Chemie Research Articles

Intrinsic Catalytic Activity and Active Phase for Oxygen Evolution in Layered Double Hydroxide Electrocatalysts

The NiFe layered double hydroxides (LDHs) are among the most active electrocatalysts for the oxygen evolution reaction (OER) in alkaline electrolytes.1 The incorporation of Fe dramatically increases the catalytic activity of Ni hydroxides.2 However, even the most active NiFe LDH catalyst still shows a considerable overpotential for the OER. Understanding the nature of the catalytic active sites and the catalytic mechanism are key challenges to develop better OER electrocatalysts.In this contribution, atomic-scale details of the catalytic active phase will be presented, showing that NiFe LDHs are oxidized under applied anodic potentials from as-prepared α-phases to activated γ-phases.3 The interlayer and in-plane lattice parameters of the OER-active γ-phase were obtained by performing wide angle X-ray scattering (WAXS) measurements on NiFe LDH nanoplatelets during operating electrochemical conditions and were characterized by a contraction of about 8%. Operando WAXS was then performed for other selected catalysts belonging to the transition metal LDH family of materials. Structural similarities of the catalytically active phases will be highlighted.Finally, in order to derive activity-structure relationships, an approach is presented to calculate intrinsic catalytic activities, which are challenging to evaluate for this class of materials. The presented method is based on electrochemical active surface area normalization obtained by impedance spectroscopy measurements under OER.4 References F. Dionigi and P. Strasser, Advanced Energy Materials, 2016, 6 1600621. L. Trotochaud, S. L. Young, J. K. Ranney and S. W. Boettcher, Journal of the American Chemical Society, 2014, 136: 6744-6753.F. Dionigi, Z. Zeng, I. Sinev, T. Merzdorf, S. Deshpande, M. B. Lopez, S. Kunze, I. Zegkinoglou, H. Sarodnik, D. Fan, A. Bergmann, J. Drnec, J. Ferreira de Araujo, M. Gliech, D. Teschner, J. Zhu, W.-X. Li, J. Greeley, B. Roldan Cuenya and P. Strasser, Nat Commun, 2020, 11 2522.F. Dionigi, J. Zhu, Z. Zeng, T. Merzdorf, H. Sarodnik, M. Gliech, L. Pan, W.-X. , Li, J. Greeley, and P. Strasser, Angew Chem Int Edit, 60, 14446 – 14457 (2021).

Biocatalysis tips another domino: A single-enzyme Enders triple cascade reaction

Multi-enzyme cascades are increasingly popular, but single-enzyme cascades, which avoid issues of catalyst compatibility, are still rare. A new article by Melchiorre and co-workers in Angewandte Chemie describes the design and engineering of an enzyme capable of catalyzing the Enders triple cascade reaction, resulting in four new stereocenters. Multi-enzyme cascades are increasingly popular, but single-enzyme cascades, which avoid issues of catalyst compatibility, are still rare. A new article by Melchiorre and co-workers in Angewandte Chemie describes the design and engineering of an enzyme capable of catalyzing the Enders triple cascade reaction, resulting in four new stereocenters.

Graphical Abstract: Angew. Chem. Int. Ed. 40/2022

Angewandte Chemie International EditionVolume 61, Issue 40 e202284011 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 40/2022 First published: 26 September 2022 https://doi.org/10.1002/anie.202284011AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume61, Issue40October 4, 2022e202284011 RelatedInformation

Graphical Abstract: Angew. Chem. Int. Ed. 39/2022

Angewandte Chemie International EditionVolume 61, Issue 39 e202283911 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 39/2022 First published: 19 September 2022 https://doi.org/10.1002/anie.202283911AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume61, Issue39September 26, 2022e202283911 RelatedInformation

Graphisches Inhaltsverzeichnis: Angew. Chem. 38/2022

Angewandte ChemieVolume 134, Issue 38 e202283811 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 38/2022 First published: 12 September 2022 https://doi.org/10.1002/ange.202283811AboutPDF ToolsRequest permissionAdd to favorites ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume134, Issue38September 19, 2022e202283811 This is the German version of Angewandte Chemie. Note for articles published since 1962: Do not cite this version alone. Take me to the International Edition version with citable page numbers, DOI, and citation export. We apologize for the inconvenience. RelatedInformation

Zurückziehung: Inorganic Chiral Hybrid Nanostructures for Tailored Chiroptics and Chirality‐Dependent Photocatalysis

The above article from Angewandte Chemie, published online on 22 December 2021 in Wiley Online Library (wileyonlinelibrary.com, DOI: 10.1002/ange.202112400), and in print in Volume 134, e202112400, has been retracted by agreement between the authors, the journal′s Executive Committee, and Wiley-VCH GmbH, Weinheim. The retraction has been agreed upon following an explanation by the authors that part of the data presented in the article was not authorized for publication.

Graphical Abstract: Angew. Chem. Int. Ed. 35/2022

Angewandte Chemie International EditionVolume 61, Issue 35 e202283511 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 35/2022 First published: 20 August 2022 https://doi.org/10.1002/anie.202283511AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume61, Issue35August 26, 2022e202283511 RelatedInformation

Give crucibles to a prokaryote

Prokaryotes are hodgepodge-like "bags" with minimal intracellular organization. Recently in <i>Angewandte Chemie International Edition</i>, Xia et al. synthesized artificial membraneless organelles in prokaryotes as "crucibles" for enhanced biosynthesis of terpene, driven by liquid-liquid phase separation of engineered intrinsically disordered proteins.

Graphical Abstract: Angew. Chem. Int. Ed. 31/2022

Angewandte Chemie International EditionVolume 61, Issue 31 e202283111 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 31/2022 First published: 25 July 2022 https://doi.org/10.1002/anie.202283111AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume61, Issue31August 1, 2022e202283111 RelatedInformation

Graphical Abstract: Angew. Chem. Int. Ed. 29/2022

Angewandte Chemie International EditionVolume 61, Issue 29 e202282911 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 29/2022 First published: 11 July 2022 https://doi.org/10.1002/anie.202282911AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume61, Issue29July 18, 2022e202282911 RelatedInformation

Handling the Carbonates: Interfacial Engineering of Garnet Electrolytes

Since Murugan et al. [1] discovered the Li7La3Zr2O12 (LLZO) inorganic solid state electrolyte composition, extensive work has been devoted to understanding its behavior and optimizing its structural and compositional features. Although improvement of its bulk and composition has allowed reaching ionic conductivities roughly in the range of mS/cm, much more work is needed in terms of assembling actual all-solid-state batteries by using this material.In this work, we aim at a two fold improvement of the LLZO surface contact with the electrodes by not only creating a new layer on the surface of this ceramic electrolyte, but also by converting the non-conductive lithium carbonate layer [2] that forms on the LLZO surface upon air exposure. Through this rational approach, we expect a chemically relevant surface transformation, linked to a change in the electrochemical performance, via facilitation of the ionic transport through the surface of the ceramic pellet and an improved interface contact. LLZO pellets are treated with boric acid [3] in order to form borate species on their surface, substituting totally or partially the carbonate species that hinder ionic conductivity on the surface. The influence of both atmosphericexposure, treatment and stirring on the resulting pellets is tracked via Raman, XPS and XRD analyses to obtain a comparison and assess the impact of these factors. The final effect of the boric acid treatment is checked via SEM-EDX and electrochemical impedance spectroscopy (EIS) analyses, to determine both morphological and electrochemical effects of the surface modification, which will further influence the interfacial characteristics of the pellet with both electrodes, with a special focus on the lithium side. Our results show an improvement of the surface properties of the pellets, due to the morphological and chemical modification of the LLZO surface, withoutaffecting the bulk properties. [1] Ramaswamy Murugan, Venkataraman Thangadurai, and Werner Weppner. “Fast lithium ion conduction in garnet-type Li7La 3Zr2O12”. In: Angewandte Chemie - International Edition 46.41 (2007), pp. 7778–7781. issn: 14337851. doi: 10.1002/anie.200701144. [2] Asma Sharafi et al. “Impact of air exposure and surface chemistry on Li-Li7La3Zr2O12 interfacial resistance”. In: Journal of Materials Chemistry A 5.26 (2017), pp. 13475–13487. issn: 20507496. doi: 10.1039/c7ta03162a. [3] Yadong Ruan et al. “Acid induced conversion towards a robust and lithiophilic interface for Li-Li7La3Zr2O12 solid-state batteries”. In: Journal of Materials Chemistry A 7.24 (2019), pp. 14565–14574. issn: 20507496. doi: 10.1039/c9ta01911a. Figure 1

Developing New Quinone Based Electrodes for Electrochemical Carbon Capture

The need for cost-effective carbon capture technology is rapidly increasing. To limit the global temperature increase to 1.5 degrees within the next century, the level of CO2 mitigation needs to be increased drastically [1]. Current technology, i.e., amine scrubbing, provides several challenges which limit their deployment: high regeneration energy, high operational costs and degradation at high temperatures [2]. An electrochemical approach avoids large energy losses and can selectively uptake CO2 by utilizing redox-active organic molecules. To compete with conventional chemical scrubbing, the electrochemical cell needs high power density, high CO2 uptake and long cycle stability. Redox-active molecules such as quinone-based molecules have been utilized in this area however suffer from low cycling stability due to organic molecules leaking into the electrolyte [3,4]. Quinone-polymer electrodes have shown a high efficiency for CO2 capture however are prone to quinone degradation and low active-material mass [5]. Here we present our work on a new class of quinone-based electrodes for electrochemical CO2 capture, and explore their electrochemistry in the presence and absence of CO2 and quantify their CO2 uptake capacities. This work paves the way for the design and discovery of improved electrode materials for electrochemical CO2 capture. The Intergovernmental Panel on Climate Change (2018), Global Warming of 1.5 degrees. Available at: https://www.ipcc.ch/sr15/ (Accessed: 10 December 2021)Rahimi, M., Zucchelli, F., Puccini, M. and Alan Hatton, T., 2020. Improved CO2 Capture Performance of Electrochemically Mediated Amine Regeneration Processes with Ionic Surfactant Additives. ACS Applied Energy Materials, 3(11), pp.10823-10830.Apaydin, D., Głowacki, E., Portenkirchner, E. and Sariciftci, N., 2014. Direct Electrochemical Capture and Release of Carbon Dioxide Using an Industrial Organic Pigment: Quinacridone. Angewandte Chemie International Edition, 53(26), pp.6819-6822.Ranjan, R., Olson, J., Singh, P., Lorance, E., Buttry, D. and Gould, I., 2015. Reversible Electrochemical Trapping of Carbon Dioxide Using 4,4′-Bipyridine That Does Not Require Thermal Activation. The Journal of Physical Chemistry Letters, 6(24), pp.4943-4946.Voskian, S and Hatton, T., 2019. Faradaic Electro-swing Reactive Adsorption for CO2 Capture. Energy and Environmental Science, 12(12), pp.3530-3547

Size and Charge Effects on Organic Flow Battery Crossover Evaluated By Quinone Permeabilities through Nafion

Organic and metalorganic reactants have become promising for long-lifetime flow batteries. Synthetic chemistry unlocks a wide design space to tailor reactant redox potential, solubility, chemical and electrochemical stability, redox kinetics, and transport properties. Minimizing the crossover of reactants through the membrane or separator is one crucial design goal. To that end, this work contributes a systematic evaluation of size- and charge-based effects on small molecule permeability through Nafion. These results inform the design of flow battery electrolytes that improve the transport selectivity of ion exchange membranes.Some recent flow battery designs have included crossover suppression strategies based on size and charge of reactants. One option is to leverage size-exclusion, for example by tethering redox-active moieties to polymer backbones,1,2 or by oligomerizing redox-active monomers.3-5 A charge-based strategy has been employed to decrease viologen crossover: sulfonate6 or phosphonate7 solubilizing groups were attached to the redox active core and paired with a cation exchange membrane, reducing crossover compared to previous iterations of this chemistry. Crossover rates of some organic-based flow battery molecules have been estimated to be very low, but other considerations must be balanced for designing viable battery technology. For example, electrolyte cost and solubility may be in direct tension with a crossover suppression strategy based on increasing redox mediator size.8 Untangling the effects of different membrane-molecule selectivity mechanisms is a valuable step on the path to advancing redox active molecule design.This work evaluates a set of quinones in which size is varied by the number of aromatic rings (e.g. hydroquinone, anthraquinone) and charge number is varied almost independently through sulfonation. Each sulfonate moiety contributes a -1 charge, increasing the magnitude of the molecule charge number with the same sign as the fixed charges in Nafion. Effective size of solvated species is accessed through rotating disk electrode voltammetry: Stokes radii are calculated from measured diffusion coefficients. We found over an order of magnitude permeability reduction per sulfonate, emphasizing the importance of charge-based exclusion for ion exchange membranes. In comparison, size-exclusion effects are less impactful. For example, the Stokes radius of anthraquinone 2,6-disulfonate (AQDS) is twice that of hydroquinone 2,5-disulfonate but their permeabilities fall within the same order of magnitude.1. T. Hagemann, J. Winsberg, M. Grube, I. Nischang, T. Janoschka, N. Martin, M. D. Hager, and U. S. Schubert, Journal of Power Sources, 378, 546 (2018).2. T. Janoschka, N. Martin, U. Martin, C. Friebe, S. Morgenstern, H. Hiller, M. D. Hager, and U. S. Schubert, Nature, 527, 78 (2015).3. M. J. Baran, M. N. Braten, E. C. Montoto, Z. T. Gossage, L. Ma, E. Chenard, J. S. Moore, J. Rodrıguez-Lopez, and B. A. Helms, Chemistry of Materials, 30, 3861 (2018).4. K. H. Hendriks, S. G. Robinson, M. N. Braten, C. S. Sevov, B. A. Helms, M. S. Sigman, S. D. Minteer, and M. S. Sanford, ACS Central Science, 4, 189 (2018).5. S. E. Doris, A. L. Ward, A. Baskin, P. D. Frischmann, N. Gavvalapalli, E. Chenard, C. S. Sevov, D. Prendergast, J. S. Moore, and B. A. Helms, Angewandte Chemie, 129, 1617 (2017).6. C. Debruler, B. Hu, J. Moss, J. Luo, and T. L. Liu, ACS Energy Letters, 3, 663, (2018).7. S. Jin, E. M. Fell, L. Vina-Lopez, Y. Jing, P. W. Michalak, R. G. Gordon, and M. J. Aziz, Advanced Energy Materials, 10, (2020).8. M. L. Perry, J. D. Saraidaridis, and R. M. Darling, Current Opinion in Electrochemistry, 21, 311 (2020).

Protein Corona Formation on Hard and Polymeric Nanoparticles – Towards Understanding Biocompatibility, Biodistribution, and Efficacy

Unpredictable protein adsorption on both hard and soft nanoparticles remains a considerable challenge towards effectively applying nanotechnologies in biological environments. Hard nanoparticles form the basis of many chemical nanosensors. Conversely, soft nanoparticles such as lipid nanoparticles (LNPs) are vital for the successful delivery of mRNA-based vaccines, and offer promising applications in neonatal gene therapy, immunotherapy, and protein replacement therapy. Understanding the biological interactions that both hard and soft nanoparticles undergo upon introduction into biological systems is central to optimize the outcomes of nanoparticle-based delivery biotechnologies in clinical settings.Herein, we present a multimodal study of protein corona composition and dynamics, first on ‘hard’ nanoparticles: spherical polystyrene nanoparticles (a previously studied model nanoparticle) and high aspect ratio single-walled carbon nanotubes (SWCNTs, an understudied nanoparticle). These nanoparticles are exposed to two biofluids of interest: blood plasma (relevant for intravenous applications) and cerebrospinal fluid (relevant for brain imaging and sensing applications). To study these protein coronas, we develop a methodology based on quantitative proteomic mass spectrometry [1] and chemical thermodynamic analysis of real-time protein binding to identify protein corona ‘fingerprints’, enabling quantification of protein abundance and enrichment/depletion relative to the native biofluid, transient kinetics [2], and end-state topology. Interestingly, we find that the heavily studied polystyrene nanoparticles are relatively agnostic in the formation of their protein coronas, demonstrating little preference for particular protein classes or physicochemical properties. Conversely, we find that SWCNTs show strong preference for certain protein classes. Our additional work in machine learing-based analysis shows that corona compositions, and more broadly nanoparticle biofouling, can be drastically different for each nanoparticle type [3].Lastly, we study nano-bio interactions encountered by ‘soft’ nanoparticles: LNPs commonly used for the therapeutic delivery of mRNA. We investigate how modifying (i) the mRNA packaged inside the LNPs and (ii) the ionizable lipid within the LNPs modulate the subsequently formed protein corona in (iii) various biological environments of relevance for delivery applications. Importantly, this workflow is readily translatable across soft polymer-based nanotechnologies of interest, which are understudied due to the experimental complexity of separating nanoparticle-corona complexes from free proteins. This fundamental understanding of protein-LNP interactions could enable more seamless design and clinical application of next-generation LNP carriers to bolster the safe and effective delivery of mRNA and other therapeutics to patients. References Pinals, R.L., et al., Quantitative Protein Corona Composition and Dynamics on Carbon Nanotubes in Biological Environments. Angewandte Chemie (2020).Pinals, R. L., Yang, D., Lui, A., Cao, W. & Landry, M. P. Corona Exchange Dynamics on Carbon Nanotubes by Multiplexed Fluorescence Monitoring. JACS (2020).Ouassil, N.*, Pinals, R.L.*, O’Donnell, J.T.D., Wang, J., Landry, M.P.‡ Supervised Learning Model to Predict Protein Adsorption to Nanoparticles. Science Advances (2022).

(Digital Presentation) Design of High-Performance Antimony / MXene Hybrid Electrodes for Sodium-Ion Batteries

As a result of the growing electrification and the ever-increasing demand for batteries, scarcity of fossil resources of lithium, and the resulting rise in price, energy storage technologies beyond lithium aroused high interest throughout the past years.1-3 Sodium is a naturally abundant element in the earth and therefore offers the opportunity to develop a promising low-cost, large-scale energy application with favorable energy and power densities. Recently, frequent new and further developments on the anode and cathode materials for sodium-ion batteries have been made. In particular, the development of anode material presents massive challenge while several requirements of high capacity and long lifetime/high durability need to be fulfilled.The unique properties of the novel 2D material MXene, including their excellent electrical conductivity and accessible interlayer space, enable them to be used as attractive electrode materials for battery and supercapacitor. Still, a major drawback is that the capacity of Na+-ion storage by intercalation chemistry is limited due to the limited storage sites.4 As it comes to high-capacity materials, the research field of conversion and alloying materials provides highly attractive candidates. For example, antimony is a promising anode candidate, which undergoes alloying reaction with sodium to form Na3Sb, delivering a high theoretical capacity of 660 mAh g-1. Still, the major drawback of alloying materials is the high volume changes during sodiation and de-sodiation which often leads to electrode cracking, pulverization, continuous reformation of SEI and thus results in poor electrochemical performance. It is, therefore, highly promising to combine both, MXene and antimony for stable, high performance energy storage.Our work explores the best strategy to achieve Sb/MXene hybrid electrodes. There is a tremendous influence in the electrochemical performance dependent on Sb-to-MXene ratio, Sb distribution, and Sb/MXene entanglement. The optimized performance does not align with the highest amount of antimony, the smallest nanoparticles, or the largest interlayer distance of the MXene but by the most homogeneous distribution of antimony and MXene while both components remain electrochemically addressable. With the best optimized hybrid material, we obtained electrodes showing a specific capacity of 450 mAh g-1 at 0.1 A g-1 and 365 mAh g-1 at 4 A g-1, with capacity retention of around 96% after 100 cycles. References Perveen, T.; Siddiq, M.; Shahzad, N.; Ihsan, R.; Ahmad, A.; Shahzad, M. I., Prospects in anode materials for sodium ion batteries-A review. Renewable and Sustainable Energy Reviews 2020, 119, 109549.Skundin, A.; Kulova, T.; Yaroslavtsev, A., Sodium-ion batteries (a review). Russian Journal of Electrochemistry 2018, 54 (2), 113-152.Kundu, D.; Talaie, E.; Duffort, V.; Nazar, L. F., The emerging chemistry of sodium ion batteries for electrochemical energy storage. Angewandte Chemie International Edition 2015, 54 (11), 3431-3448.Kim, Y.; Ha, K. H.; Oh, S. M.; Lee, K. T., High‐capacity anode materials for sodium‐ion batteries. Chemistry–A European Journal 2014, 20 (38), 11980-11992. Figure: De-sodiation capacity and Coulombic efficiency versus cycle number of a simple mechanical mixed antimony MXene electrode (pink) and optimized hybrid material (blue). Figure 1

High Throughput Synthesis of Perovskite Oxides for Alkaline Oxygen Evolution Reaction Electrocatalysis: Nature of the a and B Sites

Electrochemical energy conversion technologies based on the oxygen evolution reaction (OER) are at the heart of many efforts to achieve a sustainable future, carbon-free fuel, and a circular economy. The sluggish kinetics of oxygen electrocatalysis, as well as the high overpotential required to attain practical current densities, limit the efficiency of several promising electrochemical technologies, including water and carbon dioxide electrolyzers, metal–oxygen batteries, and fuel cells. The most efficient OER catalysts are precious metals such as iridium- and ruthenium-based materials (i.e., IrO2 and RuO2). This fact represents a challenge against the cost-effective implementation of these electrolysis technologies.1-3 As a result, there is a necessity for the development of cost effective PGM-free OER catalysts, with equivalent or superior activity and durability to the PGM catalysts.This presentation will discuss the development and implementation of high-throughput synthesis methodology for PGM-free OER catalysts exploiting the rich chemistry of nanoporous materials4-7 and Argonne National Laboratory's High-Throughput Research Facility. The developed high-throughput methodology will expedite the assessment of the effect of composition and synthesis parameters on the activity of perovskite oxide alkaline electrolyte OER catalysts.AcknowledgementsThis work was supported by the U.S. Department of Energy, Advanced Research Projects Agency Energy (ARPA-E) under the DIFFERENTIATE program. This work was authored in part by Argonne National Laboratory, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.References Katsounaros, Ioannis, Serhiy Cherevko, Aleksandar R. Zeradjanin, and Karl JJ Mayrhofer. "Oxygen electrochemistry as a cornerstone for sustainable energy conversion." Angewandte Chemie International Edition53, no. 1 (2014): 102-121.Lee, Youngmin, Jin Suntivich, Kevin J. May, Erin E. Perry, and Yang Shao-Horn. "Synthesis and activities of rutile IrO2 and RuO2 nanoparticles for oxygen evolution in acid and alkaline solutions." The journal of physical chemistry letters3, no. 3 (2012): 399-404.Cherevko, S. et al. Oxygen and hydrogen evolution reactions on Ru, RuO2, Ir, and IrO2 thin film electrodes in acidic and alkaline electrolytes: A comparative study on activity and stability. Today 262, 170–180 (2016).Nahar, Lamia, Ahmed A. Farghaly, Richard J. Alan Esteves, and Indika U. Arachchige. "Shape controlled synthesis of Au/Ag/Pd nanoalloys and their oxidation-induced self-assembly into electrocatalytically active aerogel monoliths." Chemistry of Materials29, no. 18 (2017): 7704-7715.Farghaly, Ahmed A., Rezaul K. Khan, and Maryanne M. Collinson. "Biofouling-resistant platinum bimetallic alloys." ACS applied materials & interfaces10, no. 25 (2018): 21103-21112.Khan, Rezaul K., Ahmed A. Farghaly, Tiago A. Silva, Dexian Ye, and Maryanne M. Collinson. "Gold-Nanoparticle-Decorated Titanium Nitride Electrodes Prepared by Glancing-Angle Deposition for Sensing Applications." ACS Applied Nano Materials2, no. 3 (2019): 1562-1569.Farghaly, Ahmed A., Mai Lam, Christopher J. Freeman, Badharinadh Uppalapati, and Maryanne M. Collinson. "Potentiometric measurements in biofouling solutions: comparison of nanoporous gold to planar gold." Journal of The Electrochemical Society 163, no. 4 (2015): H3083.

(Invited) Machine Learning Driven Discovery and Optimization of Perovskite Alkaline Electrolyte Oxygen Evolution Reaction Electrocatalysts

Electrochemical energy conversion technologies based on the oxygen evolution reaction (OER) are at the heart of many efforts to achieve a sustainable future, carbon-free fuel, and a circular economy. The sluggish kinetics of oxygen electrocatalysis, as well as the high overpotential required to attain practical current densities, limit the efficiency of several promising electrochemical technologies, including water and carbon dioxide electrolyzers, metal–oxygen batteries, and fuel cells. The most efficient OER catalysts are precious metals such as iridium- and ruthenium-based materials (i.e., IrO2 and RuO2). This fact represents a challenge against the cost-effective implementation of these electrolysis technologies.1-3 As a result, there is a necessity for the development of cost effective PGM-free OER catalysts, with equivalent or superior activity and durability to the PGM catalysts.This presentation will describe the application of machine learning (ML)-guided materials discovery and high-throughput synthesis to address these concerns, taking advantage of the intriguing properties and rich chemistry of nanoporous materials, the demonstrated capability of machine learning (ML)-guided materials discovery, and the high OER electrocatalytic activity of perovskites especially in alkaline media.4-10 Simulation of over 8,000 perovskites across a variety of cell sizes, space groups, and compositions using density functional theory (DFT) has been performed. Mining of the simulation data indicated that experimentally-known perovskites are characterized by low energy above the thermodynamic convex hull. Efficient search algorithms, deep learning-based models, and DFT calculations have been used to explore the space of perovskite oxides to produce novel compositions with tailored electronic descriptors. Promising compositions designed for high activity and stability are then selected for high throughput automated synthesis using the High-Throughput Research Facility at Argonne National Laboratory. A correlation between the phase purity, annealing temperature and OER activity has been identified.AcknowledgementsThis work was supported by the U.S. Department of Energy, Advanced Research Projects Agency-Energy (ARPA-E) under the DIFFERENTIATE program. This work was authored in part by Argonne National Laboratory, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.References Katsounaros, Ioannis, Serhiy Cherevko, Aleksandar R. Zeradjanin, and Karl JJ Mayrhofer. "Oxygen electrochemistry as a cornerstone for sustainable energy conversion." Angewandte Chemie International Edition53, no. 1 (2014): 102-121.Lee, Youngmin, Jin Suntivich, Kevin J. May, Erin E. Perry, and Yang Shao-Horn. "Synthesis and activities of rutile IrO2 and RuO2 nanoparticles for oxygen evolution in acid and alkaline solutions." The journal of physical chemistry letters3, no. 3 (2012): 399-404.Cherevko, S. et al. Oxygen and hydrogen evolution reactions on Ru, RuO2, Ir, and IrO2 thin film electrodes in acidic and alkaline electrolytes: A comparative study on activity and stability. Today 262, 170–180 (2016).Nahar, Lamia, Ahmed A. Farghaly, Richard J. Alan Esteves, and Indika U. Arachchige. "Shape controlled synthesis of Au/Ag/Pd nanoalloys and their oxidation-induced self-assembly into electrocatalytically active aerogel monoliths." Chemistry of Materials29, no. 18 (2017): 7704-7715.Farghaly, Ahmed A., Rezaul K. Khan, and Maryanne M. Collinson. "Biofouling-resistant platinum bimetallic alloys." ACS applied materials & interfaces10, no. 25 (2018): 21103-21112.Khan, Rezaul K., Ahmed A. Farghaly, Tiago A. Silva, Dexian Ye, and Maryanne M. Collinson. "Gold-Nanoparticle-Decorated Titanium Nitride Electrodes Prepared by Glancing-Angle Deposition for Sensing Applications." ACS Applied Nano Materials2, no. 3 (2019): 1562-1569.Farghaly, Ahmed A., Mai Lam, Christopher J. Freeman, Badharinadh Uppalapati, and Maryanne M. Collinson. "Potentiometric measurements in biofouling solutions: comparison of nanoporous gold to planar gold." Journal of The Electrochemical Society163, no. 4 (2015): H3083.Suntivich, Jin, Kevin J. May, Hubert A. Gasteiger, John B. Goodenough, and Yang Shao-Horn. "A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles." Science334, no. 6061 (2011): 1383-1385.Hwang, Jonathan, Zhenxing Feng, Nenian Charles, Xiao Renshaw Wang, Dongkyu Lee, Kelsey A. Stoerzinger, Sokseiha Muy et al. "Tuning perovskite oxides by strain: electronic structure, properties, and functions in (electro) catalysis and ferroelectricity." Materials Today31 (2019): 100-118.Gómez-Bombarelli, Rafael, Jennifer N. Wei, David Duvenaud, José Miguel Hernández-Lobato, Benjamín Sánchez-Lengeling, Dennis Sheberla, Jorge Aguilera-Iparraguirre, Timothy D. Hirzel, Ryan P. Adams, and Alán Aspuru-Guzik. "Automatic chemical design using a data-driven continuous representation of molecules." ACS central science 4, no. 2 (2018): 268-276.

Metal Organic Framework-Based Alkaline Oxygen Evolution Reaction Electrocatalysts: Morphology, Metal Loading, and Durability

Electrochemical energy conversion technologies based on the oxygen evolution reaction (OER) are at the heart of many efforts to achieve a sustainable future, carbon-free fuel, and a circular economy. The sluggish kinetics of oxygen electrocatalysis, as well as the high overpotential required to attain practical current densities, limit the efficiency of several promising electrochemical technologies, including water and carbon dioxide electrolyzers, metal–oxygen batteries, and fuel cells. The most efficient OER catalysts are precious metals such as iridium- and ruthenium-based materials (i.e., IrO2 and RuO2). This fact represents a challenge against the cost-effective implementation of these electrolysis technologies.1-3 The rich chemistry of nanoporous materials provides an opportunity for the development of cost effective PGM-free OER catalysts, with equivalent or superior activity and durability to the PGM catalysts.4-7 Metal organic framework (MOF)-based OER catalysts with high activity and long-term stability in alkaline electrolytes will be discussed in this presentation. We will discuss the relationship between MOF morphology and metal-ion loading, and how their impact on OER activity.Acknowledgements: Argonne National Laboratory is managed for the U.S Department of Energy (DOE) by the University of Chicago Argonne, LLC, under contract DE-AC-02-06CH11357. This work was performed under the auspices of the Electrocatalysis Consortium (ElectroCat 2.0), a DOE Office of Energy Efficiency, Hydrogen and Fuel Cell Technologies (HFTO) consortium. Electron microscopy was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.References Katsounaros, Ioannis, Serhiy Cherevko, Aleksandar R. Zeradjanin, and Karl JJ Mayrhofer. "Oxygen electrochemistry as a cornerstone for sustainable energy conversion." Angewandte Chemie International Edition53, no. 1 (2014): 102-121.Lee, Youngmin, Jin Suntivich, Kevin J. May, Erin E. Perry, and Yang Shao-Horn. "Synthesis and activities of rutile IrO2 and RuO2 nanoparticles for oxygen evolution in acid and alkaline solutions." The journal of physical chemistry letters3, no. 3 (2012): 399-404.Cherevko, S. et al. Oxygen and hydrogen evolution reactions on Ru, RuO2, Ir, and IrO2 thin film electrodes in acidic and alkaline electrolytes: A comparative study on activity and stability. Today 262, 170–180 (2016).Nahar, Lamia, Ahmed A. Farghaly, Richard J. Alan Esteves, and Indika U. Arachchige. "Shape controlled synthesis of Au/Ag/Pd nanoalloys and their oxidation-induced self-assembly into electrocatalytically active aerogel monoliths." Chemistry of Materials29, no. 18 (2017): 7704-7715.Farghaly, Ahmed A., Rezaul K. Khan, and Maryanne M. Collinson. "Biofouling-resistant platinum bimetallic alloys." ACS applied materials & interfaces10, no. 25 (2018): 21103-21112.Khan, Rezaul K., Ahmed A. Farghaly, Tiago A. Silva, Dexian Ye, and Maryanne M. Collinson. "Gold-Nanoparticle-Decorated Titanium Nitride Electrodes Prepared by Glancing-Angle Deposition for Sensing Applications." ACS Applied Nano Materials2, no. 3 (2019): 1562-1569.Farghaly, Ahmed A., Mai Lam, Christopher J. Freeman, Badharinadh Uppalapati, and Maryanne M. Collinson. "Potentiometric measurements in biofouling solutions: comparison of nanoporous gold to planar gold." Journal of The Electrochemical Society 163, no. 4 (2015): H3083.

Fundamental Aspects of the Electron Transfer Processes in Non-Aqueous Redox Flow Batteries

Redox flow batteries (RFBs) have garnered increasing attention for energy storage applications with non-aqueous RFBs offering several advantages such as larger voltage windows and the prospect of high energy densities. To increase the efficacy of non-aqueous RFBs, much effort has gone into the design of redox moieties that are highly soluble, cheaper, and robust, with desired electrochemical properties. To evaluate the capability of these redox moieties for RFB applications, the kinetics and thermodynamics of electron transfer events need to be understood. These insights could help towards rational design of redox moieties and to predict RFB performance. Techniques such as cyclic voltammetry and rotating disk electrode are commonly used to study the fundamental parameters of electron transfer process and thermodynamic properties of the redox moieties in both the neutral and charged states.In this work, we investigate the effects of supporting electrolytes on the thermodynamics and kinetics of the redox moieties. Vanadium (III) acetylacetonate and iron complexes are the bipolar model redox moieties used as both negative and positive electrolyte in non-aqueous RFB applications.1 While many redox moieties are stable in the neutral state, it is during cycling that degradation of the complexes typically occurs. As shown previously, the supporting electrolyte composition plays a key role in the performance and stability of the redox species in RFBs.2 We found that ion pairing between the charged redox moieties and the supporting electrolyte resulted in lower diffusion coefficients, it also has a negative impact on the kinetics of charge transfer process. We propose that the observed ion pairing can explain the stabilizing effects of supporting electrolytes on redox moieties. The magnitude of this effect can be explained by hard soft acid base theory (HSAB) which can be further used to predict the extent of ionic interactions of the charged species in the RFB electrolytes. Acknowledgements: Los Alamos National Laboratory is operated by Triad, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218NCA000001). Authors would like to thank Dr. Imre Gyuk and financial support from the U.S. Department of Energy’s Office of Electricity for the publication of this work is gratefully acknowledged. Sharma, G.A. Andrade, S. Maurya, I.A. Popov, E.R. Batista, B.L. Davis, R. Mukundan, N.C. Smythe, A.M. Tondreau, P. Yang, J.C. Gordon, Iron-iminopyridine complexes as charge carriers for non-aqueous redox flow battery applications, Energy Storage Mater., 37 (2021), pp. 576-586Wei X, Xu W, Huang J, Zhang L, Walter E, Lawrence C, Vijayakumar M, Henderson WA, Liu T, Cosimbescu L, Li B, Sprenkle V, Wang W. “Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All-Organic Redox Flow Battery” Angew Chem Int Ed Engl. 2015, 54 (30): 8684-7.

Pyrolysed Co-N4 Macrocycles on Carbon Supports for the Efficient Electroreduction of CO2

Converting CO2 into materials such as chemicals or synfuels is an attractive way to mitigate greenhouse gas emissions while producing value-added products1-4. Even though the intrinsic chemical stability of CO2 significantly limits its reactivity, the use of electrocatalysts allows its efficient reduction in a mild environment and at relatively low overpotentials5,6. Cobalt phthalocyanine (CoPC), cobalt tetra-phenyl porphyrin (CoTPP) and Vitamin B12 (VB12) are well-defined Co-N4 macrocycles whose incorporation into heterogeneous catalyst setups have led to materials with outstanding CO2 electroreduction reaction (CO2ERR) properties, most notably in the selective formation of CO at high current densities7-11.These Co-N4 macrocycles have also been used to manufacture catalysts efficient for the oxygen reduction reaction (ORR). Notably, the pyrolysis of the macrocyclic precursor supported by carbon materials allowed the fabrication of heterogeneous ORR catalysts with high loadings of catalytically active components, controlled local environments and enhanced stabilities12,13. While these properties could lead to these materials also being efficient catalysts for CO2ERR, to the best of our knowledge, such pyrolyzed catalysts have not been investigated for the CO2 reduction reaction.In this work, we report materials based on CoPC, CoTPP and VB12, supported by carbon black and pyrolyzed under argon, as efficient catalysts for the CO2ERR. The catalytic precursors were dispersed on carbon powders with ball-milling before being annealed at different temperatures chosen from the positions of the significant steps and plateaus observed by thermogravimetric analysis of the pure precursors. The structures of the resulting materials were analyzed by powder X-ray diffraction and X-ray absorption spectroscopy. The electrochemical behaviour of these materials for the CO2ERR were characterized in CO2-saturated potassium bicarbonate (KHCO3) electrolyte using a custom-made flow cell at a range of potentials, and the products of the reaction were analyzed with gas chromatography, 1H NMR spectroscopy and high-performance liquid chromatography.The high reactivity of the catalysts for the reduction of CO2 into CO was maintained for all materials treated at temperatures as high as 700 °C, even though the structures of their active sites were drastically different from that of the precursor molecules. The pyrolyzed materials also exhibited a change in correlation between the CO current densities and the KHCO3 concentration of the electrolyte, indicating that the reaction mechanism had changed compared to that of the pristine materials.1 Peter, S. C. Reduction of CO2 to Chemicals and Fuels: A Solution to Global Warming and Energy Crisis. ACS Energy Letters 3, 1557-1561, doi:10.1021/acsenergylett.8b00878 (2018).2 Lee, Z. H., Sethupathi, S., Lee, K. T., Bhatia, S. & Mohamed, A. R. An overview on global warming in Southeast Asia: CO2 emission status, efforts done, and barriers. Renewable and Sustainable Energy Reviews 28, 71-81, doi:10.1016/j.rser.2013.07.055 (2013).3 Saeidi, S., Amin, N. A. S. & Rahimpour, M. R. Hydrogenation of CO2 to value-added products - A review and potential future developments. Journal of CO2 Utilization 5, 66-81, doi:10.1016/j.jcou.2013.12.005 (2014).4 Zhao, G., Huang, X., Wang, X. X. & Wang, X. X. Progress in catalyst exploration for heterogeneous CO2 reduction and utilization: A critical review. Journal of Materials Chemistry A 5, 21625-21649, doi:10.1039/c7ta07290b (2017).5 Finn, C., Schnittger, S., Yellowlees, L. J. & Love, J. B. Molecular approaches to the electrochemical reduction of carbon dioxide. Chemical Communications 48, 1392-1399, doi:10.1039/c1cc15393e (2012).6 Torbensen, K., Boudy, B., Joulié, D., von Wolff, N. & Robert, M. Emergence of CO2 electrolyzers including supported molecular catalysts. Current Opinion in Electrochemistry 24, 49-55, doi:10.1016/j.coelec.2020.07.001 (2020).7 Wang, M. et al. CO2 electrochemical catalytic reduction with a highly active cobalt phthalocyanine. Nature Communications 10, doi:10.1038/s41467-019-11542-w (2019).8 Ni, W. et al. Dual single-cobalt atom-based carbon electrocatalysts for efficient CO2-to-syngas conversion with industrial current densities. Applied Catalysis B: Environmental 291, doi:10.1016/j.apcatb.2021.120092 (2021).9 Jia, C. et al. Vitamin B12 on Graphene for Highly Efficient CO2 Electroreduction. ACS Appl Mater Interfaces 12, 41288-41293, doi:10.1021/acsami.0c10125 (2020).10 Hu, B. et al. How does the ligands structure surrounding metal-N4 of Co-based macrocyclic compounds affect electrochemical reduction of CO2 performance? Electrochimica Acta 331, 135283, doi:10.1016/j.electacta.2019.135283 (2020).11 Hu, X. M., Ronne, M. H., Pedersen, S. U., Skrydstrup, T. & Daasbjerg, K. Enhanced Catalytic Activity of Cobalt Porphyrin in CO2 Electroreduction upon Immobilization on Carbon Materials. Angew Chem Int Ed Engl 56, 6468-6472, doi:10.1002/anie.201701104 (2017).12 Wan, G. et al. Tuning the Performance of Single-Atom Electrocatalysts: Support-Induced Structural Reconstruction. Chemistry of Materials 30, 7494-7502, doi:10.1021/acs.chemmater.8b02315 (2018).13 Wan, G. et al. Anion-Regulated Selective Generation of Cobalt Sites in Carbon: Toward Superior Bifunctional Electrocatalysis. Adv Mater 29, doi:10.1002/adma.201703436 (2017).