bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Electrochemical Activity Assay of Non-Electroactive Enzymes
Authors: Gerulskis Rokas 
Published: November 2022

Enzymatic tools serve important functions in all areas of human life. Research aimed at comparing the catalytic rates of functionally overlapping enzymes of interest (EOIs) is hampered by expensive and time-consuming growth and purification procedures. Assaying the performance of already purified EOIs requires further laborious optimization. These assays are typically colorimetric and employ a downstream signal producing enzyme such as NADH-coupled dehydrogenases, which complicate assay optimization with their own unique chemical and pH requirements. Electrocatalysts such as 2,2,6,6-tetramethylpiperidine 1-Oxyl (TEMPO) have much broader pH ranges and substrate scopes (TEMPO oxidizing aldehydes and non-tertiary alcohols) than signal enzymes and output their catalytic rates directly as current density. The field of electrochemistry is also making strides in enzyme-electrode immobilization, with several works now reporting methods to anchor enzymes onto electrode surfaces directly from cell lysate, avoiding lengthy column-purification procedures.
This work proposes a hybrid electrolytic cell in which the catalytic rate of immobilized enzyme is quantified as current density produced by TEMPO-mediated oxidation of its products. The rate of production of carbon paper electrodes has been expedited and their functional area has been standardized through novel cutting and waxing procedures, demonstrating surface area coefficient of variation values up to an order of magnitude lower and production rates an order of magnitude higher than those of traditionally produced electrodes. Variation in electrode-loading of pyrene-anchored TEMPO has also been minimized, demonstrating current density variation identical to that of electrode functional area. Current work is investigating enzyme immobilization architectures employing electrode-immobilized DNA and Zinc-finger anchored enzyme to maximize enzyme loading, as well as enzyme-electrocatalyst reactivity to minimize background signal. In summary, we aim to develop an electrochemical assay of enzyme activity able to quantify the catalytic rates of a wide range of aldehyde and non-tertiary alcohol producing EOIs while minimizing the lengthy enzyme purification and assay optimization procedures of traditional colorimetric assays.
Mechanistic Insights into the Electrochemical Oxidation of Cyclohexane
Authors: Siboonruang Tana , Tang Maureen 
Published: November 2022

The detrimental effects of CO2 emissions from fossil fuels and the decreasing cost of electricity have accelerated interest in electrochemical synthesis. Electro-organic synthesis offers a sustainable and cost-effective pathway for chemical manufacturing. This method has the potential to minimize greenhouse gas emissions, enhance reaction selectivity, and replace hazardous chemical reagents with electric current.
Electrochemistry enables alternative mild temperature and pressure pathways to traditional thermochemical reactions. An intermediate step to producing nylon 6,6 is synthesis of KA oil, a mixture of cyclohexanone and cyclohexanol, from cyclohexane. This reaction is limited by low conversion and high pressures. An electrochemical approach can introduce a more selective reaction pathway at more benign conditions. Although electrochemical cyclohexane oxidation to KA oil has been demonstrated in literature, its mechanism remains poorly understood. In this work, we elucidate the mechanism of electrochemical cyclohexane oxidation. We report the oxygen source (water vs. oxygen) and the role of the counter electrode reaction cyclohexane oxidation. Through analysis of side products and electroanalytical methods, we suggest a reaction pathway. In addition, we use chronoamperometry to demonstrate that electrode material affects cyclohexane conversion and recommend the optimal catalyst for this reaction.
Me-N-C Electrocatalysts for Electrochemical CO2 Reduction to High-Value Products
Authors: He Yanghua , Weiss John Christian , Zelenay Piotr 
Published: November 2022

The development of sustainable carbon-neutral energy technologies to mitigate greenhouse gas emissions has become imperative and urgent. Of special interest and importance in this context is the use of electricity from intermittent renewable energy sources (wind, solar) for electrochemical conversion of carbon dioxide (CO2) to easily storable and transportable value-added products: fuels and feedstock chemicals. Nanoparticles of non-precious metals, e.g., Cu, Sn, Co, show high activity for electrochemical CO2 reduction reaction (CO2RR) but suffer from poor selectivity, resulting in a mixture of products that require tedious and costly separation. Recently, transition metal- and nitrogen-doped carbon (Me-N-C) materials have been emerged as promising CO2RR catalysts thanks to their well-defined structures and good activity. However, their selectivity, while respectable for the generation of carbon monoxide (CO), is low for high energy-content products. A limited understanding of reaction pathways and degradation mechanism of Me-N-C catalysts for CO2RR has additionally stemmed a rational design of these materials.
In this presentation, we summarize our study of the activity, selectivity, and stability of Me-N-C (Me = Fe, Co, Ni, or Cu, etc.) catalysts for the CO2RR, focusing on the role of the local coordination environment at metal centers and metal-carbon substrate interactions. We also report the obtained bimetallic M1M2-N-C catalysts, designed to enable the formation of multi-carbon products through CO2RR and utilizing high surface-area three-dimensional carbon matrix as support for metal sites with improved CO2RR activity. The main objective of this work is to use Me-N-C catalysts to produce high energy-density chemicals, enhance mechanistic understanding, and bring CO2RR closer to practical applications.
Influence of Fe Content in the Bifunctional Activity of LaFexCo1-XO3-δ Perovskite Catalysts for Zinc Air Batteries and Reversible Fuel Cells
Authors: Siddiqui Humera Khatoon , Waidha Aamir Iqbal , Kanbach Sabine , Kübler Markus , Palakkal Jasnamol Pezhumkattil , Haller Steffen , Clemens Oliver , Alff Lambert , Kramm Ulrike I. 
Published: November 2022

Eco-friendly energy-storage systems are needed to lower the fossil-fuel dependence and environmental contamination. Among energy storage technologies, metal air batteries offer a good and cheap perspective for the energy supply in small devices. However, its efficiency is low due to the slow kinetics of key reactions namely oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The same reactions occur in a reversible fuel cell. Perovskites have emerged as a promising candidate for alkaline condition due to the diversity in crystal structure, possibility of tuning electronic properties, low cost and earth abundance. Different catalytic descriptors for these ABO3-type systems are for instance eg orbital filling on B-site metals [1], high structural and chemical stability [2], oxygen vacancies [3], B-site metal oxygen covalency [4] and crystal structure [5]. Thus, a variation of the B-site is an effective strategy in order to enhance the catalytic properties [4][6].
In this work, LaFexCo1-xO3-
δ (x = 0 to 1) perovskites have been synthesized using a sol-gel approach and are characterized by several physicochemical techniques to identify the composition, structure and electronic state of iron and cobalt. We will discuss to what extent the activity depends on the descriptors as discussed above. Moreover, for our best performing material, its performance in Zn air battery was evaluated.
References:
[1] Suntivich, Y. S. Horn et al., Nat.
Chem.
3 (2011) 7, 546–550.
[2] Suntivich, Y. S. Horn et al., Science
334 (2011) 6061, 1383-1385.
[3] T. Mefford, K. J. Stevenson et al., Nat. Commun. 7 (2016) 11053.
[4] Duan, Z. J. Xu et al., Chem. Mater.
29 (2017) 24,10534–10541.
[5] Zhou and J. Sunarso, J. Phys. Chem. Lett. 4 (2013) 17, 2982–2988.
[6] Wang, Z. Feng et al., ACS Appl. Mater. Interfaces
11 (2019) 6, 5682-5686.

Figure 1
(Digital Presentation) Physicochemical Characterization of Sulfonate-Based Phosphonium Ionic Liquids
Authors: Tsunashima Katsuhiko , Hasegawa Shun , Okuno Yoshiharu , Yamada Hirohisa 
Published: November 2022

Ionic liquids (ILs) have unique physicochemical properties such as favorable solubility of organic and inorganic compounds, relatively high ionic conductivity, no measurable vapor pressure, high thermal stability, low flammability, etc. ILs are also promising liquid materials available for various applications because their function can be easily controlled by changing the combination of cations and anions and by introducing substituents. Although many kinds of ILs have already been investigated, phosphonium cation based ILs have rarely been proposed. We have previously designed and synthesized the phosphonium ILs together with typical sulfonylamide-based anions such as bis(trifluoromethylsulfonyl)amide and bis(fluorosulfonyl)amide anions.1,2) On the other hand, interests in phosphonium ILs consisting of the other anions is increasing for diverse applications. In this work, we design and prepare the ILs based on tetrabutylphosphonium cation (P4444
+) together with various sulfonate-based anions (Fig. 1), characterizing their physicochemical properties as a new family of ILs.
The phosphonium IL was prepared by an aqueous neutralization reaction of tetrabutylphosphonium hydroxide with the stoichiometric amounts of various sulfonic acids. The obtained phosphonium ILs were isolated by water evaporation, and were dried in vacuo for at least 1 day. The physicochemical properties of ILs, e.g. density, viscosity, conductivity (ac impedance method) and thermal decomposition temperature (thermogravimetric analysis), were measured under argon atmosphere.
The phosphonium salts based on unsubstituted sulfonate anions such as SO3CH3, SO3CH2CH3 and SO3(CH2)2CH3 were white crystalline solids at room temperature, whereas both amino- and hydroxy- substituted sulfonate salts were viscous liquids at room temperature. All phosphonium salts obtained were hydrophilic. Table 1 summarizes the physicochemical properties of phosphonium ILs based on amino- and hydroxy-substituted sulfonate anions. These phosphonium ILs exhibited considerably high viscosities when compared to the previously published viscosity value of P4444-lactate IL (415 mPa s at 25 °C)3), which suggests that the electrostatic interaction between P4444 cation and the sulfonate anions is much stronger than those in the case of carboxylate-based phosphonium ILs. It should be noted that P4444-SO3(CH2)3NH2 obviously indicated not only the highest density but also the highest viscosity and the lowest conductivity, which might be due to the fact that the IL has the largest anion to give a significant van der Waals interaction.

Figure 1
(Digital Presentation) Dielectric and Vibrational Spectroscopic Study on Asymmetric Quaternary Phosphonium-Based Ionic Liquids
Authors: Matsumoto Mitsuhiro , Kazuki Takeuchi , Inoue Yohtaro , Tsunashima Katsuhiko , Yamada Hirohisa 
Published: November 2022

Ionic liquids (IL) have a great potential of applications in electrochemical devices such as electrolytes for fuel cells. In particular, quaternary phosphonium cation-based ionic liquids (P-ILs) is much suitable due to lower viscosity and better ionic conductivity compared with corresponding quaternary ammonium cation-based ionic liquids (A-ILs). Over the past decade, fundamental properties of P-ILs have been investigated by viscometry, calorimetry, spectroscopy, calculation, and so on. However, little is known about molecular mechanism for such better potential of P-ILs. The present study aimed to reveal the relationship between molecular structure and macroscopic material properties of P-ILs in terms of alkyl chain asymmetry.
The P-ILs used in this study were prepared by quadrification of trialkylphosphine followed by ion exchange with bis(trifluoromethanesulfonyl)imide (TFSA) anions. We named P-ILs based on the number of alkyl chain length. For example, P2225 means triethyl(penta)phosphonium cation. In this study, we used P2225-TFSA, P2228-TFSA, and P222(12)-TFSA. We conducted temperature-variable broadband dielectric spectroscopy between 20 Hz and 100 MHz. We also carried out Raman spectroscopy (laser excitation at 532 nm) and THz spectroscopy.
The obtained complex dielectric spectra were dominated by (i) electrode polarization, (ii) ionic conduction, and (iii) reorientational relaxation, depending on the frequency and temperature. The spectra at the frequency regions between ionic conduction and reorientational relaxation were well-fitted with a Havriliak-Negami dielectric relaxation function, superimposed with a conductivity term. Thus, we determined both ionic conductivity (σdc) and relaxation time for structural relaxation (τHN) of ionic liquids. Although the σdc for all of the P-ILs used in this study exhibited similar Vogel-Fulcher-Tamman-type temperature dependence, the σdc slightly decreased with increasing the asymmetric alkyl chain length. Such temperature dependence was also observed in τHN, meaning that translational dynamics partly coupled with segmental dynamics. This result is consistent with that internal motion of the alkyl chains should depend on the chain length. Raman and THz spectroscopy provided an information on molecular structure (such as conformation) and inter- and intra-molecular interaction between anions and cations. In the presentation, we will describe the relationship of charge carrier transportation with ion conformations and intermolecular structures.
Deferred-Action Lithium-Based Batteries
Authors: Liu Danny , Garich Holly , Snyder Stephen , More Santosh R , Hall Timothy , Inman Maria , Taylor E. Jennings 
Published: November 2022

Deferred-action batteries, also known as reserve batteries, fulfill a unique role among energy storage technologies in which long-term shelf life (years, decades) is required while ensuring optimal performance upon activation. This objective is typically achieved through isolation of the electroactive components until battery operation is desired. Commonly, the electrolyte is isolated from one or both electrodes, and thus, limiting premature degradation and parasitic side-reactions until battery power is needed. During the reserve battery activation process, electrolyte is delivered to the electrode(s), which enable ionic conduction between the anode and cathode, and thus permitting normal operations analogous to a non-reserve design – which is ubiquitous among off-the-shelf batteries.
The feasible activation mechanisms are largely determined by battery chemistries and material properties, which give rise to several classifications including: thermal, spin-activated, and gas-activated reserve type batteries. Reserve battery activation under these various classifications require ancillary components and specific conditions which contribute excess complexity, weight, and volume towards the overall battery design and thus, significant penalties in reliability, specific and volumetric densities are incurred. Improvements in reserve battery technology must include strategies for limiting these penalties through innovated electrolyte delivery designs tailored for modern, high-energy, high-power density lithium-based batteries.
Herein, we report a novel electrolyte delivery mechanism facilitated by an electrochemical aperture. The electrochemical aperture serves as a physical barrier, isolating the liquid, lithium-containing electrolyte. Reserve battery activation proceeds via lithium transport, inducing physical transformations via the electrochemical aperture, which permit liquid electrolyte injection into the appropriate compartment(s). Accordingly, ionic conduction between the anode and cathode is established, and ultimately resulting in battery activation and enabling typical battery operation. Strategies for quantifying and reducing activation time via material optimization will be explored.
Acknowledgements: Faraday Technology acknowledges the technical assistance of Dr. Joseph P. Fellner at the Air Force Research Laboratory, Wright-Patterson AFB (Dayton, OH) under Air Force Contract No. FA8650-19-P2024 (Phase I SBIR) and FA8650-21-C-2300 (Phase II SBIR).

Figure 1
Key Aging Modes and Mechanisms for Extreme Fast Charging of Lithium-Ion Batteries
Authors: Tanim Tanvir R. , Yang Zhenzhen , Finegan Donal P. , Colclasure Andrew M. , Dufek Eric J. , Bloom Ira , Weddle Peter J , Evans Michael , Smith Kandler , Jansen Andrew N. 
Published: November 2022

Enabling extreme fast charging (XFC, charging in 10 to 15 minutes) in a lithium-ion battery (LiB) could play a key role in subsiding consumer’s range anxiety and spur the widespread adoption of electric vehicles (EVs).1,2 Such a high rate of charging induces unique aging modes in LiBs, thereby requiring a comprehensive understanding to enable effective solution strategies to minimize the negative effects of life and performance. This presentation will present a comprehensive understanding of the dominating aging modes and mechanisms of XFC in low- and moderate-loading Gr/NMC LiBs.
We will discuss the major limitations of XFC in LiBs by first using experimental and modeling results followed by a comprehensive electrochemical analysis of cycle life aging implications for different charging conditions (e.g., 1C to 9C rate conditions). We will then discuss the aging mechanisms using comprehensive post-testing as well as multimodal and multi-scale microscopy techniques.
Solid state diffusion in the negative electrode is not a key limiting factor for the fast charge conditions evaluated. Inadequate Li+ transport through the electrolyte primarily causes performance and distinct aging phenomena in LiBs. Eliminating the Li+ transport limitation within the electrolyte can offer a distinct increase in material utilization, avoiding Li deposition. Under such circumstances, the cathode could degrade in distinct ways depending on the particular NMC (e.g., NMC532 vs. NMC811) variants.
NMC811 experiences a greater subsurface crystallographic degradation and interfacial degradation and displays similar extents of sub-particle cracking as compared to NMC532 under comparable charging conditions. Surprisingly, the NMC811 maintains superior electrochemical performance despite the more aggressive degradations. We found the better cycle life performance of NMC811 to be related to its inherently better solid state diffusion, electronic conduction, and radially oriented grain architecture.

References

S. Ahmed et al., J. Power Sources, 367, 250–262 (2017).

Y. Liu, Y. Zhu, and Y. Cui, Nat. Energy, 4, 540–550 (2019).
(Invited) In Situ Electrochemical Raman Spectroscopy for Nanoscale to Macroscale Electrochemical Processes
Authors: Ren Bin 
Published: November 2022

Raman spectroscopy has been increasingly applied in studying the electrochemical processes, including adsorption and reaction, under in situ or operando condition, because Raman spectroscopy can conveniently work in aqueous solution and provide fingerprint molecular information. In this talk, I will present the recent work in my group on developing various electrochemical Raman spectroscopy for in-situ and operando studies of electrochemical systems at the limits of time and spatial resolution and sensitivity
With the help of the plasmonic enhancement at the tip of a plasmonic material, electrochemical tip-enhanced Raman spectroscopy (EC-TERS) offers itself as the only nanospectroscopy for investigating the electrochemical interface with unprecedent spatial resolution and explicit chemical fingerprint information. We developed the electrochemical TERS both based on STM and AFM using the water immersion objective and homemade optical instrument. EC-TERS was applied to obtain the molecular fingerprint information of surface adsorption and electrochemical reaction on single crystal surfaces and monitor the plasmon-driven reaction at the nanoscale.
Aiming at addressing the challenge of monitoring the highly dynamic changing electrochemical interfaces under potential control and presence of the electrolyte, a transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) was developed to monitor the structural evolution of surface species at a time resolution that equals the transient electrochemical methods (e.g. cyclic voltammetry and chronoamperometry), allowing the precise correlation of Raman signal with the molecular signature information and the electrochemical current signal. He observed an interesting two-step reaction processes that are impossible to observe by conventional steady state SERS methods. A wide-field Raman imaging system was developed to offer a high imaging speed to monitor the spatial and temporal change at every point over the whole electrode surface simultaneously. The heterogeneity of electrocatalytic reaction on the electrode surface was observed. This technique offers the possibility to spatially correlate electrochemical behavior and the particular surface sites where the reaction happens.
Oxidation of Aqueous H3PO3 on Pt Studied By X-Ray Spectroscopies
Authors: Wibowo Enggar , Garcia-Diez Raul , Bystron Tomas , Prokop Martin , van der Merwe Marianne , Arce Mauricio D. , Jiménez Catalina Elena , Efimenko Anna , Favaro Marco , Starr David , Gaupp Andreas , Wilks Regan George , Bouzek Karel , Bär Marcus 
Published: November 2022

High-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) employing a phosphoric acid H3PO4-doped membrane are considered to be promising sustainable electrochemical energy storage. The high-temperature operation has several advantages, such as a higher tolerance to CO poisoning, allowing coupling of HT-PEMFCs with reformers [1-3], as well the possibility for heat and electric energy co-generation [1,2]. However, during operation, phosphorus oxo-acids (e.g.: H3PO3) are generated on the anode. These impurities adsorb on the Pt catalyst [4-6], thus possibly negatively affecting the HT-PEMFCs performance. A detailed understanding of the H3PO3-catalyst (Pt) interaction is hence necessary for further HT-PEMFC optimization. However, besides an investigation of the H3PO3 adsorption behavior on Pt [6,7], literature on the behavior of the H3PO3 in contact with Pt (with/without polarization) is scarce.
In this work, the oxidation mechanism of H3PO3 was investigated using a combination of in situ x-ray spectroscopy techniques that directly probe the H3PO3/Pt interface interaction, complemented by ex situ x-ray photoelectron spectroscopy (XPS) and ion-exchange chromatography (IEC). IEC gave insights into the effect of Pt on the stability of deaerated aqueous H3PO3 solutions. XPS was conducted on H3PO3/support structures (including Au and Pt supports) to determine to what extent the support affects the H3PO3 oxidation. Furthermore, in-situ dip and pull near-ambient pressure (NAP-)XPS was conducted to investigate the state of H3PO3 at the H3PO3/Pt interface and in solution bulk. It was observed that at the H3PO3/Pt interface, H3PO3 was chemically oxidized to H3PO4, while in the bulk solution it remains stable, as shown in Figure 1. Moreover, in situ x-ray absorption spectroscopy at the P K-edge was conducted at different concentrations of H3PO3 in aqueous solutions (i.e., different amounts of H2O) in contact with Pt, to determine the role of H2O in the oxidation of H3PO3. A higher degree of oxidation was observed for the less concentrated H3PO3, implying that H2O participates in the oxidation mechanism of H3PO3 to H3PO4.
References:
[1] Chandan et al., A.. J. Power Sources 2013, 231, 264–278. [2] Asensio, et al. Chem. Soc. Rev. 2010, 39 (8), 3210. [3] Q. Li et al, J. Electrochem. Soc. 2003, 150 (12), A1599. [4] Sugishima et al, J. Electrochem. Soc. 1994, 141 (12), 3332. [5] Doh et al. ChemElectroChem. 2014, 1 (1), 180–186. [6] Prokop et al, Electrochimica Acta 2015, 160, 214–218. [7] Prokop et al, Electrochimica Acta 2016, 212, 465–472.

Figure 1