bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Atomically Dispersed Transition Metal Centers for the Electrochemical Nitrate Reduction Reaction Towards Ammonia Synthesis
Authors: Murphy Eamonn , Liu Yuanchao , Matanovic Ivana , Ly Alvin , Huang Ying , Guo Shengyuan , Wang Hanson , Zenyuk Iryna V. , Spoerke Erik D. , Atanassov Plamen 
Published: July 2022

The electrochemical reduction of oxidized nitrogen species, nitrate (NO3
-) and nitrite (NO2
-), both of which are environmental pollutants, to benign nitrogen gas (N2) has been extensively researched for water remediation applications. Recently, a large research focus has shifted to reducing these oxidized nitrogen species to ammonia (NH3).1 In this way, a dual benefit is achieved by eliminating the environmentally hazardous nitrates, while also creating a value-added product, ammonia. Moreover, the nitrate reduction reaction (NO3RR) can aid in closing the nitrogen cycle, by reforming nitrates introduced into the environment through nitrate-based fertilizers originating from the Haber-Bosch process, back into NH3, in a carbon neutral fashion.
The NO3RR is a complex, 8e-, 9H+ transfer process with multiple possible intermediate species (NO2
-, NO, N2O, N2H4, NH2OH, NH3) and rate limiting steps. The NO3RR mechanism and its activity descriptors over various metals is not fully understood, and this is especially true over atomically dispersed sites, where less than a handful of studies exist.2,3 Our previous work found that atomically dispersed nitrogen coordinated Fe-N4 and Mo-N4 sites displayed distinct associative adsorption and dissociative adsorption of the nitrate molecule in the NO3RR pathways, respectively. Specifically, Fe-N4 sites adsorb and reduce NO3
- into NH3through an 8e- pathway on the surface, while Mo-N4 sites dissociate NO3
- and release NO2
- into the bulk electrolyte. These active sites were then integrated into a single bi-metallic catalyst (FeMo-N-C), creating a catalytic cascade yielding a significantly improved yield rate and Faradaic efficiency for NH3.4

In this talk, building on our previous work, we will present a series of transition metal atomically dispersed nitrogen doped carbon (M-N-C) electrocatalysts (M = Mn, Fe, Co, Ni, Cu...) for the systematic investigation of NO3RR activities over the different metal centers. In this work we leverage physical (ICP-MS, gas physisorption), electrochemical (e.g., NO3RR) and computational (DFT) characterization to create a set of NO3RR activity descriptors. A detailed set of activity descriptors can aid in the selection of atomically dispersed metals for creating efficient reaction cascades to synergize favorable reaction pathways.

Figure 1
(Digital Presentation) Interface Engineering of Transition Metal-Selenide Heterostructures for Application in Electrochemical Water-Splitting
Authors: Velpandian Muthuraja , Meduri Praveen 
Published: July 2022

Transition metal selenides (TMS) have sparked great interest in energy storage and catalysis because they are direct bandgap materials, have a highly layered structure, high redox activity, abundant active sites at the edges, short diffusion paths, and large surface area1. However, low electrical conductivity and structural instability result in long-term performance degradation. The development of high-performance water electrolyzers and metal-air batteries requires the design and construction of efficient TMS electrocatalysts. In order to boost electrochemical activity, increasing emphasis has been devoted to interface engineering of TMS heterostructures through manipulation of composition, adjustment of crystal facets, and heteroatomic doping2. Interface engineering helps in optimizing reaction intermediates, modulating charge carrier characteristics, and preventing the aggregation of active components. Herein, we designed and studied the interface between hydrothermally synthesized tin selenide (SnSe2) and tungsten selenide (WSe2). The intimate electronic interaction between the bimetallic selenides leads to a rich interface boundary that reduces the surface energy and creates a larger number of active sites involved in both the hydrogen evolution and oxygen evolution reactions3. These heterostructures exhibited a low overpotential of 180 mV at 10 mA cm-2 and good stability of up to 12 hours for the hydrogen evolution reaction, and a low overpotential of 250 mV at 10 mA cm-2 and stability up to 12 hours for the oxygen evolution reaction. This study gives a better insight into the design of TMS heterostructures using interface engineering for high electrocatalytic activity.
References:
(1) Gbadamasi, S.; Mohiuddin, M.; Krishnamurthi, V.; Verma, R.; Khan, M. W.; Pathak, S.; Kalantar-Zadeh, K.; Mahmood, N. Interface Chemistry of Two-Dimensional Heterostructures – Fundamentals to Applications. Chem. Soc. Rev.
2021, 50 (7), 4684–4729. https://doi.org/10.1039/D0CS01070G.
(2) Zhao, R.; Li, Q.; Jiang, X.; Huang, S.; Fu, G.; Lee, J.-M. Interface Engineering in Transition Metal-Based Heterostructures for Oxygen Electrocatalysis. Mater. Chem. Front.
2021, 5 (3), 1033–1059. https://doi.org/10.1039/D0QM00729C.
(3) Chen, P.; Tong, Y.; Wu, C.; Xie, Y. Surface/Interfacial Engineering of Inorganic Low-Dimensional Electrode Materials for Electrocatalysis. Acc. Chem. Res.
2018, 51 (11), 2857–2866. https://doi.org/10.1021/acs.accounts.8b00266.
(Digital Presentation) Electrochemical and UV-VIS Spectroscopic Studies of Bismuth(III) Interactions with L-Cysteine
Authors: Schlessman Jamie , Huang Jonathan , Cheek Graham 
Published: July 2022

Introduction
In an ongoing investigation of the interaction of bismuth(III) compounds with L-cysteiene1, recent work has involved more complete characterization of these interactions at lower pH levels in various aqueous media. Pharmaceutical medications2 such as bismuth subsalicylate (BSS) and bismuth citrate (BC) have now been investigated at pH 1.00 and 3.00 by both cyclic voltammetric and UV-VIS methods. Electrochemical methods have been used to evaluate the interaction of L-cysteine with bismuth compounds by observing shifts in the potential for bismuth reduction, and UV-VIS methods have allowed the observation of an absorbance peak at approximately 340 nm due to the bismuth(III) ion interaction with the L-cysteine thiol group.
Results and Discussion
Recent work has involved investigation of bismuth(III) nitrate (BN), BSS, and BC with L-cysteine at pH 1.00 and 3.00 in both HNO3 and HCl solutions. In general, complexation of BN is not quite as favorable at lower pH levels as in pH 7.00 MOPS (3-N-morpholino)propanesulfonic acid)3 buffer solution.1 This conclusion was based on the need for higher mole ratios of L-cysteine to BN to achieve the final state of the voltammograms. The UV-VIS behavior was also not as well-defined as in our previous work1, with higher molar ratios of L-cysteine needed to produce the 340 nm absorbance peak. These results support the competition of protons with bismuth(III) for the L-cysteine ligand, there being much higher proton levels at pH 1.00 and pH 3.00 than at pH 7.00. The behaviors of BC and BSS at pH 1.00 and pH 3.00 are in many ways similar to that of BN. Finally, some preliminary work on glutathione (cysteine-containing tripeptide) interactions with bismuth compounds is also planned for presentation.
References

T. Cheek and D. Peña, J. Electrochem. Soc.,
167, 155522 (2020)

Li, R. Wang, and H. Sun, Acc. Chem. Res.,
52, 216 (2019).

M. H. Ferreira, I. S. S. Pinto, E. V. Soares, and H. M. V. M. Soares, RSC Advances, 5(39), 30989 (2015).
(Organic and Biological Electrochemistry Division Manuel M. Baizer Award) A Perspective on Organic Electrochemistry
Authors: Little Dan 
Published: July 2022

Manuel Baizer’s profound influence upon electrochemistry is undeniable. He was a pioneer and a visionary whose influence and insights continue to permeate scientific thought.
During his lifetime Baizer frequently expressed frustration at the slow pace at which electrochemistry’s attributes were accepted and utilized by the broader community of organic chemists. Even now, despite a tremendous surge and a steady increase in the number of researchers who are exploring the breadth of the field, the rate of its inclusion in textbooks lags far behind – a situation that appears to be on the cusp of a most appropriate change.
I was fortunate to have Manuel Baizer as my colleague at UCSB. His optimism, drive, curiosity and interest in the field was contagious. Without doubt, his arrival on the UCSB campus provided the spark needed to turn my passing interest into action. Several co-directed students and research projects resulted including, for example, work involving electrogenerated bases, the generation and utilization of superoxide, as well as various intramolecular electroreductive processes and their application to the total synthesis of natural products.
Today’s presentation will focus upon examples of these efforts and will then turn to ongoing research in the area of mediated electron transfer chemistry.
Electrochemically Generated Periodates As a Platform Oxidizer
Authors: Waldvogel Siegfried R 
Published: July 2022

Periodates represent one of the most powerful and versatile oxidizers in organic synthesis. Common ways to generate it electrochemically employ lead dioxide anodes. The disintegration of these electrodes cause contaminations which impede sensitive applications.[1] The purification of periodates makes this reagent usually too costly for pharmaceutical applications. With the use of boron-doped diamond anodes, a direct conversion of the inexpensive sodium and potassium iodide within an eight-electron oxidation process renders periodate. The novel process is scalable, heavy metal-free and can be conducted in batch as well as flow electrolyzers.[2] This approach can also be used for the regeneration of periodates from iodates and other iodine sources (waste streams). The process was implemented in a new synthetic approach to levetiracetam, which demonstrates the technical application and recycling of iodates in API synthesis.[3] This reagent can also be employed to make sulfoximines and degrade lignins to elaborated building blocks. [4] The reactor concepts for the efficient preparation of multi-kg quantities will be presented.
References:
[1] D. Pollok, S. R. Waldvogel, Chem. Sci. 11 (2020) 12375–12592.
[2] S. Arndt, D. Weis, K. Donsbach, S. R. Waldvogel, Angew. Chem. Int. Ed.
132
,
(2020) 8112-8118.
[3] S. Arndt, B. Grill, H. Schwab, G. Steinkellner, U. Pogorevčnik, D. Weis, A. M. Nauth, T. Opatz, K. Donsbach, S. R. Waldvogel, M. Winkler, Green Chem. 23 (2020) 388–395.
[4] M. Klein, S. R. Waldvogel, Angew. Chem. Int. Ed. 60 (2021) 23197–23201.
(Digital Presentation) Wavelength Controllable Multi-Color Firefly Luciferin Analogues
Authors: Kitada Nobuo , Kamiya Genta , Moriya-Saito Ryohei , Iwano Satoshi , Obata Rika , Hirano Takashi , Maki Shojiro 
Published: July 2022

I will show you the multi-color luciferin analogues, and in particular the usefulness of near-infrared(NIR) luciferin analogues.
Firefly bioluminescent reaction requires luciferin, luciferase, Mg2+, ATP and O2, and emits light at 560 nm (green-yellow light). As the light emission efficiency of the firefly bioluminescence system is extremely high(ΦBL=41%), this system is attracting widespread attention as a bioimaging tool.
We have studied the relationship between structure modification and the firefly luminescence wavelength, where the luciferase of Photinus pyralis (Ppy) was used. As a result, we are able to control the wavelength of the luciferin analogues to some extent. An analog having the thiazoline ring connected directly to p-(dimethylamino)phenyl group exhibited blue shifted luminescence maximum. Furthermore, replacement of the dimethylamino group into a hydroxyl group caused blue shift of luminescence wavelength. On the other hand, Introduction of a double bond between the thiazoline ring and the benzene ring caused large red shift of luminescence wavelength.
Based on these structure-activity relationships, we have synthesized a number of luciferin analogs. The shortest emission wavelength of luciferin analogs is 430 nm, and the longest is 760 nm by using Ppy luciferase. Among them, near-infrared(NIR) light is expected to be applied to in vivo imaging because of its high living body permeability.
Therefore, Thus, AkaLumine, a luciferin analogue that produces light at 675 nm wavelength, was developed. This compound was shown to yield useful results when applied to the in vivo imaging of mice. We have improved the characteristics of AkaLumine to optimize this compound for use in in
vivo imaging, thus obtaining the compounds dubbed TokeOni and seMpai. In this way, bioluminescence imaging technology is undergoing constant innovation, and we continue to develop NIR luciferin analogues that can be used as imaging tools.
In this conference, I will present the characteristics of recently developed multi-color luciferin analogues, include NIR luciferin analogues.

Figure 1
(Invited, Digital Presentation) Tafel Analysis Algorithm: Objective Identification of the Linear Region
Authors: Leddy Johna , Coduto Joshua Richard 
Published: July 2022

Electrocatalysts for hydrogen evolution and oxidation (HER and HOR) reactions, oxygen reduction and evolution (ORR and OER) reactions, and carbon dioxide reduction reactions (CO2RR) are evaluated by Tafel analysis. The Tafel equation specifies the log-linear relationship between current and overpotential 𝛈. Heterogenous electron transfer parameters of exchange current density j
o and transfer coefficient 𝛂 are found. Standard heterogenous electron transfer rate k
0 can be found from j
o.
Conventionally, Tafel analysis is an extension of the Butler-Volmer equation applied at high overpotentials but where mass transport is not significant and the reverse reaction rate is negligible. Applicable at high 𝛈 when electron transfer rates are slow, kinetic parameters are extracted by linear regression. The conventional method is, however, subject to inaccuracies because the linear region is often determined subjectively, without attention to the constraints on overpotential range, no mass transport limitations, and low j
o.
An algorithm is developed to automate Tafel analysis with the objective to increase measurement accuracy and decrease subjective identification of the linear region. From linear sweep voltammograms (LSVs), j
o and α are determined from Tafel slopes in the best fit, linear range.
Comparisons of kinetic parameters between conventional and algorithmic Tafel analyses are made for the hydrogen evolution reaction (HER, 2H+ + 2e- ⇌ H2) on various unmodified electrodes and electrodes modified with Nafion® composites. The algorithmic Tafel analysis parameters correlate well with conventional Tafel analyses that respect constraints on mass transport, 𝛈, and j
o. Similar agreement is observed between literature and algorithmically fitted kinetic parameters for different electrochemical systems. The algorithm allows for straightforward, rapid Tafel analysis for improved measurement of rate parameters that is independent of user bias in selection of the linear region.

Acknowledgments

This work was supported by the Army Research Office.
(Invited) Towards a FRET Based DNA SAM Biosensor for Detection of Nucleic Acids
Authors: Grzedowski Adrian , Bizzotto Dan 
Published: July 2022

Rapid and sensitive detection of nucleic acids is an essential tool in many medical and clinical settings, that allows for fast diagnosis of bacterial and viral infections. Here, we present a DNA FRET-based biosensor to detect a hybridization event on a DNA SAM on gold surface. The monolayer was prepared by a potential assisted thiol exchange deposition, which provides better control over the surface coverage and its uniformity1. Our approach relies on a change in FRET (Förster Resonance Energy Transfer) signal caused by variations in distance between fluorophores. FRET imaging is a well-known, very sensitive technique, used commonly in many areas of chemistry and microbiology. FRET signal depends strongly on the distance between an acceptor and a donor fluorophore. It is an excellent tool to analyze small changes in DNA distance between adjacent strands and the surface2. Metal quenching also plays a major role, since fluorescence is strongly dependent on the distance from the metal surface3, which is an efficient quencher. Fluorophores, both acceptor and donor, are quenched significantly by the gold surface, this however, decreases substantially as the distance increases between the surface and fluorophore. As DNA is binding its complementary strands, the distance between the surface and the fluorophore labelled end increases.
Using a self-assembly property of thiols on gold surface, we show that mixed ssDNA SAM composed of two strands of thiolated ssDNA, each labelled with a different FRET fluorophore, gives an 8-to-10-fold signal enhancement, upon DNA hybridization (see figure 1). Binding of a complementary strand rigidifies the adsorbed DNA structure, and as a result we observe the increase in signal due to weaker gold quenching and shorter distance between FRET participating fluorophores. Moreover, by utilizing a single crystal electrode, we can study different surface concentration regimes and fluorescence signal increases, based on surface crystallography and the electrode potential.
(1) Leung, K. K.; Gaxiola, A. D.; Yu, H.-Z.; Bizzotto, D. Tailoring the DNA SAM Surface Density on Different Surface Crystallographic Features Using Potential Assisted Thiol Exchange. Electrochim. Acta
2018, 261, 188–197. https://doi.org/https://doi.org/10.1016/j.electacta.2017.12.114.
(2) Verhaven, A.; Doneux, T.; Bizzotto, D. Application of FRET Microscopy to the Study of the Local Environment and Dynamics of DNA SAMs on Au Electrodes. Langmuir
2018, 34 (49), 14802–14810. https://doi.org/10.1021/acs.langmuir.8b02131.
(3) Casanova-Moreno, J.; Yu, Z. L.; Massey-Allard, J.; Ditchburn, B.; Young, J. F.; Bizzotto, D. Luminescence in Electrochemistry; Springer International Publishing: Cham, 2017; pp 21– 77.

Figure 1
Highly Efficient Multi-Atom Pt and PtRu Catalysts for Anion Exchange Membrane Fuel Cells
Authors: Adabi Firouzjaie Horie , Shakouri Abolfazl , Williams Christopher , Regalbuto John R , Mustain William Earl 
Published: July 2022

During the last decade, anion exchange membrane fuel cells (AEMFCs) have gained popularity due to their
promise to provide low cost, high efficiency, high power density, and zero-emissions. Recent years have seen
a significant increase in the achievable peak power density and lifetime of AEMFCs, though that performance
has come with high loadings of Pt and PtRu catalysts at the cathode and anode, respectively1,2
. However, to displace incumbent proton exchange membrane fuel cells (PEMFCs), AEMFCs must be able to offer much
lower cost3,4. Therefore, the U.S. Department of Energy (DOE) recently set some challenging activity targets
for AEMFCs5; including a near-term target platinum group metal (PGM) loading of 0.2 mg/cm2 by 2023, 0.125
mg/cm2 by 2024 and zero PGM by 2030.
Recently, various efforts have sought to reduce the PGM loading in operating AEMFCs. Some efforts have
focused on developing completely PGM-free catalysts, such as Fe-N-C at the cathode6
. However, the nearterm DOE targets can be met by reducing the loading of existing catalysts, which can be accomplished by
maximizing metal utilization7. One effective strategy is to improve the mass activity of Pt by increasing the
number of active sites through catalyst size or structure control or improving the intrinsic activity of Pt through
the manipulation of its electronic structure. One approach that can be used to reduce the PGM loading is to
create atomically-dispersed catalysts. This can include single atoms or small multi-atom clusters 8,9
.
Therefore, in this work, Pt/C, Pt/NC, PtRu/C and PtRu/NC were fabricated using a simple, and scalable Switch
Solvent Synthesis (SWISS) method. This method synthesizes a high density of multi-atom catalysts. It is able
to do so by limiting the amount of water that is hydrating the synthesis precursors, which allows for
agglomeration to be limited. The catalysts were physically characterized using a wide array of techniques
including x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy
(TEM), and high-resolution Cs aberration-corrected scanning transmission electron microscopy (STEM). The
catalysts were also tested for their oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR)
activity in a rotating disk electrode setup. Their in-situ behavior was also investigated operating AEMFCs.
With this new generation of low-PGM materials, it was possible to reduce the PGM loading by factor of 12
while achieving comparable performance to commercial catalysts. Also, to assemble a cell with ultralow PGM
loading, our previously developed Fe–N–C cathodes6 were paired with a low-loading PtRu/NC anodes (0.05
mg PtRu per cm2, 0.08 mg Pt per cm2), which allowed for the demonstration of a specific power of 25 W per mg PGM (40 W per mg Pt).
Discrete Modeling of Ionic Space Charge Zones in Solids
Authors: Xiao Chuanlian , Chen Chia-Chin , Maier Joachim 
Published: July 2022

In this contribution discrete modeling of space charge zones in solids is presented, which is a sensible approach for handling pronounced space charge potentials as well as non-idealities in realistic solid state system1. At interfaces in charge-carrier containing systems, individual charge carriers redistribute, which leads to transport but also storage anomalies2. Such space charge zones are usually described by a continuum picture based on classic Gouy-Chapman (or Mott-Schottky) models. In addition to issues of internal consistency, this continuum approach is questionable if extremely steep profiles close to the interface occur, and analytical corrections are not very helpful. We show how discretization remedies a variety of such short-comings, allows for a straightforward taking account of non-idealities, and even provides surprising insight into double layer capacitance and conductance effects. Combining discrete modeling with the continuum description provides a particularly powerful method with the help of which non-idealities in the first layers (variation in structure, elastic effects, saturation effects, changes in dielectric constant) can be directly addressed. Various examples of practical value for functional ceramics and batteries are discussed. We believe that such discretization represents a substantial progress in the field of space charge theory being advantageous over introducing corrections into the already overstrained Gouy-Chapman function.
References

C. Xiao; C.-C. Chen; J. Maier, Discrete modeling of ionic space charge zones in solids, submitted.

C.-C. Chen, J. Maier, Decoupling electron and ion storage and the path from interfacial storage to artificial electrodes, Nature Energy
2018,
3 (2), 102-108.