bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proton-Conducting Ceramics for Electrochemical Ammonia Synthesis
Authors: Herradon Carolina , Le Long , Meisel Charlie , Cadigan Chris , O'Hayre Ryan , Sullivan Neal P. 
Published: July 2021

We report our progress in developing proton-conducting ceramics for flexible storage of intermittent renewable electricity in the form of ammonia. Various electrochemical and thermochemical synthesis strategies have been investigated in pursuit of “green ammonia”. Electrochemical ammonia synthesis can harness water-splitting to source hydrogen, displacing steam-methane reforming widely used in conventional ammonia production through the well-established Haber-Bosch process (HB).
This electrochemical approach potentially provides an efficient solution to the energy-storage challenges presented by the expanding market penetration of solar and wind power. The intermittent nature of these renewables presents strain on the conventional power plants tasked with stable electricity production. Through creative application of novel proton-conducting electroceramics, intermittent renewable electricity can be used to drive the synthesis of green ammonia, effectively storing electricity in the form of an easily transported, carbon-neutral, energy-dense commodity chemical. Further, the process is reversible; NH3 can be electrochemically re-converted back into electricity as needed in meeting peak load demands.
Displacing Haber-Bosch proves challenging, as it requires process solutions that can simultaneously achieve high NH3 conversion and high NH3-synthesis rate while minimizing energy costs. The Haber-Bosch process achieves both through high-pressure operation (up to 300 bar), where thermodynamics are more favorable. Electrochemical systems have yet to reach this stage of technological development. All previous work has been limited to atmospheric-pressure operation, where NH3-synthesis rates are orders-of-magnitude lower. Further, most reports on electrochemical ammonia synthesis have utilized molecular H2 as the source of protons for NH3 synthesis, rather than water electrolysis as described here.
In this work, we present our efforts to apply proton-conducting ceramics to enable electrochemical ammonia synthesis from H2O and N2 feedstocks. Protonic ceramics are emerging materials finding applications in efficient electricity generation, energy storage, and fuels synthesis. As shown in the figure, renewable electricity is used to drive hydrogen production through high-temperature water splitting in the protonic-ceramic electrolyzer. The hydrogen mixes with nitrogen and is then converted to NH3 over a ruthenium catalyst. The process is executed at pressures up to 12 bar, bringing significant challenges in packaging of the protonic ceramic and the catalyst. In this presentation, we review our progress in establishing pressurized operation, and the benefits it brings to electrochemical synthesis of ammonia.

Figure 1
Electrolyte-Coordination-Induced Electrochemical Multiple Electron Oxidation of 2,5-Diarylthiophenes
Authors: Shida Naoki , Maekawa Takuma , Tomita Ikuyoshi , Inagi Shinsuke 
Published: July 2021

Chalcogenophene is a five membered aromatic ring containing group 16 elements, and widely used for the design of small molecule or polymer based organic devices. Previously, we have reported a thorough discussions on the electrochemical redox chemistry of tellurium-containing chalcogenophenes, tellurophene (N. Shida, H. Nishiyama, F. Zheng, S. Ye, D. S. Seferos, I. Tomita, S. Inagi, Communications Chemistry, 2019, 2, 124.). We found that the electrochemical oxidation of 2,5-diaryltellurophene in non-coordinating electrolyte resulted in one-electron oxidation product, while two-electron oxidation preferably proceeded in coordinating electrolyte. These results suggest that the design of electrolyte crucially affect the redox chemistry of chalcogenophenes.
In this study, we report that the electrochemical redox behavior of 2,5-diarylthiophene also varies significantly depending on the coordination of the electrolyte. Specifically, we have found that the coordination of the electrolyte alters the number of electrons in the oxidation of 2,5-diarylthiophene. It was also found that the species generated by the multiple electron transfer in coordinating electrolyte showed a unique reactivity, and proceeded to an unprecedented dimerization reaction to give sulfonium salts.
Distance Dependence of Electron Transfer through Conformationally Constrained Peptides
Authors: Antonello Sabrina , Maran Flavio 
Published: July 2021

Understanding and the ability of peptides to mediate long-range electron tunneling in proteins is an evergreen topic. In this context, the study of electron transfer (ET) through model peptides has been particularly useful, especially to assess the occurrence (or competition) of the superexchange and sequential hopping mechanisms as a function of the structure and length of the peptide bridge. In previous studies [1,2], we stressed the importance of dealing with peptides with a well-defined and rigid structure to properly correlate kinetic and structural data. This structural control was made possible by using model peptide bridges based on oligomers of the α-aminoisobutyric acid (Aib) residue. The Aib unit is characterized by a marked steric hindrance at the α-carbon, and this allows the preparation of very rigid peptides. Rigidity is ensured by a framework of intramolecular C=O···H-N hydrogen bonds. Consequently, these peptides possess a strong dipole moment along the main axis [3]. In previous studies, we used cyclic voltammetry to study the dissociative ETs in two series of Donor − Aib-peptide − Acceptor systems in which we changed the donor group, whereas the acceptor was kept constant (a dialkyl peroxide moiety, resulting in the cleavage of the O-O peroxide bond [4]). In this communication, we describe the outcome of dissociative ETs carried out using a new series of Donor − Aib-peptide − Acceptor system in which the acceptor was a perbenzoate moiety [5]. This change also affects the dissociative ET driving force. The same peptide-length dependent dissociative ETs were tested for a possible solvent effect.
References
[1] Antonello, S.; Formaggio, F.; Moretto, A.; Toniolo, C.; Maran, F. J. Am. Chem. Soc.
2003, 125, 2874.
[2] Polo, F.; Antonello, S.; Formaggio, F.; Toniolo, C.; Maran, F. J. Am. Chem. Soc.
2005, 127, 492.
[3] Gobbo, P.; Antonello, S.; Guryanov, I.; Polo, F.; Soldà, A.; Zen, F.; Maran, F. ChemElectroChem
2016, 3, 2063.
[4] Antonello, S.; Venzo, A.; Maran, F. J. Electroanal. Chem.
2011, 660, 234.
[5] Zuliani, C.; Formaggio, F.; Scipionato, L.; Toniolo, C.; Antonello, S.; Maran, F. ChemElectroChem
2020, 7, 1225.
Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and Its Application to Drug Uptake Studies in Ovarian Cancer Cells
Authors: Luu Huy Tran Le , Nachtigal Mark W. , Kuss Sabine 
Published: July 2021

Epithelial ovarian cancer affects approximately 240,000 women worldwide with an estimated of 152,000 deaths per year. Common treatments include surgery or chemotherapy using a combination of carboplatin and taxane. Unfortunately, approximately 75% patients relapse within 18 months. Of these relapsed patient, an estimate of 85% experience carboplatin resistance. The effect is devastating. One way to combat this emerging drug resistance problem is the development of novel drugs. However, cellular mechanisms of carboplatin-resistance are poorly understood. Without a thorough understanding of resistance mechanisms, developing long-lasting effective drugs for long term treatment is a challenging problem. Therefore, there is a dire need to develop methods to detect and study resistance mechanisms.
One suggested mechanism is the inhibition of drug uptake to prevent the intracellular accumulation of the drug. The presented work describes the quantification of carboplatin uptake in ovarian cancer cells. For this purpose, carboplatin is thoroughly characterized by voltammetry and its suitability for physiological bioelectrochemical studies is assessed. Diffusion and adsorption processes of carboplatin are evaluated, its dependence on pH is investigated, and a limit of detection for carboplatin at unmodified Pt electrodes is identified, without the need of expensive and time-intense electrode modification strategies. The influx and efflux of carboplatin into/from ovarian cancer cells are quantified by electrochemistry to better understand mechanisms of carboplatin chemoresistance. Results emerging from this research will be important for future medical research developing novel agents to combat chemoresistance and will present the basis for future long-term funding applications under this collaboration.
Reference:
Luu H.T.L., Nachtigal M.W., Kuss S.: Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and its Application to Drug Uptake Studies in Ovarian Cancer Cells. Journal of Electroanalytical Chemistry 2020, 872C, 114253.
Monitoring “Real-Time” Biological Binding Events on a Microelectrode Array
Authors: Zhu Yu , Moeller Kevin D 
Published: July 2021

Because microelectrode arrays contain collections of spatially isolated electrodes that can each be individually addressed, they provide an intriguing platform for monitoring the activity of small molecules, peptides, and proteins. The arrays are utilized by placing the members of a molecular library on the surface of the array above the electrodes such that each unique member of the library is located on top of a unique electrode or a set of electrodes in the library. In this way, the binding activity on the molecular library and the electrochemical reactions happen on the electrodes are coupled. The binding events between the molecules on the surface of the array and molecules in solution can thus be monitored with the change of behavior of the electrochemical reactions on the electrodes. The overall strategy is illustrated in Figure below.
We are expanding the types of experiments that can be employed to examine enzyme-peptide binding with the use of microelectrode array. We have previously shown RGD-peptide/ integrin, v-107/ VEGF, and R6A - Gαi1 interactions can be monitored on an array. While success of the synthetic chemistry can be ensured by fluorescence labeling, the binding can be monitored by cyclic voltammogram.
Now, our focus has moved from distinguishing specific binding/non-specific binding/no binding to distinguishing different types of specific binding events. We are working to employ those electrochemical methods in conjunction with the traditional FRET studies in order to provide unique insights into the mechanism of peptide cleavage reactions. In so doing, we hope to add new capabilities to existing surface analytical methods.

Figure 1
Catalysis of Redox-Neutral Reactions By Electron Exchange between Electrodes and Organic Compounds
Authors: Roesel Arend , Broese Timo , Prudlik Adrian , Francke Robert 
Published: July 2021

To most chemists the term ‘electrocatalysis’ is known as the facilitation of a heterogeneous electron transfer via a chemical interaction between the electrode and a substrate [1]. The opposite case, the utilization of a heterogeneous electron exchange to catalyze a chemical reaction (‘electrochemical catalysis’), is a much less known but yet a very powerful approach in electrosynthesis [2]. Here, the injection (or removal) of an electron into (or from) a substrate triggers a redox-neutral reaction (e.g. a molecular rearrangement) that may otherwise require harsh conditions and/or the use of reagents. Such processes involve the electrogeneration of an ionic or radical ionic species, which after a coupled chemical step either undergoes a backward electron exchange with the electrode (ECEb mechanism) or triggers a chain process in the bulk solution. Under these circumstances, sub-stoichiometric amounts of charge are sufficient to achieve a full conversion and conceptionally, the electrons and holes can be understood as being catalysts.
In this contribution, the concept of electrochemical catalysis will be illustrated using the Newman-Kwart rearrangement (NKR) of O-aryl thiocarbamates 2 to the corresponding S-aryl compounds 3 as an example (see scheme below) [3]. Generally, the NKR represents the key-reaction in the three-step synthesis of thiophenols 4 from phenols 1 and proceeds between 200 and 300 °C [3]. Electrochemical catalysis, however, allows for operation at room temperature and provides a complementary reactivity with respect to the arene substitution [3,4]. The results of batch and flow electrolysis will be presented, along with a detailed mechanistic analysis based on cyclic voltammetry studies, control experiments, and quantum chemical calculations.

References:

[1] R. Francke, B. Schille, M. Roemelt, Chem. Rev.
2018, 118, 4631.
[2] R. Francke, R. D. Little, ChemElectroChem.
2019, 6, 4373.
[3] T. Broese, A. F. Roesel, A. Prudlik, R. Francke, Org. Lett.
2018, 20, 7483.
[4] A. F. Roesel, M. Ugandi, N. T. T. Huyen, M. Majek, T. Broese, M. Roemelt, R. Francke, J. Org. Chem.
2020, 85, 8029.

Figure 1
(Organic and Biological Electrochemistry Division Manuel M. Baizer Award) Concepts for Electrifying Organic Synthesis
Authors: Waldvogel Siegfried R 
Published: July 2021

The direct use of electrochemistry for the generation of reactive intermediates can have major advantages towards conventional synthetic strategies.[1] Less or no reagent waste is generated and new reaction pathways are accessible.[2] In order to exploit the electricity driven conversions for synthetic purposes and to install unique selectivity two modern approaches will be outlined:

Solvent-controlled selective dehydrogenative cross-coupling reactions: A key for this is the use of boron-doped diamond anodes and fluorinated alcohols within the electrolyte.[3] This methodology opened new pathways for innovative and scalable arylation reactions.[4]

New electrode systems for the anodic and cathodic conversion to value-added organic compounds. These systems are capable to go beyond common limits in electro-organic synthesis.

The working horse to identify suitable electrolytic conditions is the electrosynthetic screening approach. This strategy gives also rise to fast optimization and subsequent scale-up.[5]

References:
[1] E.J. Horn, B.R. Rosen, P.S. Baran, ACS Cent. Sci.
2 (2016) 302-307.
[2] a) S. Möhle, M. Zirbes, E. Rodrigo, T. Gieshoff, A. Wiebe, S. R. Waldvogel, Angew. Chem. Int. Ed. 57 (2018) 6018-6041; b) A. Wiebe, T. Gieshoff, S. Möhle, E. Rodrigo, M. Zirbes, S. R. Waldvogel, Angew. Chem. Int. Ed. 57 (2018) 5594-5619.
[3] L. Schulz, S.R. Waldvogel, Synlett 30 (2019) 275-286.
[4] S.R. Waldvogel, S. Lips, M. Selt, B. Riehl, C.J. Kampf, Chem.
Rev., 118 (2018) 6706-6765.
[5] C. Gütz, B. Klöckner, S.R. Waldvogel, Org. Process Res. Dev. 20 (2016) 26-32.
Visualization of Mossy Zinc Electroplating Structure Evolution Via Operando Nanotomography
Authors: Wang Fan , Ge Mingyuan , Hitt Andrew , Xiao Xianghui , Guo Hua , Lee Wah-Keat , Savsatli Yavuz 
Published: July 2021

Dendrite growth during electrodeposition is a critical challenge faced by high-energy metallic electrodes (e.g. Li, Zn) in rechargeable batteries. Under typical battery operation conditions, mossy structure forms on Li and Zn anode surface, which may be described as colonies of intertwined and branched filaments with diameters of ~ 100 nm. Compared to the well-known diffusion-limited dendritic growth, which occurs at much higher current density, the mossy growth process is vaguely described as “kinetically limited” in literature and its mechanism remains poorly understood. Recent study shows that the detachment of mossy filaments from substrate during electrostripping, which forms “dead lithium”, is a major cause of the battery capacity fading. A better understanding of the structure evolution of mossy deposits during cycling is therefore of considerable importance for developing successful strategies to improve the cycling life of metallic anodes.
In this study, we performed operando tomography of mossy zinc structure growth on Cu substrate during electrodeposition with nanoscale resolution at the National Synchrotron Light Source II. Zinc electroplating was carried out at a constant overpotential of 50mv in an in-situ electrodeposition cell made of a capillary tube with the working (Cu wire) and counter (Zn wire) electrodes inserted from opposite ends. Tomography datasets were collected every 2 minutes with an effective voxel size of 43 nm. The 3D structure of zinc deposits was reconstructed from the datasets using open-source code TomoPy.
Three different nucleation sites were observed, and the Zn mossy structure was divided into three groups according to these sites for a more detailed analysis. The calculated average porosity of the three mosses was ~35% and this was supported by ex-situ analysis. These three groups were separated into shells from their cores, and the most significant growth was occurring at the outermost shell. Further, the porosity and the volume of the inner shell and the core reached a steady state after a certain amount of time of electrodeposition. This result showed the penetration of the electrolyte to the inner parts of the mossy Zn was limited. All three mossy structure showed the same growth pattern without a preferred growth direction; however, there was an apparent difference of volume growth rate between them, indicating a possible diffusion limitation or uneven electric field distribution, which was in contrast with the previous studies. From ex-situ focus-ion beam scanning electron microscopy examination, it was shown that the moss structure was comprised of individual filaments, which repeatedly branched and entangled to form a mossy Zn.

Figure 1
(Physical and Analytical Electrochemistry Division David C. Grahame Award) My 54 Years of Doing Electrochemistry and What Is New
Authors: Parkinson Bruce Alan 
Published: July 2021

I am very honored to be selected to receive the David C. Graham Award from the Electrochemical Society, an award that has been bestowed on so many outstanding electrochemists over the years including many of my mentors. This symposium is also close to my 70th birthday and may then be near the end of attending ECS meetings. My talk will start with an acknowledgement that awards like this do not happen without the students, post docs and colleagues that have worked for me and with me over my 54 years of doing electrochemistry that started with science fairs in high school and is ending at the University of Wyoming. Ironically the first papers that I read when arriving in graduate school at Caltech were David Graham’s pioneering work on double layers at mercury electrodes that were very relevant to part of my PhD work on double layer effects on electron transfer kinetics at mercury electrodes. My post doc at Bell Labs introduced me to solid state science and semiconductor photoelectrochemistry as applied to solar energy conversion. These topics continued to interest me for the rest of my career in photoelectrochemistry but I was always interested in learning new things and attacking interesting problems and I will briefly review some of this work. These include research in the areas of UHV surface science, both developing and applying scanning probe microscopies, growth and applications of 2D materials (long before they became a trend) and even photoelectrochemical processes on the surface of Mars where we explained the photoelectrochemical origin of the high concentrations of perchlorate on the surface of Mars.
The rest of the talk will be concerned with an entirely new area for me, covalent organic framework (COF) materials applied to membranes applications, that has been a focus for the last few years. In this new project, a collaboration with colleagues at the University of Wyoming, involves developing two dimensional COFs with controllable sized hexagonal pores that we can functionalize with a wide variety of functional groups. We have been exploring applications of membranes constructed from these 2D-COFs for ion sieving based on size and charge, organic solvent separation and their antifouling abilities. Specifically, we have designed and tested a membrane constructed for a 2D-COF with pores that are lined with carboxylate groups that demonstrates a very specific size cut off for the conduction of a series of increasing sized tetraalkylammonium cations when paired with a polymeric anion that will not pass through the membrane. The stucture of this family of 2D-COFs is shown in the Figure. We have also demonstrated very high fluxes for organic solvent nanofiltration that is related to their polarity, size and hydrogen bonding properties. A future focus will be on developing a membrane that excludes small ions that will be useful in desalinization systems.

Figure 1
(Invited) Photoelectrode Materials Design for Solar Fuels: Where Are We Now?
Authors: Rajeshwar Krishnan 
Published: July 2021

Solar water splitting offers an attractive solution for renewable energy storage. Ternary metal vanadates have drawn attention for use in photoelectrochemical (PEC) water oxidation due to their low band gap and photostability.1 For example, Cu2V2O7 with a ratio of CuO: V2O5 stoichiometry (2:1) is a visible light active n-type semiconductor with a low band gap (see below), and has seen use in PEC devices because of its high stability for PEC water oxidation.2

This paper describes the development of a hybrid electrochemical/thermal route for the preparation of metal vanadate thin films. Electrodeposition is a facile, low temperature method which can be deployed to prepare thin films of a target semiconductor. Also, the optoelectronic parameters (e.g., photocurrent, flat band potential) of the thin film semiconductors prepared by electrodeposition can be measured easily without any more processing steps. In addition, the thickness of a given thin film semiconductor, a crucial factor for PEC reactions, can be controlled easily in an electrodeposition process.
A two-step electrodeposition strategy for ternary oxides3 was deployed in this study. Results will be presented for M-V-O ternary films (e.g., Cu2V2O7) on fluorine doped tin oxide (FTO) substrate. In the first step, a copper thin film was deposited cathodically from copper(II) nitrate in a non-aqueous medium to preclude copper oxide formation. In the second step, the copper thin film was stripped anodically in ammonium metavanadate (NH4VO3) aqueous solution to generate Cu+ and subsequent in situ precipitation with VO3
- species to yield a green CuVO3 film on the substrate. Electrochemical quartz crystal microgravimetry confirmed two- and one-electron stoichiometry for the first and second steps respectively.
Finally, aspects related to film stability and charge transfer efficiency as they relates to solar water splitting, will be reviewed in the light of data from our group.

References:

K. Rajeshwar, M. K. Hossain, R. T. Macaluso, C. Janáky, A. Varga, P. J. Kulesza, J. Electrochem. Soc.
2018, 165, H3192−H3206.

M. K. Hossain, P. Sotelo, H. P. Sarker, M. T. Galante, A. Kormányos, C. Longo, R. T. Macaluso, M. N. Huda, C. Janáky, K. Rajeshwar, ACS Appl. Energy Mater.
2019, 4, 2837-2847.

L. H. Antonia, N. R. de Tacconi, W. Chanmanee, H. Timmaji, N. Myung, K. Rajeshwar, Electrochem. Solid-State Lett.
2010, 13, D29-D32.