bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) An Insight into the Reaction Mechanism of Organics on Palladium-Based Electrocatalysts
Authors: da Silva Rodrigo Garcia , de Andrade Adalgisa Rodrigues , Servat Karine , Morais Claudia , Napporn Teko , Kokoh Boniface 
Published: July 2021

Alcohols are promising renewable and sustainable fuel alternatives for low-power energy devices. As the number of carbons in this type of fuel increases, the power density decreases, but in parallel with the generated energy, the capacity of recovering value-added products in cogeneration increases as well 1,2. In this context ethylene glycol, glycerol and glucose were investigated on nickel and ruthenium modified palladium nanocatalysts with electrochemical, spectroelectrochemical, and chromatographic methods. These carbon-supported materials prepared by a revisited polyol approach coupled with microwave irradiation exhibited high activity towards the ethylene glycol electrooxidation in alkaline medium. Long-term electrolysis conducted in a batch three-electrode cell, coupled with High Performance Liquid Chromatography/Mass Spectrometry (HPLC-MS) and in situ Fourier Transform Infrared Spectroscopy (FTIRS) measurements permitted the determination and the identification of the compounds electrogenerated in the oxidative conversion of this two-carbon molecule. Addition of Ni to the Pd-based catalyst results in bimetallic compositions with a metal loading that changes away from the theoretical one as the Ni content increases. In terms of catalytic activity, the presence of Ni provides a strain effect at low content, giving way rather to a surface restructuring effect which predominates when the Ni content is raising (Ni50@Pd50/C). Molecules such as oxalate, glyoxylate, and glycolate were identified in all the electrolytic solutions, while glyoxylate was selectively formed at the Ru45@Pd55/C electrode surface. In situ FTIRS results also showed a decrease of the pH value in the thin layer near the electrode as a consequence of OH- consumption during the spectroelectrochemical experiments. The concentrations of the reaction products are slightly higher at the Ru45Pd55/C surface, where the electronic effect of Ru on the d-band center of Pd was clearly marked by the shift of the ethylene glycol oxidation towards the lower potentials. These results will serve as guidelines for future work related to potential applications of ethylene glycol in fuel cell devices, promoting cogeneration of high value-added products.
Acknowledgements: This work was mainly conducted in the framework of the collaborative program CAPES/COFECUB under grant n° 914/18. The authors also acknowledge the financial support from FAPESP (grants number 2013/25632-0), the European Union (ERDF), and EDF.
References
1. Y. Holade, K. Servat, T. W. Napporn, C. Morais, J.-M. Berjeaud, K. B. Kokoh, ChemSusChem, 9, 252 (2016).
2.Y. Holade; N. Tuleushova, S. Tingry, K. Servat, T. W. Napporn, H. Guesmi, D. Cornu, K. B. Kokoh, Catal. Sci. Technol., 10, 3071 (2020).
Key Role for Nonlinear Phenomena of Li-O2 Batteries in Discharge Properties
Authors: Hase Yoko 
Published: July 2021

Li-O2 batteries have attracted much attention as one of the candidates of future energy devices because of their ultimate energy density. This specific property of Li-O2 batteries is derived from the discharging reactions, which consist of the dissolution of Li metal of anode and oxygen reduction reaction (ORR) on the cathode.1-3 However, many issues to apply them for practical use, such as the limited capacity and low energy efficiency, have remained undissolved. In typical Li-O2 batteries, carbon materials are applied as cathodes on which the discharge product, Li2O2, forms and deposits. Due to the inherently low electron conductivity of Li2O2, deposition on the cathode prevents continuous discharge, and causes the cell voltage to drop sharply during constant current discharging. This nonlinear phenomenon, which is called “Sudden cell death”, is known to restrict the discharge capacity of Li-O2 batteries.
Herein, we present that the negative differential resistance (NDR), which appears in the ORR of Li-O2 batteries, plays a key role in the discharge properties.4-6 The existence of NDR in the potential region of discharge implies that LiO2, which is an intermediate of the discharge reaction, impedes the ORR and its coverage varies with the cell voltage. Since LiO2 is desorbed from the cathode at higher cell voltage than NDR region, ORR proceeds via “the solution pathway” where Li2O2 forms in the electrolyte is promoted. Meanwhile, the lower cell voltage leads “the surface pathway” in which the adsorbed LiO2 is further reduced to Li2O2 on the cathode surface. Therefore, these results rationally revealed that there is a transition of pathways from the solution to the surface in the galvanostatic discharging process, and this transition causes “Sudden cell death”. The cell voltage where the transition region of reaction pathways appears shifts with cathode materials and electrolytes, therefore, the design of appropriate condition of usage is important to induce the maximum performance of Li-O2 batteries.
References
1) A. C. Luntz, B. D. McCloskey, Chem. Rev.,
114, 11721-11750 (2014).
2) C. Shu, J. Wang, J. Long, H. K. Liu, S. X. Dou, Adv. Mater., 31, e1804587 (2019).
3) W. J. Kwak, Rosy, D. Sharon, C. Xia, H. Kim, L. R. Johnson, P. G. Bruce, L. F. Nazar, Y. K. Sun, A. A. Frimer, M. Noked, S. A. Freunberger, D. Aurbach, Chem. Rev., 120, 6626-6683 (2020).
4) Y. Hase, Y. Komori, T. Kusumoto, T. Harada, J. Seki, T. Shiga, K. Kamiya, S. Nakanishi, Nat. Commun., 10, 596 (2019).
5) K. Nishioka, K. Morimoto, T. Kusumoto, T. Harada, Y. Hase, K. Kamiya, S. Nakanishi, Chem. Lett., 48, 562-565 (2019).
6) Y. Hase, K. Nishioka, Y. Komori, T. Kusumoto, J. Seki, K. Kamiya, S. Nakanishi, J. Phys. Chem. Lett., 11, 7657-7663 (2020).
The Efficiency of the Electro-Oxidation of Small Organic Molecules: Oscillations and Mechanism
Authors: Varela Hamilton 
Published: July 2021

Many hydrogen-carriers have been considered for the direct use in fuel cells and also in the electrochemical reform, where they are oxidized instead of water at lower potentials. We have investigated the electro-oxidation of formaldehyde, formic acid, methanol, and ethanol,[1] and of ethylene glycol, glycerol, and glucose[2] on polycrystalline platinum in acidic media, and compare the activity under conventional and oscillatory regimes. The comparison is carried out by different means and generalized by the use of simple identical experimental conditions in all cases. The activity along slow potentiodynamic curves, inferred by the peak current, decreases in the following sequence: formaldehyde ~ formic acid > methanol > ethanol ~ ethylene glycol > glucose > glycerol. The ubiquitous occurrence of potential oscillations under galvanostatic regime is associated with excursions of the electrode potentials to lower values, which noticeably decreases the overpotential of the anodic reaction, when compared to that in the absence of oscillations. Considerable enhancement in the power density was observed in an idealized fuel cell operated with those fuels when operated under oscillatory regime. Furthermore, the spontaneous periodic self-cleaning processes, present important advantages to the use of autonomous oscillations to reach both higher and long-term activities, and stability [3]. The discussion of these half-cell studies is complemented with experiments with proton exchange membrane fuel cells, namely direct liquid fuel cells (DLFCs). We have investigated the effect of temperature on DLFCs under conventional and oscillatory conditions.[4] Methanol, formic acid, ethanol, and dimethyl ether (DME) were used as fuels and identical experimental conditions were used in all cases. Some findings observed in half-cells are also observed in the DLFCs studied, but few peculiarities of the experimental configuration adopted in the later arise. Finally, mechanistic aspects underlying the observed dynamics are discussed.
[1] M. V. F. Delmonde, L. F. Sallum, N. Perini, E. R. Gonzalez, R. Schlögl, H. Varela, J. Phys. Chem. C
120 (2016) 22365.
[2] G. B. Melle, T. A. Ferreira, R. L. Romano, H. Varela, in preparation (2020).
[3] J. A. Nogueira, P. P. Lopes, N. M. Markovic, H. Varela, Electrochem. Commun.
121 (2020) 106853.
[4] J.A. Nogueira, H. Varela, Energy Fuels
34 (2020) 12995.
(Invited) Probing the Electronic Structure of Oxide Electrocatalysts and the Formation of Reaction Intermediates
Authors: Stoerzinger Kelsey A 
Published: July 2021

Perovskite oxides (ABO3) are highly active for the oxygen evolution reaction (OER). Activity is observed to correlate with changes in bulk electronic structure parameters, such as metal-oxygen covalency and transition metal oxidation state. We employ spectroscopic approaches to consider such descriptors at the surface of perovskite oxides in situ, as well as their implications on the formation of surface adsorbates proposed to act as reaction intermediates during the OER.
Many surface science techniques, such as X-ray photoelectron spectroscopy (XPS), collect information from inherently surface-sensitive low-energy processes, requiring operation in ultrahigh vacuum. This constraint is lifted for ambient pressure XPS, which can probe the surface in equilibrium with the gas phase at pressures up to ~a few Torr, or with thin liquid layers using a higher incident photon energy. This presentation will discuss the insights obtained with this technique regarding the electronic structure of oxide electrocatalysts in an oxidizing or humid environment, as well as the reaction intermediates of relevance to electrocatalysis.1 We will then extend the technique to probe electrocatalysts in operando,2 driving current through a thin layer of liquid electrolyte and employing a tender X-ray source.
References:
[1] Stoerzinger,K.A.Wang, L. Ye, Y. Bowden, M. Crumlin, E.J. Du, Y. Chambers, S.A. “Linking surface chemistry to photovoltage in Sr-substituted LaFeO3 for water oxidation”. Journal of Materials Chemistry A 6 (2018) 22170-22178.
[2] Stoerzinger, K.A. Wang, X.R. Hwang, J. Rao, R.R Hong, W.T Rouleau, C.M. Lee, D. Yu, Y. Crumlin, E.J. Shao-Horn, Y. “Speciation and electronic structure of La1-xSrxCoO3-δ during oxygen electrolysis”. Topics in Catalysis 61 (2018) 2161–2174.
Oxygen Evolution Reaction Enables Better Performance for Aqueous Na-Ion Batteries
Authors: Zhang Yuxin , Lin Feng 
Published: July 2021

Aqueous batteries have attracted intensive attention owing to their inflammable water-based electrolyte. However, the upper cut-off voltage is significantly limited by the oxygen evolution reaction (OER) induced by water decomposition, which undermines the energy density of most aqueous batteries. OER not only consumes electrolytes but also leads to severe side reactions between generated oxygen and electrodes, resulting in rapid capacity decay. One of the most important aspects in maintaining a long aqueous battery lifetime is to suppress oxygen gas generation or eliminate oxygen gas in the cell. Although the negative effects of OER are well accepted, the positive influence is still ambiguous. In this presentation, we will discuss how properly manipulating OER can serve as an approach to improving the performance of aqueous batteries.
Na-deficient Prussian Blue (PB) cathodes are undesired for aqueous full-cells due to the insufficient amount of cyclable Na-ions and inferior specific capacity. Our study will demonstrate that the performance of Na-deficient PB cathodes based full cells can be improved by OER. Relying on the two-electrode glassware cell composed of Na-poor PB cathode and NaTi2(PO4)3 (NTP) anode, the bubble generation on the cathode was directly observed during overcharging process, confirming the occurrence of OER at high charging states. After the overcharging protocol was applied to the coin cell during the first cycle, the discharge capacity was elevated from 55 mAh/g, which originates from low Na content in the pristine cathodes, to 130 mAh/g. Further analysis on structural evolution and charge compensation mechanisms revealed that, accompanying the OER on the cathode, Na ions in the electrolyte get inserted into the NTP anode during overcharging process, resulting in more cyclable Na-ions in the full cell system and thus enhancing the discharge capacity. On the other hand, owing to the pH gradient on the cathode surface caused by water decomposition, transition metal dissolution was reported through X-ray fluorescence mapping, leading to the declined Coulombic efficiency. Our study illustrates the potential utilization of overcharging protocol and offers fundamental insights into the influence of oxygen evolution reaction in aqueous batteries.
Exploring Iron Oxides Anodes By Tuning Their Structure and Morphology for Lithium-Ion Batteries
Authors: Hagerman Tanner Gardell , Ketelsleger Cameron , Gregory Darrell , Walters Keisha , Abbott Brandon , Capraz Omer Ozgur Özgür 
Published: July 2021

Demand for lithium-ion batteries is increasing with the increase in portal electronic, electric vehicle and renewable energy. High energy dense electrode materials are required to meet this demand. In this study we are exploring an alternative anode material to graphite electrodes. We chose Iron Oxides due their abundancy and high capacity1 .
We altered the structure and morphology of iron oxide nanoparticles (IONP) and prepared electrodes from the following nanoparticles (NP): Commercial iron (III) oxide NP (Fe2O3), iron oxide NP + succinic acid, iron oxide NP + citric acid, silica-encapsulated Fe3O4 NP and iron oxide NP + perchloric acid. Slurries were made using a conductive carbon (Super P) carboxymethyl cellulose and ultra-pure water in a weight ratio of 8:1:1 (w/w). Lithium perchlorate (1 M) was dissolved in ethylene carbonate and dimethyl carbonate and used as the electrolyte. Using an ARBIN battery test unit, cyclic voltammetry was performed between 0.05 and 3.0 V and compared to a lithium counter electrode at a scan rate of 0.1 mV/s. Figure 1 compares the electrochemical performance of these iron oxide anodes with different structure and morphology.
This was supported by Oklahoma State University’s CEAT undergraduate research scholarship.
[1] Wang, X. et al (2016). Uniform Fe3O4 microflowers hierarchical structures assembled with porous nanoplates as superior anode materials for lithium-ion batteries. Elsevier Applied Surface Science vol (389) 240-246. Doi: 10.1016/j.apsusc.2016.07.105

Figure 1
Analysis of Iron (III) Perchlorate at Magnetically Modified Electrodes
Authors: Dadallagei Kasun Saweendra Rathnatunga , Leddy Johna 
Published: July 2021

Electrochemical reactions drive many chemical processes using well established protocols and hardware. Most improvements of electrochemical reactions require substantial changes to existing protocols and equipment, However, our previous work has shown that electrochemical systems may be impacted by the presence of magnetic field gradients at the electrode surface. Using ion exchange polymer films with embedded magnetic microparticles, it is possible to improve reaction kinetics. Previous cyclic voltammetric studies of metal tris-bipyridine complexes at electrodes modified with composite films of Nafion and magnetized microparticles exhibit substantially higher currents than at electrodes modified with simple Nafion films.
The aim of this study is to show magnetic field gradients can enhance currents for redox probes other than metal tris-bipyridine complexes and to use methods alternative to cyclic voltammetry (CV). Iron (III) perchlorate is the first transition metal species evaluated by impedance to exhibit enhanced electron transfer rates at electrodes modified with magnetized microparticles in Nafion. The enhancement is attributed to improvements in kinetics of heterogeneous exchange rate and self exchange rate.
Electrochemical impedance spectroscopy (EIS) and CV studies at magnetically modified electrodes are compared to non-magnetic analogs for the iron (III) perchlorate redox couple. This redox couple shows kinetic rate enhancements for the magnetically modified electrodes over the non-magnetic analogs.
(General Student Poster Session Winner - 1st Place) An Algorithm for Fitting Tafel Data and Determining Kinetic Parameters
Authors: Coduto Joshua Richard , Leddy Johna 
Published: July 2021

Tafel analysis is widely used to characterize electrochemical kinetics and assess the properties of electrocatalysts for use in fuel cells, electrolyzers, and other applications. Conventional Tafel analysis is an extension of the Butler-Volmer equation at high overpotentials under conditions where mass transport is not significant and the reverse reaction rate is negligible compared to the studied half-reaction. Determination of kinetic parameters from a Tafel plot involves linear regression in regions of large overpotential. This method is limited in part by the subjective determination of linearity, as the kinetic parameters obtained by the regression may vary significantly depending on the chosen linear region.
In an effort to increase measurement quality and decrease subjectivity, an algorithm has been developed that generates a Tafel plot from a linear sweep voltammogram (LSV) and determines the exchange current density j
0, charge transfer coefficient α, and Tafel slope of closest fit. Comparisons of kinetic parameters between conventional and algorithmic Tafel analysis are made for the hydrogen evolution reaction (HER, 2H+ + 2e- → H2) on different metal electrodes and Nafion® composite electrodes. The algorithmic Tafel analysis parameters correlate well with conventional methods. Similar agreement is observed between literature and algorithmically fitted kinetic parameters for different electrochemical systems. The developed algorithm allows for straightforward, rapid, and user bias independent Tafel analysis and can be easily used to increase measurement quality.
Characterizing Materials and Electrochemical Changes in a Range of 18650 Li-Ion Cells Cycled to 80% Initial Capacity
Authors: Wittman Reed M , Dubarry Matthieu , Ivanov Sergei , Fresquez Armando , Langendorf Jill , Grant Richard , Taggart Gretchen , Chalamala Babu , Preger Yuliya 
Published: July 2021

Understanding systematic trends in degradation of Li-ion batteries through a broad range of operating conditions is critical to improving their performance. Over the course of the last few years, researchers at Sandia National Labs have been conducting a systematic study of battery cycling behavior. In this study, dozens of commercial NCA (LiNixCoyAl1-x-yO2) and NMC (LiNixMnyCo1-x-yO2) cells were cycled to 80% capacity across a range of temperatures, discharge rates, and depth of discharge windows. Analysis of both in situ electrochemical data and postmortem materials degradation was done and correlated to determine root causes of rapid capacity fade.
During cycling, Electrochemical Impedance Spectroscopy (EIS) and Incremental Capacity Analysis (ICA) experiments were conducted periodically. The data from these experiments were used to understand the state of health (SoH) of cycling cells, including SEI formation and Li plating, as well as general mass transport and kinetic properties.
X-ray Computed Tomography (XCT) scans completed before cell disassembly showed large scale deformation in the cells’ jelly rolls. For the postmortem analysis, cells in pristine condition and 80% capacity were disassembled, and their electrodes were analyzed with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC). These techniques analyzed different aspects of the electrodes’ physical and chemical properties, including Li plating, micro-cracking, SEI layer formation, and phase changes in cathode materials. DSC measurements also provided insight into changes in the degree to which aged electrodes undergo thermal runaway events.
Correlation of the postmortem materials analysis with the in situ electrochemical analysis showed that cells with the most rapid rate of capacity fade had multiple degradation mechanisms active during cycling. The scale of this electrochemical and materials evaluation fills in gaps in the literature about commercial Li-ion battery performance.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
3D Printed Hydrogel-Based Sensors for UV Sensing Applications
Authors: Finny Abraham Samuel , Jiang Cindy , Andreescu Emanuela 
Published: July 2021

The development of additive manufacturing techniques to manufacture sensors rapidly and cost-effectively would benefit healthcare, environmental monitoring, food, and cosmetic industries. Because of the inherent complexity of sensing devices, new fabrication methods that utilizes recent advances in additive manufacturing to create sensors on a large scale efficiently are necessary. Techniques like 3D printing and 3D bioprinting enable printing different biomaterials into intricate 3D architectures that could serve as sensing platforms. This presentation will describe 3D printed hydrogel-based sensors’ development and optimization with incorporated receptor molecules and transduction interfaces for UV sensing1. To 3D print these sensors, an extrusion-based 3D bioprinter and a computer-aided designing software were used along with a novel bio-ink formulation. The bio-ink formulation contains nanoparticles with photocatalytic properties and degradable dyes dispersed homogeneously within a mechanically stable hydrogel network. The optimum hydrogel composite provides excellent mechanical properties to the printed sensors, enabling them for many applications. The proposed sensors are reagent-less and highly portable, making them ideal for wearable devices and printed platforms for portable bioelectronics. Apart from their ability to be used as wearable sensors, these sensors also have the potential to be used simultaneously with UV-based workspace sterilizing devices to guarantee that surfaces are adequately exposed to UV. The sensors are cheap, durable, robust, biodegradable, and simple to use. The tunable, biocompatible, and printable properties of the ink offer great potential for developing advanced 3D printing methods that, in addition to UV sensors, can be applied more broadly to fabricate other sensing technologies for various other applications.
1. A. S. Finny, C. Jiang, and S. Andreescu, ACS Applied Materials & Interfaces, 12, 43911–43920 (2020).

Figure 1