficient CO electrosynthesis in reactive capture
No full textReactive capture of CO2 (RCC) integrates CO2 capture and electrochemical conversion into carbon monoxide (CO), avoiding the energy-intensive CO2 regeneration required in conventional CO2 electrolysis. While single-component amines have been used in prior RCC systems, they suffer from limited CO energy efficiency (<15%) due to sluggish CO2 release. In contrast, the norm in industrial CO2 capture is to blend amines for a favorable combination of absorption rate, CO2 loading capacity, and release energetics. Here, we explore whether blending amines could likewise benefit reactive capture. Using aqueous blends of monoethanolamine (MEA) and methyldiethanolamine (MDEA), we find a strong correlation between bicarbonate concentration in the post-capture solution and CO faradaic efficiency (FE). However, under industrial absorption conditions, the blend with the highest bicarbonate content did not always yield the best CO FE: although MDEA increased bicarbonate concentrations, it also increased the viscosity, hindering CO2 mass transport and increasing cell resistance. These competing effects highlight that, for efficient RCC, the composition must balance CO2 absorption kinetics and capacity for capture, as well as CO2 availability and transport properties for conversion. Screening the performance of binary and commercial amine blends, we find a CO energy efficiency (EE) of 31% at 50 mA cm−2—a 2.4-fold improvement over single-amine systems.We gratefully acknowledge support from Shell Global Solutions International B.V., the Canada Research Chairs Program (CRC-2021-00316), and the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Alliance Program and the Discovery Program, as well as Gaussian Inc., Compute Ontario (https://www.computeontario.ca) and the Digital Research Alliance of Canada (https://www.alliancecan.ca). S. S. S. thanks the Government of Ontario for their support through graduate scholarships. Y. C. X. thanks NSERC and Hatch for their support through graduate scholarships
Scaled CO Electroreduction to Alcohols
No full textElectrocatalysis offers a promising route to convert CO2 into alcohols, which is most efficient in a two-step cascade reaction with CO2-to-CO followed by CO-to-alcohol. However, current alcohol-producing CO2/CO electrolyzers suffer from low selectivity or alcohol crossover, resulting in alcohol concentrations of less than 1%, which are further diluted in downstream cold traps. As a result, electrocatalytic alcohol production has yet to be scaled beyond the lab (1-10cm2).Here, we reverse the electroosmotic drag of water using a cation exchange membrane assembly, enabling the recovery of over 85% of alcohol products at a concentration of 6 wt%.We develop a multi-step condenser strategy to separate the produced alcohols from the effluent gas stream without dilution. Scaling up this approach to an 800cm2cell–currently the largest single CO2/CO electrolyzer to date–resulted in an output of 200 mLalcohol/day.The authors acknowledge funding for this work from the Government of Canada’s New Frontiers in Research Fund (NFRF), CANSTOREnergyproject NFRFT-2022-00197. This work also received financial support from the Natural Sciences and Engineering Research Council of Canada 371(NSERC)
Pilot-Scale CO2 Electrolysis Enables a Semi-empirical Electrolyzer Model
No full textThis document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Energy Letters, copyright © 2023 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/full/10.1021/acsenergylett.3c00620.Carbon 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.The authors acknowledge financial support from the Natural Sciences and Engineering Research Council (NSERC) of Canada, TotalEnergies SE (TotalEnergies Research & Technology Feluy (an affiliate of TotalEnergies SE, France), the University of Toronto, the Ontario Centre of Innovation (OCI), and the Natural Resources Canada Clean Growth Program. D.S. gratefully acknowledges support from the Canada Research Chairs Program. The authors thank the XPRIZE Foundation, NRG COSIA, and the Alberta Carbon Conversion Technology Center (ACCTC) for their support of carbon utilization technologies
CO2 electroreduction to multicarbon products from carbonate capture liquid
No full textAlkali hydroxide systems capture CO 2 as carbonate; however,
generating a pure CO 2 stream requires significant energy input,
typically from thermal cycling to 900 C. What is more, the subse-
quent valorization of gas-phase CO 2 into products presents addi-
tional energy requirements and system complexities, including man-
aging the formation of (bi)carbonate in an electrolyte and
separating unreacted CO 2 downstream. Here, we report the direct
electrochemical conversion of CO 2 , captured in the form of carbon-
ate, into multicarbon (C 2+ ) products. Using an interposer and a Cu/
CoPc-CNTs electrocatalyst, we achieve 47% C 2+ Faradaic efficiency
at 300 mA cm 2 and a full cell voltage of 4.1 V. We report 56 wt % of
C 2 H 4 and no detectable C 1 gas in the product gas stream: CO, CH 4 ,
and CO 2 combined total below 0.9 wt % (0.1 vol %). This approach
obviates the need for energy to regenerate lost CO 2 , an issue
seen in prior CO 2 -to-C 2+ reports
Improving the SO2 tolerance of CO2 reduction electrocatalysts using a polymer:catalyst:ionomer heterojunction design
No full textThis work was financially supported by the National Key Research and Development Program of China (2022YFA1505100 and 2023YFA1507500 to J.L.), the National Natural Science Foundation of China (grant number BE3250011 to J.L.), the Fundamental Research Funds for the Central Universities (23X010301599 to J.L.), Shanghai Pilot Program for Basic Research - Shanghai Jiao Tong University (21TQ1400227 to J.L.), the Ontario Research Foundation: Research Excellence Program to D.S., the Natural Sciences and Engineering Research Council (NSERC) of Canada to D.S and P.P., and TOTAL SE to D.S.. Part or all of the XAS measurements described in this paper were performed at the Soft X-ray Microcharacterization Beamline (SXRMB) at the Canadian Light Source, a national research facility of the University of Saskatchewan, which is supported by NSERC, the Canada Foundation for Innovation (CFI), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan. Support from Canada Research Chairs Program is gratefully acknowledged. The computational study is supported by the Marsden Fund Council from Government funding (21-UOA-237 to Z.W.) and Catalyst: Seeding General Grant (22-UOA-031-CGS to Z.W.), managed by Royal Society Te Apārangi. Z.W. and R.L. wish to acknowledge the use of New Zealand eScience Infrastructure (NeSI) high performance computing facilities, consulting support and/or training services as part of this research
Scale-Dependent Techno-Economic Analysis of CO2 Capture and Electroreduction to Ethylene
No full textThe decarbonization of the chemical industry is essential
to mitigate
carbon dioxide (CO2) emissions. Ethylene (C2H4) is the highest production petrochemical globally.
When powered by renewable electricity, the electrochemical conversion
of CO2 to C2H4 offers a promising
route to low carbon C2H4 production. We perform
a detailed techno-economic assessment (TEA) of the CO2 reduction
reaction (CO2RR) process, converting CO2 from
an industrial point source to polymer-grade C2H4. We pair the CO2 electrolyzer with industrially mature
upstream and downstream separation technologies in an Aspen Plus model.
This comprehensive approach enables us to assess the valorization
of both gas and liquid byproduct streams at commercial specification
and assess the viability of these processes as a function of scale.
We demonstrate that a minimum plant size of ∼3,000 tonne C2H4/year is needed to achieve economies of scale
among the upstream and downstream processes. This minimum plant size
is ∼200-fold smaller than that of conventional C2H4 plants, coincides with that of typical utility-scale
solar installations (∼25 MW), and could enable a more distributed
model of chemical production going forward. We further highlight technical
and economic enablers that would increase the profitability of the
CO2RR to C2H4 technology
