bluuebunny/crossref_metadata_2025 huggingface dataset:
(Digital Presentation) Biocatalytic Synthesis of Chiral Compounds in Microemulsions Using Electrode-Driven Enzyme Activation
Authors: Thiruwana Kankanamage Rumasha , Hena Jr John , He Jie , Rusling James
Published: July 2022

Biocatalysis in bicontinuous microemulsions is a promising approach for synthetic routes to regio- and stereoselective and efficient synthetic processes. Redox enzymes such as peroxidases and monooxygenases can be attached to surfaces for biocatalysis and operated in low toxicity microemulsions to enhance the dissolution of non-polar reactants, but still provide a water rich environment for the enzyme catalysis resulting in high product yield and chiral products. Here we report a new hybrid electrocatalyst system for biocatalysis using a synthetic Cu-polymer catalyst deposited on an electrode and cross-linked films of poly(L-lysine) (PLL) and redox enzymes horseradish peroxidase (HRP) and cytochrome P450 (Cyt P450) in films on oxidized pyrolytic graphite (PG) electrodes or carboxylate functionalized magnetic particles. Enzymes in these catalytic films are activated by O2 conversion to H2O2 by the Cu polymer. In microemulsions, enzyme reactions occur in a water-rich film environment with delivery of non-polar reactants from the oil-rich regions of the microemulsion. Reactions can be achieved that cannot be run in water due to lack of reactants solubility. Rotating-disk voltammetry (RDV) was used to assess catalytic activity of cross-linked enzyme/PLL films in the presence of H2O2. Activity of cross-linked HRP on magnetic particles was similar to that of 3 mg/mL of free HRP, and these HRP-beads can be used for synthesis up to 95 °C. Oxidation of 2-naphthol by HRP/PLL coated magnetic particles in microemulsions resulted in (R)- and (S)-1,1’-Bi-2-naphthol with chiral ratio determined by chiral HPLC. High product yields of oxidation products were achieved at 80 °C than 20 °C, with product analysis suggesting increasing catalytic efficiency and selectivity at higher temperatures. Additional chiral HRP reactions will be described, and cross-linked Cytochrome P450s are also being explored for stereoselective oxidation and hydroxylation of substrates including styrene, ethyl benzene and 1-tetralone.
Sensing and Characterization of Agricultural Mycotoxins Using Electrochemistry
Authors: Lima Dhésmon , Arteshi Kojabad Yaser , Mendes Hacke Ana Carolina , Kuss Sabine
Published: July 2022

Mycotoxins are highly toxic and can be found as contaminants in products derived from cereals and grains.1 According to the Canadian Food Inspection Agency (CFIA), at least 25% of the grain produced each year worldwide present mycotoxin contamination.2 Among the mycotoxins of major concern in Canada is ochratoxin A (OTA),2 which is produced mainly by Aspergillus fungi species.3 Because of its severely negative health effects, the detection of this compound in grain and food samples is highly relevant and regulated by the legislation.2 OTA has been detected in food products and commodities through costly and time-consuming methods, such as chromatography.4 Existing electrochemical sensors are still based on systems that are too complex and expensive for industrial applications.5,6 Herein, we propose a rapid, reliable and cost-efficient sensing strategy for OTA detection, which is based on glassy carbon electrodes (GCE) modified with PtNPs.7 OTA is characterized for oxidation and reduction potentials, diffusion behaviour, and limits of detection and quantification. To this end, we aim to develop a practical and highly sensitive electroanalytical methodology that will enable us to detect OTA in grain samples in the future.

References

B. Scafuri et al., Scientific Reports, 7, 1–11 (2017).

L. L. Charmley and H. L. Trenholm, RG-8 Regulatory Guidance: Contaminants in Feed (2017) https://inspection.canada.ca/animal-health/livestock-feeds/regulatory-guidance/rg-8/eng/1347383943203/1347384015909?chap=1.

T. R. Bui-Klimke and F. Wu, Critical Reviews in Food Science and Nutrition, 55, 1860–1869 (2015).

R. Chauhan, J. Singh, T. Sachdev, T. Basu, and B. D. Malhotra, Biosensors and Bioelectronics, 81, 532–545 (2016).

A. Suea-Ngam, P. D. Howes, C. E. Stanley, and A. J. Demello, ACS Sensors, 4, 1560–1568 (2019).

K. Kunene et al., Sensors and Actuators, B: Chemical, 305 (2020).

E. Mazzotta et al., ACS Applied Nano Materials, 4, 7650–7662 (2021).
Liquid-Liquid Phase Separation Effects on Electron Transfer Kinetics and Thermodynamics
Authors: Wang Stephanie , Davis Connor , Sepunaru Lior
Published: July 2022

Water-in-water droplets formed by liquid-liquid phase separations are a method of membraneless cellular compartmentalization, allowing a cell to quickly organize enzymes to respond to events without the high energy expenditure associated with forming membraned compartments. This organization drives increased catalytic rates of enzyme reactions. Though some of this surge can be attributed to localization and condensation of substrate and enzyme, it cannot account for the total increase. We hypothesize that the inner environ of a LLPS droplet provides a unique solvation environment compared to the bulk phase and should thus alter the thermodynamics of reactions within it. Using an extension of Marcus theory, we describe these effects which are observed in a shifted formal potential. Here, we demonstrate this proof of concept, employing fluorescent dyes as redox reporters: single-entity electrochemistry is used to quantify probes partitioned into LLPS droplets. These findings should aid biophysical explorations of these membraneless organelles of emerging interest and importance.

Figure 1
Electrochemical Characterization of Auranofin in Aqueous Media
Authors: Yosseif Melak , Singh Vikram , Maydaniuk Dustin , Cardona Silvia , Kuss Sabine
Published: July 2022

Detection of antibiotic compounds in various media is necessary in solving the public health crisis of antibiotic resistance[1]. Auranofin (AF) is a repurposed antibiotic first used as an antirheumatic in the 1950s. It is useful against various bacteria, fungi, virus infections and cancers either by itself or synergistically with other antibiotics[2–5]. AF is composed of aurothioglucose and phosphine moieties, and therefore, has lipophilic and hydrophilic properties, making its characterization in aqueous media particularly difficult. In the presented study, electrochemistry was employed to characterize and detect AF in aqueous solutions using modified glassy carbon electrodes (GCEs), coated with Carbon Black (CB). CB coating was optimized, oxidation and reduction potentials were identified, and pH dependence, as well as Limits of Detection (LOD) and Quantification (LOQ) were determined. Interferences with ions and other antibiotics was studies and are important factors for the detection of AF in the environment. This study reports on the sensitivity, stability, and selectivity of the CB-GCE sensors, proving useful for future field detection and/or bioelectrochemical investigations.

CITATIONS

[1] M.R. Islam, S. Kuss, F. Schweizer, Characterization of Antibiotic Compounds By Electrochemistry, ECS Meeting Abstracts. MA2020-01 (2020). https://doi.org/10.1149/ma2020-01442531mtgabs.

[2] R. Díez-Martínez, E. García-Fernández, M. Manzano, Á. Martínez, M. Domenech, M. Vallet-Regí, P. García, Auranofin-loaded nanoparticles as a new therapeutic tool to fight streptococcal infections, Scientific Reports. 6 (2016). https://doi.org/10.1038/srep19525.

[3] K.J. Habermann, L. Grünewald, S. van Wijk, S. Fulda, Targeting redox homeostasis in rhabdomyosarcoma cells: GSH-depleting agents enhance auranofin-induced cell death, Cell Death & Disease. 8 (2017). https://doi.org/10.1038/cddis.2017.412.

[4] E. v. Capparelli, R. Bricker-Ford, M.J. Rogers, J.H. McKerrow, S.L. Reed, Phase I clinical trial results of auranofin, a novel antiparasitic agent, Antimicrobial Agents and Chemotherapy. 61 (2017). https://doi.org/10.1128/AAC.01947-16.

[5] T. Onodera, I. Momose, M. Kawada, Potential anticancer activity of auranofin, Chemical and Pharmaceutical Bulletin. 67 (2019). https://doi.org/10.1248/cpb.c18-00767.
(Digital Presentation) Water Treatment through the Arc and Pulsed Spark Discharge
Authors: Amini Maryam , Rasouli Milad , Ghoranneviss Mahmood , Ostrikov Kostya (Ken)
Published: July 2022

Water deterioration and depletion are accompanied by population growth and fast urbanization, posing major environmental problems. The prevalence of water-borne infections remains high, making it critical to discover effective ways of disinfecting water thoroughly. The main methods for inactivating a wide spectrum of harmful bacteria are chemical, physical, electrochemical, and radical. Conventional decontamination methods not only fail to completely disinfect water but also have several drawbacks, including the generation of disinfection byproducts; the complexity of disinfection reactor design; high energy consumption; and high running expenses. As a result, a versatile approach should be developed to overcome the limitations of current decontamination methods while also being efficient against a variety of diseases. Plasma-based water treatment has recently emerged as a possible alternative to traditional approaches. Plasma has proven to be more effective than conventional oxidants and disinfectants, both directly and indirectly. Plasma-related effects vary depending on the type of discharge, device settings, and process parameters. Electrical discharges are one of the most effective water treatment treatments. To this end, two plasma discharges, i.e., arc and pulsed spark discharge, are used for the treatment of synthetic contaminated water with microorganisms, which can be used for naturally contaminated surface water. Our results revealed that in comparison to arc discharge, pulse spark discharge produces more extreme acidic conditions by lowering the pH of water samples as well as a more reactive environment, which results in greater antibacterial efficacy. Furthermore, water samples treated with arc discharge had greater temperatures than water samples treated with pulse spark discharge, indicating that temperature was not a critical effector in the plasma-based sterilizing process.
2D Ultrathin NiCo2S4 Nanosheets-Assisted 3D Highly Stable Lithium Metal Anode
Authors: Zhang Xuzi , Li Ge
Published: July 2022

Lithium (Li) metal is usually considered one of the most promising anode candidates for next-generation batteries owing to its extremely high specific capacity and low reduction potential. However, the application of Li metal anode is still hindered by the uncontrolled growth of dendritic Li and extreme volume fluctuation during cycles. Herein, we demonstrate a flexible and self-supporting 3D interlaced carbon nanofibers coated with 2D ultrathin NiCo2S4 nanosheets (denoted as CNF@NiCo2S4) which are containing high lithiophilicity and porous structure. This unique structure can significantly reduce the exchange current density and improve the performance for plating Li. Moreover, metallic Li can be further confined within the interspace among the CNF and inside the porous carbon nanoboxes significantly avoiding dendritic Li formation. The CNF@NiCo2S4 composite anode exhibits a long-running lifespan for 1000h with an exceptionally low voltage hysteresis. Full cells with LiFePO4 cathode and LiǀCNF@NiCo2S4 anode show typical voltage profiles but enhanced cycle performance than that of LiFePO4 coupling with bare Li anode at low N/P ratio.
Graphitizable Phenolic Networks As a Tailored Soft Carbon Platform for Silicon-Based Anodes of Lithium Ion Batteries
Authors: Nam Myeonggyun , Yoo Pil Jin
Published: July 2022

Tannic acid (TA) has the magnificent potentials for various electrochemical applications due to their facile coating property and the chelating ability with any metallic species. However, since the ester group present in TA is thermally decomposable, TA is prone to full thermal degradation upon the carbonization process, rarely remaining a residual carbon for further electrochemical reactions. Furthermore, the type of residual carbons is a hard carbon, which is unfavorable for the high coulombic efficiency due to their high surface area and the structural defects. To overcome this limitation and improve the carbonizability of TA, we employed a modularization strategy through rearranging the molecular structure of TA. During this rearrangement process, TA molecules simultaneously undergo C-C coupling and esterification at each aromatic unit with remarkably enhanced molecular cyclicity to generate modularly interconnected TA (m-TA). The carbonized m-TA provides high residual carbon content, indicating the soft carbon behavior (42% @ 900℃). Furthermore, after the incorporation of metallic species to form modularly interconnected metal-phenolic networks (m-MPN), the graphitic sp2 domains hybridized with metalized nanoclusters present in m-MPN synergistically imparted outstanding ionic and electrical conductivities in the carbonized m-MPN after pyrolysis. The ideally created new electrochemical platform of the carbonized m-MPN was utilized as a supportive layer of silicon nanoparticles (Si@C/metal). Especially, various types of metals (Ni, Fe and Sn) were introduced to the carbon layers indicating diverse functions for the electrochemical performance, establishing a highly stable and active anode for lithium ion battery systems.
(Invited) Oil-Immersed Scanning Micropipette Contact Method for Long-Term Corrosion Mapping
Authors: Li Yuanjiao , Mauzeroll Janine
Published: July 2022

Scanning micropipette contact method (SMCM) suffers from the droplet evaporation and crystallization which limits the use of most saline electrolyte solutions under natural air humidity. We advanced this technique by scanning the droplet under mineral oil that was placed on the surface of substrate, which significantly improved the stability of droplet. This allowed for the use of 3.5 wt% NaCl solution to map the localized corrosion of AA7075-T73 aluminum alloy regardless of ambient humidity levels. Maps of corrosion potentials and corrosion currents extracted from potentiodynamic polarization curves showed good correlations with the surface features. We also optimized the long-term oil-immersed SMCM scanning by eliminating the Ag+ contamination that was released by the commonly used non-isolated Ag/AgCl quasi-reference counter electrode (QRCE). Ag+ ions were reduced at the alloy surface when they diffused to the droplet, generating unwanted cathodic current, causing the corrosion potential to shift in the positive direction over time. This work demonstrates the viability of the oil-immersed SMCM and opens up the avenue to mechanistic corrosion investigations at the microscale level using aqueous solutions that are prone to evaporation under noncontrolled humidity levels.
Efficient BiVO4 Photoanode Fabricated Via Sputtering on Patterned Fto
Authors: Ju Sucheol , Kim Nak Hyun , Park Jaemin , Lee Heon
Published: July 2022

Bismuth vanadate (BiVO4) is a promising photoanode material; however, its efficiency significantly changes depending on the atomic ratio of Bi/V, and there is no suitable method for synthesizing large-area photoanodes. In this study, an efficient BiVO4 photoanode was fabricated via sputtering, by manipulating the molar ratio of Bi/V with V solution annealing. V solution annealing not only adjusted the atomic ratio of Bi/V but also increased the number of O vacancies, thereby improving the charge-separation and charge-transport efficiencies. Consequently, the photocurrent density of the sputtered photoanode with V solution annealing (BVO-V) was 1.86 mA/cm2, which is 23 times higher than that of the sputtered photoanode annealed under air conditions (BVO-A, 81.0 µA/cm2). Furthermore, microcone-patterned fluorine-doped SnO2 was fabricated to increase the active area and reduce the high reflectance, owing to the dense deposition because of the sputtering. Thus, the photocurrent density of the MC-BVO was 3.11 mA/cm2, which is approximately 67% higher than that of BVO-V (1.86 mA/cm2).

Figure 1
3D-Branched Fe2O3 Nanorods on Micropillar Arrays Decorated with Co-Pi for Enhanced PEC Water Splitting
Authors: Kim Nak Hyun , Ju Sucheol , Park Jaemin
Published: July 2022

Photoelectrochemical(PEC) water splitting has gained great attention as a route for future hydrogen production owing to its sustainable and cost-effective properties. However, since PEC water splitting has limitations on efficiency and stability, research on materials, structures and catalysts are in progress to solve those problems. In our experiments, the nano-pattern structure is created using direct-printing to increase the photoanode efficiency.

In this study, enlarged surface area is accomplished by micropillar structured FTO and Fe2O3 nanorods. We fabricated micropillar structure via direct printing method. The direct-printing method has advantages in not only simple process but also low price to form micro-nano size structures. To obtain micropillar structure, spin coating of hydrogen silsesquioxane(HSQ) was performed on micropillar patterned polydimethylsiloxane(PDMS) mold. Then, we applied glass substrate and pressure on it. Detachment of PDMS mold is followed by deposition of FTO layer. Hydrothermally synthesized Fe2O3 nanorods are formed on micropillar structured FTO and Co-Pi catalyst was electrodeposited on Fe2O3 nanorods to enhance surface water oxidation.

Due to micropillar pattern, optical absorption of patterned Fe2O3 photoanode is higher than that of flat Fe2O3 photoanode in the whole range of optical wavelength. Also micropillar patterned Fe2O3 sample showed 2.6 times higher photocurrent at 1.23 VRHE than flat Fe2O3 sample. These results were confirmed that micropillar structure increased the surface area and light scattering effect. Furthermore, applying Co-Pi catalyst increased photocurrent at 1.23 VRHE for 2.0 times higher owing to the enhancement of surface water oxidation. As a result, photocurrent of the micropillar patterned, decorated with Co-Pi sample shows 1.51 mA/cm2, and that of flat, non-decorated sample shows 0.29 mA/cm2 at 1.23 VRHE.

Figure 1
Towards Quantitative Interpretation of Normal Incidence Differential Reflectance (NIDR) Measurements for Electrochemical Dynamics Experiments
Authors: Strobl Jonathan R. , Borisov Anatole , Scherson Daniel
Published: July 2022

Normal incidence differential reflectance, or NIDR, is an in-situ technique suitable for high time resolution monitoring of the interfacial structure and composition of electrode-solution interfaces. Recent efforts have been focused in our laboratory on formulating quantitative models for interpreting the potential-, and coverage-dependence of NIDR signals for use in monitoring interfacial dynamics at Au electrodes in various electrolytes. A simple model capturing the aforementioned dependences will be presented. Within the framework of this model, different limiting behaviors are anticipated depending on the optical properties of the adsorbate and the nature of its interactions with the Au surface. In addition, some exemplary data sets on Au electrodes will be discussed, namely cyclic voltammetry and potential steps on single crystals and polycrystalline Au surfaces in aqueous perchloric acid solutions. The NIDR responses to these potential perturbations can be rationalized on the basis of the optical properties of perchlorate and its interaction with the surface. All NIDR data are consistent with adsorbed perchlorate exhibiting optical properties that deviate minimally from that of water, as well as perchlorate physisorbing on Au rather than chemisorbing. In essence, the NIDR signal is proportional to the charge stored on the Au surface, with no change in said proportionality with perchlorate adsorption, rendering this adsorbate essentially ‘invisible’ to NIDR. This has obvious implications when using perchlorate salts as a supporting electrolyte in NIDR experiments, as perchlorate will produce no NIDR response and therefore will not convolute with the NIDR response arising from other adsorbates. To demonstrate this in practice, NIDR experiments for Se covered Au electrodes in aqueous perchloric acid electrolytes will be discussed and the clear dependence of the NIDR response on Se coverage will be demonstrated.
GPS for the SEI: Charting Electrochemical Mechanisms with Reaction Networks
Authors: Spotte-Smith Evan Walter Clark , Blau Samuel M , Persson Kristin A.
Published: July 2022

An electrolyte is placed under an applied potential - what happens next? This question of electrochemical reactivity seems simple on its surface. However, the answer of what intermediates, products, and byproducts will form, as well as how they will form, is immensely challenging to predict. Traditional theoretical methods have either used intuitively guided mechanistic calculations (e.g. density functional theory) that abstract away competition between reactions or dynamical simulations (e.g. ab initio molecular dynamics) that are computationally intractable beyond extremely short time scales. Recently, we have taken a new approach: using data-driven reaction networks to automatically explore electrochemical reactive landscapes. In this talk, we will present an end-to-end methodology to answer questions of reactivity in complex environments. Drawing from recent studies of solid electrolyte interphase (SEI) formation in lithium-ion batteries, we will describe how to generate and analyze reaction networks, leading to insights regarding both formation mechanisms of experimentally identified products as well as the prediction of novel SEI components. We will then illustrate how individual mechanisms obtained via reaction networks can be combined to understand reactive competition using kinetic Monte Carlo simulations. The methodology that we describe has potential not just to expand our understanding of battery chemistry, but of electrochemical reactivity in general.
Screen-printed Electrodes with Stable Solid-state Reference Electrode for Oxidation-reduction Potential (ORP) Measurement Applications
Authors: Williams Kia , González-García María Begoña
Published: July 2022

ORP is defined as the electromotive force between a noble metal electrode and a reference electrode when immersed in solution [1]. The electrochemical setup typically involves a platinum wire as a working electrode (sometimes gold, rarely silver) and a well-controlled reference electrode. When these electrodes are immersed together into a solution, an electron migration is produced between the working electrode and the solution. Depending on the nature of the species diluted, the working electrode loses electrons if the media is an oxidant, so the potential measured becomes positive. If the media is reductive, the working electrode gains electrons, and the resulting potential will be negative. Voltage is measured between both electrodes (working and reference electrode), so the ORP value is usually given in millivolts.

ORP provides valuable information because it is a measure of sanitizer activity and water quality, due to the changes in ORP being associated with the existence of contaminants or biological activity. ORP measurements are also useful in several major industrial applications where maintaining potential in a production stage under control is a critical parameter or when it is necessary to assure the quality of water. Examples include cyanide oxidation or chrome reduction in wastewater treatment of metal-plating industry residues, bleach production and bleaching of paper, biological growth control in cooling towers and water quality monitoring in swimming pools, hot tubs, spas, or aquafarming.

Screen-printed electrodes (SPEs) offer several interesting advantages in industrial applications such as point-of-care testing, usability, and a wide range of possible customizable setups. However, most SPEs include a pseudo-reference electrode fabricated with silver or silver/silver chloride. Since the KCl electrolyte is absent, this pseudo-reference electrode is exposed to media implying that the reference electrode is not under control, especially in aggressive media. In this publication, an SPE with a platinum paste working electrode and a controlled solid-state reference electrode is presented. Several experiments are included to show that these platforms offer ORP monitoring in household, industrial or laboratory applications.

References:

[1] ASTM D1498 - 14 - Standard Test Method for Oxidation-Reduction Potential of Water
Carbon-Capped Monometallic and Bimetallic Catalysts for Hydrogen Oxidation Reaction (HOR) and Their Positive Features on Durability in Alkaline Conditions
Authors: Sgarbi Ricardo , Doan Huong , Chatenet Marian
Published: July 2022

Alkaline fuel cells (AFC) and anion exchange membrane fuel cells (AEMFC) have exhibited attractive advantages versus their acid counterparts, including the strategical possibility of using PGM-free catalysts in the electrode composition.[1,2] PGM-free catalysts remain a challenge regarding the hydrogen oxidation reaction (HOR) catalysis, due to the reduced initial and long-term performance so far.[3,4] PGM-based materials have the highest HOR performances,[5] but Pt- and Pd-based catalysts undergo detrimental metallic nanoparticles detachment from the carbon support and agglomeration (in minor extent) upon extended potential cycling in the alkaline environments.[6,7] In this work, we explore the effect of long-term durability on the nanoparticles wrapped by a carbon layer, labeled here as capped catalysts; two different types of carbon-capped catalysts are evaluated, such as monometallic (PdG2/C) and bimetallic (PdNiG2/C) against their commercial ones (Pd/C and PdNi/C from Premetek). All the catalysts were evaluated in RDE set-up, in couple with IL-TEM, XPS and ICP-MS techniques for before and after accelerated stress test (0.1 – 1.23 V vs. RHE – 3s each potential), up to 6000 cycles. The durability enhancement is achieved when: i) there is a carbon-cap and ii) there is a second metal (i.e. Ni) on the surface of Pd. Thus, in the case of carbon-capped bimetallic (PdNiG2/C), there is a double protection of the Pd nanoparticles (from the carbon-cap and the presence of nickel). In the same time, the HOR activity is high. In the end, the best compromise of durability follows the trend: PdNiG2/C > PdNi/C > PdG2/C > Pd/C. These positive features of the carbon-capped bimetallic material open the way to the design of robust catalysts for highly-durable anodes for alkaline fuel cell systems.

[1] D. R. Dekel, J. Power Sources
2018, 375, 158–169.

[2] E. Wagner, H. ‐J. Kohnke, Fuel Cells
2020, 1–12.

[3] A. G. Oshchepkov, G. Braesch, A. Bonnefont, E. R. Savinova, M. Chatenet, ACS Catal.
2020, 10, 7043–7068.

[4] W. E. Mustain, M. Chatenet, M. Page, Y. S. Kim, Energy Environ. Sci.
2020, 13, 2805–2838.

[5] W. Sheng, M. Myint, J. G. Chen, Y. Yan, Energy Environ. Sci.
2013, 6, 1509–1512.

[6] C. Lafforgue, F. Maillard, V. Martin, L. Dubau, M. Chatenet, ACS Catal.
2019, 9, 5613–5622.

[7] A. Zadick, L. Dubau, N. Sergent, G. Berthomé, M. Chatenet, ACS Catal.
2015, 5, 4819–4824.
(Digital Presentation) Deconvoluting and Quantifying Real-Time Fluxes and Ionic Currents of Various Species Using in Situ Electrochemical Quartz Crystal Microbalance Measurements
Authors: Lin Zifeng , Zheng Kai , Xian Yongqiu
Published: July 2022

Electrochemical quartz crystal microbalance (EQCM) is a powerful technique to screen the gravimetric response of electrochemical electrodes. In this study, a straightforward mathematical method is proposed for extracting and deconvoluting the real-time fluxes and ionic currents of two species based on the EQCM measurement results. We creatively propose the concept of Flux cyclic voltammograms (CVs) and ionic current CVs of various species and apply them to the real-time analyses of molecules/ions dynamics. For proof of concept, Ti3C2T
x
MXene, a most studied two-dimensional metal carbide, is investigated as a supercapacitor electrode in a 1M H2SO4 electrolyte. The H2O and H+ flux CV plots are highly symmetrical, indicating reversible inserting/deserting species fluxes. The highest fluxes along with maximum hydration numbers are obtained at the peak current potential. This suggests the significant contribution of double-layer capacitance originates from the insertion of hydrated H+. The H+ CV with the ionic current induced by H+ flux overlaps the real CV, confirming that H+ is the only interactive ion for screening the electrode charge. Lastly, we also validate the proposed strategy using Ti3C2T
x
MXene electrode in 1M KCl electrolyte and YP80 porous carbon electrode in 1 M LiCl electrolyte.
(Digital Presentation) Uncertainty Analysis on Activity Coefficients Determination Using Vapor Pressure Osmometry on Electrolyte Solutions
Authors: Aguilar-Arias Jaime , Carvajal Perdomo Sergio Andres , Gutiérrez Cristian
Published: July 2022

Vapor Pressure Osmometry (VPO) is a reliable technique for experimental measurement of both activity coefficient of solvents and molar weight of solutes. In this work were analyzed the uncertainty sources that affect the measurements on VPO, establishing a general model for uncertainty, and applying this model to the particular case of a VPO prototype designed and constructed in this work as well. In the analysis was included the effect of strong electrolyte solutes of different ratios on the uncertainty of the measurements.

In order to obtain a reliable mathematical model, a simplified thermodynamic model for the activity coefficient was used. Two types of electrolytes (1:1 and 1:2) were used for experimental runs in the diluted and non-diluted concentrations.

The osmometer was designed using thermistors, so, four commercial thermistors of two different types were calibrated in the range of 0-40°C according to ASTM E879 Standard, obtaining an expanded uncertainty of 0.014°C with a confidence level of 95%.

For the uncertainty budget, the relevant sources were identified and quantified. The expected uncertainty of the measurements ranged from 1.03x10-6 to 1.81x10-4 for the estimation of the activity coefficient with a confidence level of 95%.
Nonlinear Behavior during the Electrochemical Oxidation of Thiols
Authors: Glasco Dalton Lee , Bell Jeffrey Gordon
Published: July 2022

The electrochemical behavior of sulfur-containing compounds is of great importance in fields ranging from diagnostics to energy-storage and materials chemistry. For example, thiols (R-SH) are important components of many electrochemical sensors and are routinely used in materials applications as they are known to form well-ordered and reproducible monolayers (self-assembled monolayers, SAMs) on various metal surfaces. Sulfur compounds are also interesting from the viewpoint of nonlinear dynamics owing to the presence of multiple oxidation states, which has been exploited to study complex dynamic behavior in both chemical and electrochemical systems. In this work we explore the oscillatory behavior of 2-(dimethylamino)ethanethiol (DMAET), a known hydrolysis product of V-type nerve agents, on platinum electrodes. Interestingly, the electrochemical oxidation of DMAET leads to two distinct regions of oscillatory behavior. Probing the system with electrochemical impedance spectroscopy (EIS), resulted in the classification of the DMAET system as an HN-NDR type oscillator. These results are compared to structurally similar thiol containing compounds towards the goal of elucidating general features which permit the evolution of dynamic behavior in thiol-based electrochemical systems.
The Cation Role in Ion Transport Selectivity of Gold-Plated Nanotubes
Authors: Bush Stevie N , Martin Charles R
Published: July 2022

Ion permselectivity is an important ionic transport property exhibited in nanopores and nanotubes. Permselectivity develops due to the strong interactions between ions in solution and the nanopore/nanotube surfaces. Here, we study the ion permselectivity of gold-plated nanotube membranes. Gold-plated membranes were obtained by using an electroless gold plating method to deposit gold nanotubes into the pores and on the faces of track-etched polycarbonate membranes. These membranes have the potential to display cation permselectivity due to the excess surface charge density present on the membrane from chemisorbed Cl- anions. The cation permselectivity of membranes with 9.9 + 0.6 nm diameter nanotubes was studied potentiometrically by using a concentration cell. A new Debye-sphere based model was presented here to describe the extent of permselectivity. However, some ion specific effects with the gold-plated membrane are observed that cannot be interpreted by Debye theory. These ion-specific surface interactions lead to a reduction in the negative surface charge, causing no permselectivity for some cations as demonstrated by their lower than ideal cation transference numbers. Quantification of the surface charge density by XPS indicated the gold-plated membranes are highly charged due to Cl- chemisorption with a surface charge density of ~ 5.3 uC per cm2 corresponding to 3.3 x 1013 Cl--ions per cm2.
Characterization of the Reductive Desorption of Self-Assembled Monolayers on Platinum Surfaces
Authors: Martínez-Blanco Gilberto Josué , Casanova-Moreno Jannu
Published: July 2022

Thiol-based self-assembled monolayers (SAMs) have been widely characterized on gold surfaces, with the desorption potentials of these SAMs being of special interest for nanotechnology and biological applications. However, the study and determination of desorption potentials of thiol SAMs on platinum surfaces has been limited by the hydrogen evolution reaction (HER) catalyzed by the metal, which dominates response signals when studying the system through conventional electrochemical techniques.

Through the coupling of electrochemical techniques with fluorescence microscopy, the problem of the HER signal can be avoided in the study of desorption potentials for the platinum-thiol monolayer systems. By using fluorescent thiols, as well as monocrystalline platinum spheres, the desorption potential for different crystallographic orientations and thiol length combinations can be determined. The results obtained show that the desorption of Bodipy C10SH thiols from platinum surfaces occur at more positive potentials in [111] crystallographic orientations, and at more negative potentials at [100] ones. On the other hand, no notable difference was found in the desorption order of Bodipy C16SH from these two orientations.

However, the use of fluorescence microscopy for the solution of this problem poses other challenges: the time the thiols need to separate enough from the metallic substrate to not be affected by quenching, as well as the facts that thiols fluoresce less as they dilute and the existing spectral overlap for the molecules, adds difficulties to the establishment of the desorption potentials.

Through COMSOL Multiphysics simulations, we try to simulate the systems hereby proposed of platinum with thiol-based SAMs. Using them, the desorption potentials, as well as the monolayer coverage under specific conditions, can be determined. We expect that, with further development of the model, more specific values for these variables can be determined.

Figure 1
Electrochemical Observation and Analysis of Stochastic Single Nanoparticle Collisions on Ultramicroelectrode Using Pt, Ag, Cu, and Ni Nanoparticle
Authors: Kwon Seong Jung
Published: July 2022

We describe the electrochemical detection of single nanoparticle (NP) collision at an ultramicroelectrode (UME) with various NPs such as Pt, Ag, Cu, and Ni NP. We could observe the single NP collision through the enhanced current by electrocatalytic redox recycling. The overall current transient caused by the NP collision was differed depending on the NP collision system. The peak height and frequency of the current response are proportional to the size and concentration of the NP. The current response is very sensitive to the material and surface state of the measuring electrode. It also changed depending on the applied potential and the reaction mechanism of collided NP. Therefore, the current response was investigated at the various electrode material and surface state of the measuring electrode for better understanding of single NP collision mechanism and NP’s electrocatalytic reaction. For Pt and Ag NPs, the change of current response was mainly investigated with various experimental conditions. For Cu and Ni NPs, the new electrocatalytic reaction such as glucose oxidation and urea oxidation were applied. By observing and analyzing the various current response of the Pt, Ag, Cu, and Ni NP’s collision, the electrocatalytic activity of NP at various circumstance at a single NP level was studied.
Co Substitution of Cationic and Transition Metal in O3-Type NaCrO2 Cathode for High Energy Density
Authors: Oh Gwangeon , Kim Jaekook , Hwang Jang-Yeon
Published: July 2022

The development of advanced cathode materials with high operating voltage and high reversible capacity is essential to promote the practical realization of sodium ion battery (SIB) technology. Here, O3 type Na0.9Ca0.035Cr0.97Ti0.03O2 is designed by Ca and Ti co-substitution in O3 type NaCrO2, and proposed as a new type of cathode material for high-energy density practical SIBs. On the basis of Chemical science, Alkalin ion successully incorporate NaO6 octahedron of Na0.9Ca0.035Cr0.97Ti0.03O2.1,2 In substitution process two Na+ per single Ca2+, while Cr3+ to Ti4+ ions.3,4 As a result Na+ vacancies are formed Na+ layer. Through co-substitution, structural stability of O3 – Na0.9Ca0.035Cr0.97Ti0.03O2 is increased, because stronger Ti – O bond and immobile Ca2+ ions in Na site synergistically make an effect the unit cell structures. This structural feature suppresses the irreversible phase transition and provide fast Na ion kinetics. In 1.5 – 3.8 voltage range, O3 – Na0.9Ca0.035Cr0.97Ti0.03O2 cathode to deliver the high initial Coulombic efficiency of 95%. Also at a 10 C rate, cathode retains the 90% of its initial capacity after 1000 cycles. In situ X-ray diffraction confirmed the reversible structure properties during charging and discharging process. Moreover, the cathode guarantees the practical applicability with good cycling in a pouch- type full cell using a hard carbon anode, as well as with excellent water durability.

References

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J.-Y. Hwang, S.T. Myung and Y.K. Sun, Chem. Soc. Rev., 2017, 46, 3529–3614.

L. Zheng, J.C. Bennett and M.N. Obrovac, J. Electrochem. Soc., 2019, 166, A2058–A2064.

Y. Tsuchiya, K. Takanashi, T. Nishinobo, T. Ohta and N. Yabuuchi, Chem. Mater., 2016, 28, 7006–7016.
(Digital Presentation) Elucidating Electrolyte-Induced Performance Decay in Sodium-Tin Batteries
Authors: Sarkar Susmita , Mukherjee Partha P.
Published: July 2022

Tin (Sn) anodes for sodium-ion batteries have recently been extensively investigated due to their high capacity (847 mAh/g), low average operating potential (~250 mV vs. Na/Na+), environmental benignity, and high abundance. Unfortunately, upon repeated charging/discharging, both the Sn electrode and Na metal suffers from large volume changes that rupture the solid electrolyte interphase (SEI) and initiate the onset of cell failure. To understand such complex and interrelated phenomena, we have designed a 3-electrode cell to track the evolution of the electrochemical signature of both the working and counter electrode. Additionally, we have compared the electrode morphology and electrode/electrolyte interface under different electrochemical conditions and probed these morphological/interfacial changes with cycling life performance to cultivate a holistic understanding of different types of failure mechanisms. In particular, we have discussed whether the primary reason for the shorter cycling life is the mesoscopic/macroscopic deformation of the Sn electrode caused by volume expansion/contraction or the continuous formation/breakdown of SEI. Furthermore, the effect of a localized electrochemical environment, which primarily depends on the choice of electrolytes (ether-based and carbonate-based), is also explored here.
Designing a Li-N-H Based Solid Electrolyte
Authors: Lowen Jeremy Paul , Makepeace Joshua W
Published: July 2022

All-solid-state-batteries (ASSBs) have long promised to be the next-generation of high-performance energy storage devices, with a step-change in energy density, stability and cell safety touted as potential advantages compared to conventional Li-ion battery cells.[1] The development of fast lithium-ion conductors is key to realising commercially-viable ASSBs, however significant challenges remain with the leading candidate materials. Complex metal hydrides, in particular BH4
- derived materials, have gained recent attention due to their high ambient temperature lithium ionic conductivities and good stability with lithium metal.[2] Nitrogen-based complex hydrides, such as materials within the Li-N-H system, have largely been studied as solid-state hydrogen stores. However, a key characteristic that links the impressive properties of the Li-N-H system in this application is the high Frenkel defect-based Li-ion conductivity, which facilitates the formation of amide-imide and imide-nitride-hydride antifluorite structured solid solutions.[3,4] These solid solutions represent an opportunity through careful stoichiometry control to tailor the properties of a Li-N-H based material for application as a solid electrolyte.

Careful characterisation using X-ray diffraction and Raman measurements have allowed us to evaluate the structure of the solid solutions between lithium imide (Li2NH), lithium amide (LiNH2) and lithium nitride hydride (Li4NH), all dominated by a disordered anti-fluorite phase. We demonstrate the ability to tailor the conductivity of these materials between an ionic insulator and a superionic conductor by simple stoichiometry control. Lithium imide, and stoichiometries close to this compound, in particular display favourable properties as solid electrolyte materials. We herein exhibit the first demonstration of a Li-N-H material in an ASSB, with the materials displaying high lithium ion conductivities, wide electrochemical stability windows and potential for further tuning for this application.

Ultimately, these results identify Li-N-H based complex hydrides as an interesting avenue of research for solid electrolyte application that is yet to be fully explored. We hope this presentation will highlight these materials and spark further development such as has been seen for oxide and sulphide based fast-ion conductors.

1) Z. Zhang, Y. Shao, B. Lotsch, Y. Hu, H. Li, J. Janek, L F. Nazar, C. Nan, J. Maier, M. Armand and L. Chen, Energy Environ. Sci., 2018, 11, 1945-1976

2) A. Unemoto, M. Matsuo, and S. Orimo, Adv. Funct. Mater., 2014, 24, 2267-2279

3) W. Li, G. Wu, C. M. Araujo, R. H. Scheicher, A. Blomqvist, R. Ahuja, Z. Xiong, Y. Fengb and P. Chen, Energy Environ. Sci., 2010, 3, 1524-1530

4) J. W. Makepeace, J. M. Brittain, A. S. Manghnani, C. A. Murray, T. J. Wood and W. I. F. David, Phys. Chem. Chem. Phys., 2021, 23, 15091

Figure 1
Zinc-Ion Capacitors Working at Extreme Conditions
Authors: Xu Zhixiao , Wang Xiaolei
Published: July 2022

Combing advantages of both Zn anode and carbon cathodes, zinc ion capacitors (ZICs) hold great potentials for electrical vehicles and grid storage. To meet practical applications, high-mass-loading electrodes and harsh environment need to be considered when designing energy storage devices. For one, high-loading electrodes bring simultaneously the dense packing of active materials in limited space and the reduction of inactive components, leading to lower production cost and higher energy densities at the cell level compared with thin electrodes. That is why active mass loadings must be no less than 10 mg cm−2 for practical applications and typical values for commercial energy storage devices are 10-20 mg cm-2. However, this is not the case in most research papers with typical loadings of only 1-4 mg cm-2. On the other hand, low and high temperature environment will be encountered in not only extreme regions like North Pole and outer space but also residential areas with ever-changing climate. As such, it is critical to develop cells working in a wide-temperature range of −30 °C–50 °C for most human habitats and a broader range from −50 °C to 70 °C for military uses. Strangely, those two important factors are often ignored in the development of ZICs. In this work, we demonstrate workable ZICs under extreme conditions through the incorporation of activated carbon, aqueous binder and concentrated electrolyte. First, with highly exposed surface area and enriched oxygen, nitrogen dopants, the activated carbon manifests large electrical double layer capacitance and Faradic pseudocapacitance. Second, sodium alginate-based aqueous binder shows better electrolyte wettability than the commonly used polymer binder, resulting in much improved capacitance. Third, highly concentrated electrolyte enables large zinc stripping/plating efficiency, long life cycles as well as low frozen temperature due to reduced hydrogen bonding interaction of water. Three keys combined unlock ZICs with a large capacitance of 436 F g−1 (capacity: 200 mAh g-1), ultrafast kinetics, ultralong cycles, ultrahigh loadings (10 mg cm-2), and wide-temperature cycling (-60 oC ~ 60 oC), resulting in a maximum energy density of 134.8 Wh kg−1 and power density of 118.4 kW kg−1 based on AC electrode, which lies among the best performance level for carbon-based ZICs.
Temperature Dependent Study of AcFc-FeIII(acac)3 Redox Couple for Non-Aqueous Redox Flow Battery
Authors: Mazumder MD Motiur Rahaman , Islam Rezoanul
Published: July 2022

Energy storage is a vital aspect for the successful implementation of renewable energy resources on a global scale. Non-aqueous redox flow battery (NARFB) is one of the primary response to fulfill the next generation energy demand.1–6 This study describes the temperature dependence electrochemical analysis of acetyl ferrocene (AcFc) and iron(III) acetyl acetonate ([Fe(acac)3]) for NARFBs. An electrochemical cell consisting of AcFc and ([Fe(acac)3]) as catholyte and anolyte species, respectively, was constructed with a cell voltage of 1.41 V and Coulombic efficiencies >99% for up to 50 total cycles at 25o C (RT) and 0o C. Rotating ring disk electrode (RRDE) experiments suggest that diffusion coefficient decreases as the temperature decreases but overall storing capacity far better than aqueous redox flow battery (ARFBs). The electrochemical kinetic rate constant (k0) of AcFc found larger than Fe(acac)3 but remains similar at both temperatures. NMR study shows no structural change in changing temperature and after battery experiments.

References

(1) Mazumder, M. M. R.; Burton, A.; Richburg, C. S.; Saha, S.; Cronin, B.; Duin, E.; Farnum, B. H. Controlling One-Electron Vs Two-Electron Pathways in the Multi-Electron Redox Cycle of Nickel Diethyldithiocarbamate. ECS Meet. Abstr.
2021, MA2021-01 (1), 52–52. https://doi.org/10.1149/ma2021-01152mtgabs.

(2) Islam, R.; Mazumder, M. M. R.; Farnum, B. H. Solvent Dependent Spectroscopic and Electrochemical Studies of Nickel (II) Diethyldithiocarbamate for Energy Storage. ECS Meet. Abstr.
2021, MA2021-01 (1), 54–54. https://doi.org/10.1149/ma2021-01154mtgabs.

(3) Saha, S.; Sahil, S. T.; Mazumder, Md. M. R.; Stephens, A. M.; Cronin, B.; Duin, E. C.; Jurss, J. W.; Farnum, B. H. Synthesis, Characterization, and Electrocatalytic Activity of Bis(Pyridylimino)Isoindoline Cu( ii ) and Ni( ii ) Complexes. Dalton Trans.
2021, 10.1039.D0DT03030A. https://doi.org/10.1039/D0DT03030A.

(4) Mazumder, M. M. R.; Farnum, B. H. Two One Electron vs One Two-Electron Redox System of Nickel Diethyldithiocarbamate for Redox Flow Battery; ACS, 2021. https://doi.org/10.1021/scimeetings.1c00951.

(5) Mazumder, M. M. R.; Farnum, B. H; Burton Andricus. Mechanistic Study of Multi-Electron Redox Cycle of Nickel Dithiocarbamate Complex for Redox Flow Battery Application; ACS, 2021. https://doi.org/10.1021/scimeetings.1c00387.

(6) Mazumder, M. M. R. Ni(IV/II) Redox Couple 2e- Reversibility Improvement for Redox Flow Battery. ECS Meet. Abstr.
2021, MA2021-02 (5), 1855–1855. https://doi.org/10.1149/ma2021-0251855mtgabs.

Figure 1