Chemie Research Articles

Graphisches Inhaltsverzeichnis: Angew. Chem. 5/2023

Angewandte ChemieVolume 135, Issue 5 e202380511 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 5/2023 First published: 19 January 2023 https://doi.org/10.1002/ange.202380511AboutPDF 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 Volume135, Issue5January 26, 2023e202380511 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 Note for articles published since 1962: Do not cite this version alone.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

Graphical Abstract: Angew. Chem. Int. Ed. 4/2023

Angewandte Chemie International EditionVolume 62, Issue 4 e202380411 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 4/2023 First published: 16 January 2023 https://doi.org/10.1002/anie.202380411AboutPDF 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 Volume62, Issue4January 23, 2023e202380411 RelatedInformation

Shining a Spotlight on Photochemistry

Shining a Spotlight on Photochemistry

ChemSystemsChem – On the Up and Up

<i>ChemSystemsChem</i> – On the Up and Up

A Bibliometric Analysis of Carbon Dots in Sensors Application

The exponential increase in carbonaceous-based research has prompted the scientific community to apply it to numerous value-added applications. This paper aimed to systematically analyze the comprehensive contributions clusters of publications per year, country, institution, authors, and keywords-wise by using a quantitative review technique called bibliometric analysis. The data was retrieved from the Scopus database to identify the overall scientific trend results with the keyword "carbon dots as a sensor" from 2010 to 2020. The VOSviewer, WordItOut, and Datawrapper are selected as tools for bibliometric analysis and data visualization. In this work, the total citations from the Scopus Core Set and the total citations in the most recent year have only been used for the assessment of highly cited papers. The results showed that after 2014, the number of publications increased significantly with the work related to “carbon dots as sensors.” Thus, comprehensive journals like the Angewandte Chemie - International Edition were the most popular in publishing articles, contributing to almost 6.39% of the research area. The country-wise analysis revealed that China accounted for more than 67.18% of the articles published, followed by the United States and India, comprising 6.24% and 6.13%, respectively. Lastly, keyword cluster analysis revealed five major research hotspots for future discussion. Thus, this analysis provides an important starting point for further studies on research concerning the direction of "carbon dots as a sensor" for positive development in the research area.

Angewandte Chemie: A Team Effort

<i>Angewandte Chemie</i>: A Team Effort

Open for All at ChemElectroChem

Open for All at <i>ChemElectroChem</i>

Graphisches Inhaltsverzeichnis: Angew. Chem. 50/2022

Angewandte ChemieVolume 134, Issue 50 e202285011 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 50/2022 First published: 05 December 2022 https://doi.org/10.1002/ange.202285011AboutPDF 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, Issue50December 12, 2022e202285011 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

Tub-010, a Novel Antibody-Drug-Conjugate with Reduced Nonspecific Toxicity Profile Based on Tub-Tag Technology Widens the Therapeutic Window for the Treatment of CD30+ Malignancies

Introduction: Patients with R/R CD30+ malignancies such as PTCL, CTCL and cHL often lack effective and tolerable therapy options. Available treatments frequently provide only short-term disease control at the cost of significant or cumulative toxicities. Brentuximab-Vedotin (BV, Adcetris®), an MMAE-delivering anti-CD30-ADC, has a high response rate but dose-limiting AEs often result in premature dose reduction or even therapy discontinuation. The maleimide chemistry results in a heterogeneous product (DAR 0-8) with varying PK and potency properties and spontaneous deconjugation can cause premature transfer of linker payload to serum proteins and thereby reduce the tumor selectivity. In consequence, some of the BV-induced toxicity is likely design-based leading to CD30-independent cellular uptake and aggregation of the ADC. Objectives: We aimed to generate a novel CD30-ADC with improved biophysical properties to widen the therapeutic window using Tub-tag-conjugation technology. Material & methods: TUB-010 is a next-generation ADC, implementing a novel conjugation strategy, called Tub-tag® conjugation (Schumacher, Angewandte Chemie 2015). The recombinant Tub-tag sequence, a 14 amino acid peptide derived from α-tubulin and fused to the C-termini of the CD30 mAb light chains, has unique features in that it provides a significant degree of hydrophilicity to counterbalance the payload-derived hydrophobicity, thus enabling superior biophysical properties and product homogeneity. This new technology was used to generate a DAR2-ADC with stably linked MMAE via a Cathepsin B cleavable linker (vc-PAB) and chemoenzymatic conjugation of linker payload using Tubulin-tyrosine ligase (TTL). The resulting ADC was tested for physicochemical properties, homogeneity, stability, internalization, preclinical efficacy, nonspecific uptake and general cytotoxicity in primary cells, cell lines, rats & cynomolgus monkeys. Results: Tub-tag technology enabled us to create a DAR2 anti-CD30-ADC with a binding affinity, internalization and lysosomal release characteristics similar to BV. In contrast to BV, TUB-010 is a homogeneous DAR2 ADC. The linker-payload is chemically stably attached to the mAb with neglectable premature deconjugation while in circulation, whereas protease-mediated release of MMAE within the lysosome occurs normally as expected with the vc-PAB linker. The increased ADC stability prior to internalization via CD30 leads to reduced nonspecific transfer of linker-payload to serum proteins, and overall improved PK parameters in rats. The hydrophobicity of MMAE is counterbalanced by hydrophilicity provided by the Tub-tag peptides, which resulted in > 5-fold reduced ADC aggregation under stress conditions compared to BV. The increased hydrophilicity of the overall ADC reduced nonspecific cellular uptake and consecutive cellular toxicity vs BV within the clinically therapeutic range by factor 2- to >10-fold in various human primary cells (Fig. A). When normalized to the MMAE concentration, TUB-010 showed similar in vitro cytotoxic efficacy as well as similar bystander activity compared to BV on established cancer cell lines from cHL, PTCL and CTCL patients with various levels of CD30 expression (Fig. A). In vivo, TUB-010 exerted significantly improved tumor control compared to BV when both ADCs were dosed at equal MMAE concentration in the Karpas-299 cell-derived ALCL xenograft model (Fig. B). In cynomolgus monkey dose range finding and GLP toxicity studies, TUB-010 administered 2 or 4 times Q3W in a dose range of 6-15 mg/kg showed a 5-fold widened therapeutic window for the ADC as the MTD was not reached. Hematological toxicity was reduced compared to BV and no signs of anatomical of functional tissue damage were detectable. Conclusions: Tub-tag technology allows the reduction of nonspecific target-independent toxicity of ADCs in preclinical models by improving key design issues in current ADCs such as stability and overall biophysical features. TUB-010 is a promising, novel and potential best-in-class CD30-ADC which can deliver the cytotoxic payload to CD30+ malignancies with higher precision and with a wider therapeutic window than BV. These features suggest that TUB-010 may increase the clinical benefit with CD30-targeting ADC therapy for patients with CD30+ malignancies. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The fullerene awakens

Recently in <i>Angewandte Chemie</i>, Kim and co-workers employed a large Zn-porphyrin paneled cage to activate C₆₀ toward inverse electron-demand Diels-Alder reaction with a tetrazine through precise pre-organization of the reaction partners. Subsequent hydration-induced rearrangement resulted in displacement of the reaction product, enabling catalytic turnover.

Graphisches Inhaltsverzeichnis: Angew. Chem. 45/2022

Angewandte ChemieVolume 134, Issue 45 e202284511 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 45/2022 First published: 31 October 2022 https://doi.org/10.1002/ange.202284511AboutPDF 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 Volume134, Issue45November 7, 2022e202284511 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

Graphisches Inhaltsverzeichnis: Angew. Chem. 43/2022

Angewandte ChemieVolume 134, Issue 43 e202284311 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 43/2022 First published: 18 October 2022 https://doi.org/10.1002/ange.202284311AboutRelatedInformationPDFPDF ToolsRequest permissionAdd to favorites ShareShare Give accessShare full text accessClose modalShare 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 Volume134, Issue43October 24, 2022e202284311 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

Graphical Abstract: Angew. Chem. Int. Ed. 43/2022

Angewandte Chemie International EditionVolume 61, Issue 43 e202284311 Graphical AbstractFree Access Graphical Abstract: Angew. Chem. Int. Ed. 43/2022 First published: 18 October 2022 https://doi.org/10.1002/anie.202284311AboutPDF 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 Volume61, Issue43October 24, 2022e202284311 RelatedInformation

Graphisches Inhaltsverzeichnis: Angew. Chem. 42/2022

Angewandte ChemieVolume 134, Issue 42 e202284211 Graphisches InhaltsverzeichnisFree Access Graphisches Inhaltsverzeichnis: Angew. Chem. 42/2022 First published: 10 October 2022 https://doi.org/10.1002/ange.202284211AboutPDF 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, Issue42October 17, 2022e202284211 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

(Invited, Digital Presentation) Methane Conversion to High Value Chemicals By Photocatalysis

As underlined in the COP26, methane as a greenhouse gas is nearly 80 time more potent than CO2 while its reserve is much more than the sum of coal, oil and natural gas. Thus methane conversion not only involves the environmental issue but also is related to high-value chemical production /clean energy supply, which has been attracting substantial interest over the last decades. However CH4 activation is energy intensive and kinetically very challenging so that methane activation is regarded as the “holy grail” in the catalytically chemical process. [1] Photocatalysis provides a cost efficient potential to activation of such small molecule under very mild conditions, while to achieve the potential is a huge challenge.[2]Stimulated by our research outcomes on the charge dynamics in inorganic semiconductor photocatalysis, which reveal that the low reaction efficiency is due to both fast charge recombination and large bandgap of an inorganic semiconductor [3,4], together with the recent findings on atomic catalysis [5], we developed novel material strategies for photocatalytic methane conversion to methanol. Highly dispersed atomic level iron species immobilised on a TiO2 photocatalyst show an excellent activity for methane conversion, resulting into ~97% selectivity towards alcohols operated under ambient conditions by a one-step chemical process [6]. Such photocatalyst is also very stable, promising an attractive industrial process of methane upgrade. The dominating function of the iron species has also been investigated in detail. Furthermore, we designed a flow system for relatively efficient methane to C2, achieving the benchmark results in this area.[7] In addition, C1 oxygenates can be produced with nearly 100% by photocatalytic methane conversion due to the synergy between Au and Cu cocatalysts loaded on ZnO.[8] References ： Li, X. Wang, C., Tang, J. Nature Reviews Materials , 2022, Doi: 1038/s41578-022-00422-3.Wang Y., Suzuki H., Xie, J., Tomita, O., Martin, D. J., Higashi, M., Kong, D., Abe R. Tang, J., Chem. Rev., 2018, 118: 5201-5241.Tang, J. Durrant J. R., Klug, R ., J. Am. Chem. Soc ., 2008, 130(42) : 13885-13891.Miao, T., Wang, C., Xiong, L., Li, X., Xie, X., Tang, J., ACS Catalysis , 2021, 11, 8226-8238.Wang, A. Li J., Zhang. T., Nat . Rev. Chem ., 2018, 2; 65-81.Xie, J., Jin, R. ,Li, A., Bi, Y., Sankar, G. , Ma , Tang, J. Nature Catalysis , 2018, 1: 889-896.Li, X., Xie J.,Rao, H., Wang, , Tang, J., Angewandte Chemie International Edition , 2020, 132: 19870-19875.Luo, L., Gong, Z., Xu, Y., Ma, J., Liu, H., Xing, J., Tang, J., Journal of the American Chemical Society , 2022, 144, 2, 740–750.

The Effect of Surface-Abundant Hydrogen Bonding on the Electrolyte Reduction for the Stable SEI in Lithium Metal Batteries

Lithium (Li) metal anodes (LMAs) have been attracted world-wide attention as an ideal anode because of its extra-high theoretical capacity (3860 mAh g-1) and low electrode potential (-3.04 V vs S.H.E.). However, the dendritic growth of Li and low Coulombic efficiency (CE) are still hindering their practical uses [1]. To date, numerous methods such as construction of artificial solid electrolyte layer (ASEI) [2], adoption of 3D current collector [3], and tuning of the electrolyte composition [4] have been proposed to prevent Li dendrite growth and increase the CE. Among them, introducing functional additives is one of the most efficient approaches for practical application considering its cost-effectiveness. Until now, various functional additives were introduced to form stable and robust SEI layer in LMBs [4]. Among them, lithium nitrate (LiNO3) is considered as the most efficient electrolyte additive, ensuring high coulombic efficiency (CE) as well as long lifespan of LMBs. When LiNO3 is dissolved in the electrolyte, NO3 - anions are mainly reduced to form inorganic species such as Li3N, which has a high ionic conductivity and mechanical strength. As such species contribute to the construction of the robust and ionic-conductive SEI layer, and hence the reduction of NO3 - is important for stable Li cycling. In this regard, many researchers have focused on increasing reduction of NO3 - by using high-concentration LiNO3 [4], or adding solubilizer to increase more NO3 - in the electrolyte [5]. However, those remedies are still insufficient because most of them increase the viscosity of electrolyte leading to low kinetics, hence a novel and more efficient way to increase NO3 - reduction is needed for practical application.On the other hand, recent researches have reported that the preferential reduction of specific anions is possible by regulation of inner Helmholtz plane (IHP) structure [6]. For instance, Huang et al. reported that intermolecular force between PF6 - anions and surface adsorbent tris(trimethylsilyl) borate could derive in PF6 --abundant IHP, successfully resulted in LiF-rich SEI layer to increase the stability of LMA [6]. Inspired by those works, we expected that NO3 --derived SEI layer would be achieved by using surface adsorbent showing strong intermolecular interaction with NO3 -.In this context, we introduce the adoption of thiourea (TU) as a catalytic additive for the LiNO3 reduction during the SEI formation. Due to its unique molecular structure, addition of TU could induce NO3 - derived SEI layer. Firstly, TU could adsorb onto metallic surface by its S atom. Meanwhile, thiourea could form hydrogen bonding with NO3 - anion by its N-H bonds [7]. Hence in the presence of TU, we suggest that NO3 --abundant electrode surface would be achieved by interaction between TU-NO3 -, resulting in Li3N-rich SEI layer.The adsorption behavior of TU on the Cu electrode was investigated by potential of zero charge (PZC) measurement (Figure 1(a)). As the TU concentration increases, PZC decreases, indicating more surface coverage by TU. Figure 1(b) shows 1H NMR spectra of electrolytes with different components. Upshift displacement of N-H bond of TU were detected after addition of DME and LiTFSI, indicating that intramolecular H-bond of TU were weakened. By contrast, downshift displacement appeared when LiNO3 was added, which means NO3 - would form strong hydrogen bonding with TU. Furthermore, linear scanning voltammetry (LSV) curves at different concentration of TU were measured to investigate the effect of TU on electrolyte reduction (Figure 1(c)). The distinct peaks at 1.6 V and 1.3 V in the cell with 5 wt% LiNO3 indicate reduction of LiNO3 and LiTFSI, respectively. Interestingly, in the presence of TU, negative potential shift and increased current of those redox peaks were shown, indicating that the TU significantly increases the LiNO3 reduction.Importantly, from the XPS analysis, it was found that more abundant Li3N components are in the ASEI layer with TU than that without TU, implying that TU accelerates the reduction of LiNO3 (Figure 2(a-b)). As a result, Li|Cu@ASEI with TU shows better cyclability and higher average CE of 96.44% during 80 cycles compared to Li|Cu@NSEI and Li|Cu@ASEI w/o TU (Figure 3). In addition, morphological and chemical investigation on the favorable ASEI layers assisted by TU, and its electrochemical performance in LMBs will be discussed in this presentation.[1] Cheng et al, Chem. Rev, 117, 10403, 2017.[2] Lopez Jeffrey, et al. JACS 140.37 (2018): 11735-11744.[3] Yang Chun-Peng et al. Nature communications 6.1 (2015): 1-9.[4] Kang et al. Journal of Power Sources 490 (2021): 229504.[5] Zhang et al. Advanced Materials 32.24 (2020): 2001740.[6] Huang et al. Angewandte Chemie. 60.35 (2021): 19232-19240.[7] Nishizawa et al. Tetrahedron letters 36.36 (1995): 6483-6486. Figure 1

Insights into the Crystal Structure of Halide Solid Electrolytes and Li Diffusion

Lithium halides with general formula Li3MX6 (M = metals such as Y, In, Yb or Sc; X = Cl or Br) have attracted significant attention because of their promising room temperature conductivities and high oxidative stability[1]. Li-ion mobility in these halides is strongly affected by the synthesis method and parameters. In Li3YCl6 with a hexagonal-close-packed (hcp) anion framework, the ionic conductivity is commonly observed to decrease with increased crystallinity. While in Li3YBr6 with a face-centered-cubic (fcc) anion framework, the ionic conductivity increases with increased crystallinity. So far there is no clear explanation for such opposite trends in these two otherwise very similar crystal structures. Ab initio molecular dynamics (AIMD) simulation[2] suggested higher ionic conductivity and lower activation energy in Li3YCl6 than inLi3YBr6, which also does not agree well with the experimental observation that Li3YBr6 commonly shows higher conductivity than Li3YCl6. Above-mentioned unexplained observations and inconsistencies imply that likely some critical structural features of these halides that strongly impact ionic diffusion are not yet explored nor taken into consideration. Here, we report our recent findings in the crystal structure of Li3YCl6 and Li3YBr6 and the design, synthesis and electrochemical testing of a few new halide compounds designed based on the new findings. The crystal structures are investigated with using ex situ and in situ synchrotron X-ray diffraction (XRD) and neutron diffraction (ND). Our study[3] demonstrated that the discrepancies between simulated and experimental results in Li3YBr6-type structure is partly caused by the grain boundary. Through PDF data analysis, we provide experimental evidences of cation local ordering in ab plane and stacking fault along c-direction in Li3YBr6-type structure. The lower ionic conductivity in low crystallinity is owing to the blockage of Li diffusion channel along c-direction caused by the stacking fault. Moreover, a new tetrahedral Li-site is identified, which may be critical in understanding the Li diffusion behaviors. Via rationally tuning Li occupancies at the tetrahedral and octahedral sites, low Li diffusion barriers can be achieved, which is in consistence with theoretical calculation results.[1] T. Asano, A. Sakai, S. Ouchi, M. Sakaida, A. Miyazaki, S. Hasegawa, Advanced Materials 2018, 30, 1803075.[2] S. Wang, Q. Bai, A. M. Nolan, Y. Liu, S. Gong, Q. Sun, Y. Mo, Angewandte Chemie International Edition 2019, 58, 8039-8043.[3] Z. Liu, S. Ma, J. Liu, S. Xiong, Y. Ma, H. Chen, ACS Energy Letters 2021, 6, 298-304.

Oxygen Reduction Reaction on Fe-N-C Catalysts: A Computational Spectroscopy Study

The oxygen reduction reaction (ORR) plays an important role in proton exchange fuel cells (PEFCs). In PEFCs, ORR is the cathodic half-cell reaction complementary to the oxidation of the fuel, but since ORR has slow kinetics, it requires high amounts of catalyst. State-of-the-art ORR catalysts are based on the expensive metal platinum. Even though the amount of platinum needed for ORR in PEFCs has been reduced significantly over the last decade, it is still the major contributor to the cost of PEFCs, thus hindering the commercialization and accessibility of this technology.[1]Iron and nitrogen doped carbon (Fe-N-C) catalysts have gained a lot of research attention due to their high ORR activity, which makes them potential substitutes for platinum-based catalysts. In Fe-N-C catalysts, iron is thought to be atomically dispersed as pseudo-molecular active centres with four- or fivefold nitrogen coordination spheres which are embedded in graphene layers. Since Fe-N-C catalysts are typically prepared via pyrolysis, they have a highly amorphous structure and can contain multiple iron phases, which makes them difficult to characterize structurally and spectroscopically. Consequently, there is still a scientific debate on the exact nature of the active site, in terms of iron spin and oxidation states and its precise coordination environment.[2-4]Fe-57 Mössbauer spectroscopy can provide direct insights on iron spin and oxidation states and is used successfully to characterise the amorphous Fe-N-C catalysts. Until recently, the interpretation of Mössbauer spectra was limited to comparisons with small reference complexes which lack the extended π-systems of Fe-N-C catalysts.[2] Since synthesis of such extended π-systems as references is difficult, we have developed a library of computational models that encompasses different structural motifs and electronic structures. With increasing use of in situ and operando experiments on Fe-N-C catalysts, the interest in computational models for the interpretation of experimental Mössbauer spectra has grown.[4-6] In this contribution, we present our density functional theory results for different molecular Fe-N-C models with extended π-systems and discuss their electronic structures and spectroscopic properties.[1] L. Osmieri, et al. Current Opinion in Electrochemistry 2021, 25, 100627.[2] U. I. Kramm, et al. Advanced Materials 2019, 31, 1805623.[3] S. Wagner, et al. Angewandte Chemie International Edition 2019, 58, 10486.[4] L. Ni, C. Gallenkamp, et al. Advanced Energy & Sustainability Research 2021, 2, 2000064.[5] J. Li, et al. Nature Catalysis, 2021, 4, 10.[6] X. Liu, et al. Chem 2020, 6, 3440.

Plasma Electrochemistry: Redox Reactions in Gases

Electrochemistry underpins numerous commercially important processes ranging from energy generation to sensors and coating deposition. A common and –so far– essential feature of all these processes involve a redox active species dissolved in a solvent which serves to allow charge exchange between electrodes. Rather than being inert, the solvent is without exception redox-active at extreme potentials and thus restrict the breadth of observable reactions to a narrow potential window of approx. -2.5 to +2.5 V vs. NHE. Gaseous electrolytes have typically been ignored due to their feeble electrical conductivity. However, recently with the advent of new accessible approaches to form stable plasmas, these electrically conducting gases are attracting some significant interest and are now being investigated as exotic electrochemical environments. The scope of this work is to apply the well-healed cornerstones of electrochemistry developed almost exclusively in liquids, to the new context of gaseous plasma.The defining property of plasmas is presence of free electrons; because of this they may be considered as both electrodes or electrolytes1&2. We describe results supporting both modes. As electrodes, we show that metal oxides on surfaces may be reduced to zero valent metals using a helium atmospheric plasma jet.3&4 We show that free electrons do indeed reduce a copper oxide film, which may be carefully controlled by surface bias.5 A gaseous flame doped with electroactive species may be considered as electrolytes. Using a three-electrode system6, we may measure unique voltammograms for a series of small organic molecules and amino acids.7 Except for leucine and isoleucine, all were distinguishable. The reduction signatures originate from specific electron attachment reactions of radicals formed via incomplete combustion and fragmentation of the parent molecules. In this case without a solvent we have an extended potential window and our voltammograms extend between 0 and -10 V, which gives unprecedented access to chemistry not previously accessible in liquids. Moreover, mass transport properties are far better than in liquids, as such the fluxes of electroactive species to the electrode a much greater. References Rumbach, P.; Bartels, D. M.; Sankaran, R. M.; Go, D. B., The solvation of electrons by an atmospheric-pressure plasma. Nature Communications 2016, 6, 7248.Elahi, A.; Fowowe, T.; Caruana, D. J., Dynamic Electrochemistry in Flame Plasma Electrolyte. Angewandte Chemie-International Edition 2012, 51 (26), 6350-6355.Sener, M. E., Quesada Cabrera, R., Parkin, I.P., Caruana, D. J., Facile formation of black titania films using an atmospheric-pressure plasma jet, Green Chemistry 2022, 24, 2499-2505.Sener, M. E., Palgrave, R., Quesada Cabrera, R., Caruana, D. J., Patterning of Metal Oxide thin Films using H2/He Atmospheric Pressure Plasma Jet. Green Chemistry 2020, 22, 1406-1413.Sener, M. E.; Caruana, D. J., Modulation of copper(I) oxide reduction/oxidation in atmospheric pressure plasma jet. Electrochemistry Communications 2018, 95, 38-42.Fowowe, T.; Hadzifejzovic, E.; Hu, J. P.; Foord, J. S.; Caruana, D. J., Plasma Electrochemistry: Development of a Reference Electrode Material for High Temperature Plasma. Advanced Materials 2012, 24 (47), 6305-6309.Calleja, M.; Elahi, A.; Caruana, D. J., Gas phase electrochemical analysis of amino acids and their fragments. Communications Chemistry 2018, 1, 48.

Machine Learning and High Throughput Synthesis Acceleration of the Discovery of Alkaline Electrolyte Oxygen Evolution Reaction Electrocatalysts

Accelerating the development and discovery of new catalysts is vital for advancing many electrochemical energy conversion technologies (EECT) required to achieve a sustainable future utilizing carbon-free fuel, a circular economy, and to meet the grand energy challenges of the 21st century. The oxygen evolution reaction (OER) is at the heart of many EECT such as water and carbon dioxide electrolyzers, fuel cells, and metal-oxygen batteries. The sluggish kinetics of oxygen electrocatalysis, resulting high overpotential necessary to attain practical current densities, and the high cost of the state-of-the-art OER platinum group metal (PGM) and precious metals catalysts (i.e., IrO2 and RuO2) limit the cost-effective implementation and development of several promising electrolysis technologies.1-3 The development of alternative PGM-free OER catalysts, with comparable or superior activity and durability to the PGM catalysts and derived from earth-abundant materials has thus been an active research area for decades.The application of perovskite oxides as PGM-free electrocatalysts for the OER in alkaline environments has seen significant research interest in the last decade, with tri-metallic and tetra-metallic compounds showing activities comparable to PGM-based catalysts.4,5 The chemical space of these compounds is exceptionally large, yet the development of new perovskite oxides with high OER performance (activity and durability) has been limited and often discovered through trial and error, a time and cost inefficient route that restricted the discovery of more advanced materials. Recent advances in high-performance computing, machine learning (ML), and high throughput material synthesis and screening technologies have enabled high-throughput catalyst design and discovery.4-10 This presentation will describe how the machine learning and high throughput synthesis technologies worked synergistically to accelerate the discovery of alkaline oxygen evolution reaction electrocatalysts. The role of ML in accelerating the materials synthesis and the role of high throughput synthesis in optimizing the ML model predictions will be discussed.AcknowledgmentsThis 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 science4, no. 2 (2018): 268-276.