bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Capacity and High Rate Nasicon Naxv(Mn/Mg/Al)(PO4)3cathodes for Na-Ion Batteries
Authors: Ghosh Subham , Barman Nabadyuti , Senguttuvan Premkumar 
Published: July 2021

Electrochemical energy storage devices, particularly rechargeable batteries, are attractive solution to balance energy production of intermittent natural sources such as wind and solar. Despite its success in portable electronics market, Li-ion technology faces serious hurdle for grid storage application due to scarcity and geographical access of lithium sources. From the viewpoint of cost and abundance of raw materials, sodium ion batteries are appealing for grid storage application.1 Various classes of Na-ion electrode and electrolyte materials have been developed recently based on the know-how knowledge gained from Li-ion chemistry. However, the commercialization of NIBs has been impeded by the lack of high energy density cathodes. To this end, multi-electron based polyanionic cathodes are attractive, because of their high insertion voltages and storage capacities.2

Among the cathode materials, NASICON type cathodes with a general chemical formula NaxMM’(PO4)3(x= 2-4; M=V, Ti, Fe, Cr; Mʹ =Mn, Co, Mg, Fe) have garnered significant interest due to higher sodium ion conductivities as well as enhanced chemical and thermal stabilities.3 In this talk, we will present our recent studies on the impact of Mg2+ and Al3+ cationic substitution into the Na3V2(PO4)3 framework.4,5 The Mg- and Al-substituted NVMP cathodes exhibit smoother voltage profiles, facile sodium (de)intercalation, enhanced rate performances (80 mA h g-1 at 5C rate) and better capacity retention (~96% after 100 cycles) compared to the unsubstituted sample. Their improved performances are attributed to suppressed Jahn-Teller effect, enhanced covalent character and Na-ion vacancies created in the NASICON framework.
References:

N. Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Chem. Rev.
2014, 114, 11636.

C. Masquelier, L. Croguennec, Chem. Rev.
2013, 113, 6552.

R. Liu, Z. Liang, Z. Gong, Y. Yang, small methods
2019, 3, 1800221.

S. Ghosh, N. Barman, M. Mazumder, S. K. Pati, G. Rousse, P. Senguttuvan, Adv. Energy Mater.
2020, 10, 1902918.

S. Ghosh, N. Barman, P. Senguttuvan, Small
2020, 16, 2003973.

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Electrocatalytic Cross-Coupling Reactions Assisted By Redox-Active Mediators
Authors: Sevov Christo 
Published: July 2021

The seminar will detail electrocatalytic C–C and C–N bond-forming methodologies enabled by redox-active mediators and shuttles. Here, we will demonstrate a symbiotic relationship between energy storage and metal-catalyzed organic synthesis. Two research initiatives will be discussed that highlight the use of a mediator to (i) protect a coupling catalyst from overreduction through a degenerate shuttling of electrons and (ii) assist in oxidation of complexes with slow ET kinetics under electrochemical conditions.
The concept of protecting catalyst from degradation using shuttles will be discussed in the context of cross-electrophile coupling (XEC). Couplings of alkyl and aryl halides promoted by electrochemistry represents an attractive alternative to conventional methods that require stoichiometric quantities of high-energy reductants. Most importantly, electroreduction can readily exceed the reducing potentials of chemical reductants to activate catalysts with improved reactivities and selectivities that are otherwise incompatible with conventional reductants. This work details the mechanistically-driven development of an electrochemical methodology for XEC that utilizes redox-active shuttles developed by the energy-storage community to protect reactive coupling catalysts from overreduction. The resulting electrocatalytic system is practical, scalable, and broadly applicable to the reductive coupling of a wide range of aryl, heteroaryl, or vinyl bromides with primary or secondary alkyl bromides. The impact of overcharge protection as a strategy for electrosynthetic methodologies is underscored by the dramatic differences in yields from coupling reactions with added redox shuttles (generally >80%) and those without (generally <20%). In addition to excellent yields for a wide range of substrates, reactions protected from overreduction can be performed at high currents and on multigram scales
The second half of the talk will demonstrate the use of mediators to protect ligandless complexes that are susceptible to electroplating on a cathode and to facilitate oxidation of the electrochemically-inactive catalysts to the active form. This strategy is applied to an electrochemically driven, scalable Chan-Lam-Evans reaction that utilizes simple copper salts to promote C-N bond formation under an inert atmosphere. This work represents a rare example of air-free CLE coupling. This oxidative reaction is performed in an undivided cell with a simple Cu salt that would otherwise rapidly plate out of solution. Mediator-assisted CLE coupling provides access to a broad range of amine products that are otherwise challenging to form even in air. The methodology seeks to eliminate the need for O2 on scale and provide an attractive alternative for process groups in industry.
Continuous Stirred Tank Electrochemical Reactor for High-Throughput Synthesis
Authors: Graaf Matthew 
Published: July 2021

Flow electrolysis has been a crucial component for enabling large-scale applications of organic electrochemical transformations outperforming batch electrolysis. To-date, these applications have mainly focused on microchannel or parallel-plate style reactors1. Although having established numerous examples of successfully performing electrolyses on lab and commercials-scales2, the nature of these reactors often requires recirculating conditions rendering them as semi-batch and sometimes limiting through-put or product quality. This presentation with discuss a modular continuous stirred tank reactor capable of single-pass reactivity to provide multi-kilogram per day throughput and high-product quality with minimal reactor footprint.
References:
[1]: Pletcher, D., Green, R., Brown, R.; Chemical Reviews., 2018, 118, 4573
[2]: Cardoso, D., Sljukic, B., Santos, D., Sequeira, C.; OPRD, 2017, 21, 1213

Matthew Graaf is an employee of AbbVie and may own AbbVie stock. AbbVie sponsored and funded the study; contributed to the design; participated in the collection, analysis, and interpretation of data, and in writing, reviewing, and approval of the final publication.
Selective Aryl-Nitro Reduction of Pharmaceutical Intermediates
Authors: Graaf Matthew 
Published: July 2021

Hydrogenation of nitro groups to produce anilines is a well-established transformation in organic chemistry and the pharmaceutical industry [1]. However, high pressure hydrogenations can be hazardous at multi-kilo scales and functional group compatibly is often problematic for pharmaceutical intermediates requiring a specialized catalyst [2]. In a continued effort to promote electrochemistry in pharma as a greener and safer alternative, an improved method of electrochemically producing anilines has been achieved. In this presentation, the development of a robust and efficient undivided Aryl-nitro reduction will be discussed.
References:
[1]: Jones, W.; Platinum Metals Rev., 1958, 2, 86
[2]: Blaser, H-U., Steiner, H., Studer, M.; ChemCatChem., 2009, 1, 210

Matthew Graaf is an employee of AbbVie and may own AbbVie stock. AbbVie sponsored and funded the study; contributed to the design; participated in the collection, analysis, and interpretation of data, and in writing, reviewing, and approval of the final publication.

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Bioelectrocatalytic Conversion of N2: From Chemically Inert Gas to Chiral Chemicals
Authors: Chen Hui , Minteer Shelley D. 
Published: July 2021

Dinitrogen molecule (N2) is the most abundant natural gas and also the ultimate source of nitrogen for nitrogenated industrial and natural compounds. So far, the fully hydrogenated product, ammonia (NH3), is the most common product of N2 fixation.1 However, NH3, the regular end-product of N2 fixation, is a bulk chemical with low added-value. The conversion of NH3 to nitrogenous compounds with high added-value and complicated structure still requires further tedious chemical synthesis with the use of precious metal catalysts.2 In our study, an upgraded N2 fixation system was firstly designed and constructed based on a bioelectrocatalytic N2 reduction architecture.3 The NH3 generated via N2 reduction catalyzed by nitrogenase was in situ utilized by L-alanine dehydrogenase to realize the reductive amination of pyruvate and the generation of alanine. The reduced equivalent to support the N2 reduction and reductive amination of pyruvate was regenerated by the electrochemical method. ω-TA transferred the amino group from alanine to ketone substrates and finally produced desired chiral amine intermediates.4 On this basis, an H2 fuel cell module was integrated into the upgraded N2 fixation system to construct a self-powered H2/α-keto acid fuel cell. In the new system, the upgraded N2 fixation was powered by the oxidation of H2 with high Faradaic efficiency and without the requirement of external electrical energy input.5 Finally, the end-product of N2 fixation in our study successfully went beyond NH3 and reached high-value-added chiral amine intermediates and chiral amino acids. The produced chiral amine intermediates and chiral amino acids have wild application in pharmaceuticals production and biotechnology research.

References

(1) Foster, S. L.; Bakovic, S. I. P.; Duda, R. D.; Maheshwari, S.; Milton, R. D.; Minteer, S. D.; Janik, M. J.; Renner, J. N.; Greenlee, L. F. Catalysts for nitrogen reduction to ammonia. Nat. Catal.
2018,
1, 490.
(2) Balaraman, E.; Srimani, D.; Diskin-Posner, Y.; Milstein, D. Direct synthesis of secondary amines from alcohols and ammonia catalyzed by a ruthenium pincer complex. Catal. Lett.
2015,
145, 139-144.
(3) Milton, R. D.; Cai, R.; Abdellaoui, S.; Leech, D.; De Lacey, A. L.; Pita, M.; Minteer, S. D. Bioelectrochemical Haber-Bosch Process: An Ammonia-Producing H2/N2 Fuel Cell. Angew. Chem. Int. Ed.
2017,
56, 2680-2683.
(4) Chen, H.; Cai, R.; Patel, J.; Dong, F.; Chen, H.; Minteer, S. D. Upgraded Bioelectrocatalytic N2 Fixation: From N2 to Chiral Amine Intermediates. J. Am. Chem. Soc.
2019,
141, 4963-4971.
(5) Chen, H.; Prater, M. B.; Cai, R.; Dong, F.; Chen, H.; Minteer, S. D., Bioelectrocatalytic Conversion from N2 to Chiral Amino Acids in a H2/α-Keto Acid Enzymatic Fuel Cell. J. Am. Chem. Soc.
2020,
142 (8), 4028-4036.
(Invited) High-Quality Protonic Diodes and Their Transformation into Solar Cells and Conductors
Authors: Schulte Leanna , McClarin Geoffrey R. , White William , Renna Lawrence A. , Ardo Shane 
Published: July 2021

Ionically conductive materials and diodes have been actively studied since the pioneering work of John Bockris in 1959. The subset of purely protonic diodes based on liquid water are far less common, yet are more analogous to electronic semiconductors in that generation, recombination, and transport each occur and junctions fully equilibrate.
In my presentation, I will explain how water is a protonic semiconductor and show that it can be doped through addition of salts of H+ and/or OH– that when fixed in place using polymeric bipolar membrane scaffolds enable purely protonic diodes. Electrochemical evaluation is achieved using membrane–electrode–assemblies that drive reversible H2 redox chemistry to transduce changes in electronic electrochemical potential into protonic electrochemical potential, and vice versa. Characterization of the semiconducting properties of these protonic diodes allowed for determination of flatband potentials using Mott–Schottky analysis, and mobilities via analysis of space-charge-limited conduction.
Further, via covalent modification of polymers with photoacid dye sensitizers we were able to demonstrate solar cell function, and modification with generation/recombination buffering groups we were able to demonstrate ohmic conduction. The latter is relevant for application of bipolar membranes in CO2 electrolyzers. Collectively, these efforts form the foundational framework for new devices and functions that benefit from purely protonic transport.
(Invited) Water Dissociation Catalysis in Bipolar Membranes and in Electrocatalysis
Authors: Boettcher Shannon W. 
Published: July 2021

Water is arguably humanity’s most-important molecule due to its ubiquitous role in biological, industrial, and environmental processes. Reactions of water typically involve breaking H-O bonds. The simplest reaction is heterolytic water dissociation (WD), H2O -> H+ + OH-, the understanding of which has been one focus of experiment and theory for decades. WD is also a fundamental elementary step in many electrochemical processes. For example, the WD step is thought rate-limiting for the hydrogen-evolution reaction (HER) under alkaline conditions and modification of Pt surfaces with metal hydroxides, which presumably accelerate WD, increase HER activity. While measurements of dissociative water adsorption are often made using surface-science tools in vacuum, the WD reaction is remarkably poorly understood under electrochemical conditions.
We use a bipolar-membrane (BPM) electrolyzer, where WD is driven in the region between a hydroxide-exchange and proton-exchange membrane by an applied potential, to study WD kinetics across a range of materials.1 We find that the local pH is a critical, but previously unrecognized, variable affecting WD kinetics and propose a pH-dependent proton-transfer WD mechanism. Combining WD catalysts efficient in acidic and basic conditions nearly eliminates the WD overpotential in BPM electrolyzers operating at 20 mA cm-2 and enables BPM operation at 0.5 A cm-2 with a total applied electrolysis potential of ~ 2 V. These values are substantial improvements over the state of the art and enable new applications for BPMs. We further discovered that the WD kinetics measured in the BPM correlate with HER kinetics under conditions where WD is an important elementary step and illustrate the design of ‘bifunctional’ electrocatalysts based on insight into the underlying WD steps.

1Oener, S. Z.; Foster, M. J.; Boettcher, S. W., Accelerating water dissociation in bipolar membranes and for electrocatalysis. Science
2020, DOI: 10.1126/science.aaz1487

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Introducing the Virus Bioresistor: A New Electrochemical Biosensing Paradigm
Authors: Penner Reginald M. 
Published: July 2021

Viruses are infamous for making us sick. That’s their dark side. But they don’t receive enough credit for the good they can do. Specifically, they can be convinced to collaborate with us to acquire information from bodily fluids about early stage diseases – and in particular, cancers. You already know that for many cancers, early detection means a cure is possible, even likely.
Together with a chemical biologist at UCI, Professor Greg Weiss and his team, our research group is designing a new type of biosensor that communicates electrically with viruses in order to diagnose bladder cancer, and to detect its recurrence in patients who have had it in the past. These biosensors are called Virus BioResistors or “VBRs”. A VBR will be capable of detecting early stage bladder cancer in a routine urinalysis test, in 5 min. or less, in a doctor’s office. This transformational capability has the potential to save lives. Bladder cancer is the “low hanging fruit” for this technology because it is the easiest cancer to detect in urine. But the possibility exists to develop VBRs capable of detecting several other cancers using urinalysis including cancers of the prostate, kidney, and possibly even pancreas.
How does it work? The VBR depends upon an electrodeposited bioaffinity layer, ≈100 nm in total thickness, that is a composite of PEDOT (poly(3,4-ethylenedioxythiophene)) and the M13 virus particles that serve as receptors. The impedance of this layer is measured using two gold electrodes. At low frequencies, this impedance increases when target protein molecules are bound within the PEDOT-virus layer. The high frequency impedance measures only the electrical conductivity of the solution, providing information on the hydration state of the patient undergoing testing. The orthogonality of the VBR response at low and high frequencies allows accurate measurement of target protein, without influence from the salt concentration of urine – an important capability for clinical applications of this technology. Other secrets of the VBR will be revealed in this presentation.

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Electrochemical Surface Oxidation Enhanced Raman Scattering on Cu
Authors: Cheuquepan William , Perez-Estebañez Martin , Hernandez Sheila , Heras Maria Aranzazu , Colina Alvaro 
Published: July 2021

One of the main characteristic of Analytical Chemistry is a constant searching for new methodologies to overcome analytical problems. Minimization of analysis time and sample volumes, replacement of extensive extraction protocols and improvement of selectivity are common tasks in analytical research all around the world. Spectroelectrochemistry is an instrumental technique that totally represents this spirit: The combination of electrochemical set-ups with spectroscopy techniques to study the surface processes has shown to be a powerful technique to resolve complex mixtures of molecules, where analytical signals can present severe interferences [1].
Spectroelectrochemistry has been demonstrated to be a powerful analytical technique to study adsorption processes and molecular reactivity on electrode surfaces. More specifically, Raman spectroelectrochemistry (Raman-SEC) combined with plasmonic structures has been demonstrated to be an excellent tool to study molecules at low concentration thanks to Surface Enhanced Raman Scattering (SERS) phenomenon. [2].
For almost half a century, Raman-SEC has broadly studied the properties of SERS substrates developed with nanoparticles of plasmonic metals, such as silver, gold and copper, focusing its efforts on the characterization of nanostructures morphology.
In 2018, our group discovered a novel methodology to enhance the Raman signal during the electrochemical oxidation of silver electrodes in acidic media [3]. We denoted this phenomenon as Electrochemical Surface Oxidation Enhanced Raman Scattering (EC-SOERS), and represents a phenomenon similar to SERS, because of the enhancement of the Raman signal, but contrary to SERS, since it suggests the loss of plasmonic properties (and thus, Raman enhancement) of metallic structures during the electrochemical oxidation of the plasmonic nanostructures.
In this communication, we demonstrate, for the first time, that EC-SOERS can be observed on copper electrodes. This metal, known for its SERS properties, can be also used to enhance selectively the Raman signal during its electrochemical oxidation, detecting different organic molecules with a wide variety of functional groups, opening new gates towards the development of new analytical tools based on EC-SOERS.
First-Principles Modeling of the Electrochemical Kinetics at Solid-Water Interface
Authors: Zhao Xunhua , Liu Yuanyue 
Published: July 2021

Kinetic information, such as the activation energy and transition state, is critical to understanding the reaction. However, the kinetic information of electrochemistry at solid-water interface is challenging to obtain from conventional models of density functional theory (DFT), as they often neglect the presence and/or the dynamics of the surface charge [1] and the solvent configuration, which are further coupled. Here we present a new model that accounts for these effects, by combining hybrid solvation, constant-electron-potential, and slow-growth sampling techniques together. We then apply this model to elucidate the active site structure and the mechanism of electrochemical carbon dioxide reduction catalyzed by single-nickel-atom embedded in graphene, which shows high performance in experiments while is not well understood [2].
[1] D. Kim, J. Shi, Y. Liu, J. Am. Chem. Soc. 2018, DOI: 10.1021/jacs.8b03002
[2] X. Zhao, Y. Liu, J. Am. Chem. Soc. 2020, DOI: 10.1021/jacs.9b13872
A Soft On/Off Switch Based on the Electrochemically Reversible H-J Interconversion of a Porphyrin Membrane at an Electrified Liquid|Liquid Interface
Authors: Scanlon Micheal D. , Molina-Osorio Andrés F. , Yamamoto Sho , Nagatani Hirohisa 
Published: July 2021

Soft molecular assemblies that respond reversibly to external stimuli are attractive materials as on/off switches, in optoelectronic, memory and sensor technologies. In this presentation, the reversible structural rearrangement of a soft porphyrin membrane under an electrical potential stimulus in the absence of solid-state architectures will be presented.
The free-floating porphyrin membrane lies at the interface between immiscible aqueous and organic electrolyte solutions and is formed through interfacial self-assembly of zinc(II) meso-tetrakis(4-carboxyphenyl)porphyrins (ZnPor). A potential difference between the two immiscible electrolyte solutions induces the intercalation of bis(triphenylphosphoranylidene)ammonium cations from the organic electrolyte that exchange with protons in the porphyrin membrane. In situ UV/vis absorbance spectroscopy shows that this ionic intercalation and exchange induces a structural interconversion of the individual porphyrin molecules in the membrane from an H- to a J-type molecular configuration. These structural rearrangements are reversible over 30 potential cycles. In situ polarisation-modulation fluorescence spectroscopy further provides clear evidence of structural interconversion of the porphyrin membrane, as intercalation of the organic electrolyte cations significantly affects the latter’s emissive properties. By adjusting the pH of the aqueous phase, additional control of the electrochemically reversible structural interconversion can be achieved, with total suppression at pH 3.
The work presented herein opens new opportunities to investigate the use of structurally dynamic soft supramolecular porphyrin assemblies at the interface between two immiscible electrolyte solution (ITIES) as switchable on/off responsive nanomaterials, with applications in optoelectronic, memory and sensor devices.

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