bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Insights into Volcano Correlations of the Oxygen Reduction Reaction with MN4 Catalysts
Authors: Matute Ricardo A. , Zagal Jose H 
Published: December 2020

The design of metal complex catalysts for the oxygen reduction reaction (ORR) [1] can be assisted with the use of computational chemistry and Quantum Mechanics (QM) methods. In this work, we have implemented theoretical models and have used the computational chemistry for the rational design of MN4 catalysts with optimal catalytic efficiency for ORR. The application of ab initio and DFT-based methodologies were employed to assess binding energies on the interaction of O2 and the metal center of MN4 systems. [2] The energetic assessment on reactive paths has proved to be affected, in organic systems, by dynamical effects and strongly influenced by the electronic structure of substituents [3,4]. Hence, the electrocatalytic performance of porphyrins and phthalocyanines were assessed by the analysis of volcano correlations against computed binding energies. In these plots, substitution patterns on the catalysts include both in-plane and axial ligands. Besides the binding energies, other descriptors were assessed as well (e.g., the DFT-based hardness). The systematic study of volcano plots provided a deeply understanding on the the pivotal role of the ligands and the nature of electronic effects underlying the Sabatier principle for the electrocatalysis of the ORR by MN4 molecular systems.

Acknowledgements

The authors want to acknowledge the funding of Anillo Project ACT 192175

References

[1] A. Kulkarni, S. Siahrostami, A. Patel, J. K. Nørskov, Chem. Rev.
2018, 118, 2302.
[2] J.H. Zagal, M.T.M. Koper, Angew. Chem. Int. Ed.
201
6, 5
5, 14510.
[3] R.A. Matute and K.N. Houk, Angew. Chem. Int. Ed., 2012, 51, 13097.
[4] D.E. Ortega, R.A. Matute, J. Phys. Chem. A
2020, 124, 3573.
Spectroelectrochemistry of Non-Aromatic Explosives in Acetonitrile and the Influence of Superoxide
Authors: Holubowitch Nicolas , Budimir Zachary 
Published: December 2020

The spectroelectrochemistry of non-aromatic explosive compounds, namely two nitramines (RDX and HMX), a nitrate ester (PETN), and a plastic explosive composite (Semtex 1A) in acetonitrile (AN) is reported. The redox behavior of these compounds is studied using cyclic voltammetry while monitoring changes in UV absorbance to identify transient intermediates and product species. In search of a low-cost solution-phase detection technique for explosives, we compare the spectroelectrochemistry of these compounds in the presence and absence of naturally dissolved oxygen (2 mM in AN), where the superoxide radical is co-electrogenerated during analyte reduction. Free superoxide yields a prominent UV signal in this medium (λmax = 250 nm) that the explosives’ nitro or methylene groups attenuate stoichiometrically. Overlapping UV spectra of multiple species are deconvoluted using a new strategy, spectral regional baselining, for time- and potential-resolved spectroelectrochemical (SEC) analysis. SEC data for nitrite (NO2
-), nitrate (NO3
-), and nitromethane (CH3NO2) were also collected to support proposed reaction mechanisms for the transformation of explosives that include superoxide adducts and dimerized azoxy reduced intermediates. The findings expand the understanding of high-explosive solution-phase chemistry and offer a route to novel signal transduction for (electro-)chemical sensors for energetic materials.
Figure 1. Spectroelectrochemistry of PETN in aerated acetonitrile with regions denoted for differential baseline analysis. (a) 3-D projected cyclic voltammogram (black) with UV absorbance from relevant wavelength (red, unscaled) as a function of time and potential; (b) full spectra (time domain) during cyclic voltammogram.

Figure 1
A Sensitive Urea Sensor Based NiO Nanoparticles Supported on the 3D Porous Carbonized Eggshell Membrane
Authors: Lu Shun , Gu Zhengrong 
Published: December 2020

Urea (CO(NH2)2) is the main nitrogen-containing substance from the urine of human/animal, which is also an effective and critical indicator in evaluating various metabolic disorders. Urea can decompose naturally to toxic ammonia and nitrates permeating into groundwater, then cause environmental problems and even health issues. Therefore, the detection of urea concentration and decomposition of urea-rich sewage is vitally important in the human health and environmental industries. Urea oxidation reaction (UOR, CO(NH2) 2 + 6OH- → N2 + CO2 + 5H2O + 6e-) has been known as a viable method for renal/liver disease diagnostic detection. Here, we reported nickel oxide (NiO) nanoparticles dressed on the carbonized eggshell membrane (3D NiO/c-ESM) as a modified electrode toward urea detection. The unique network structure of ESM composed of biomacromolecular fibers provides a novel template for the functional groups, also with superior porosity and specific surface area, which can offer multiple transport pathways for both electrons and ions.
Consequently, an integrated 3D network composed of NiO nanoparticles anchoring on the carbonized ESM using a mixed method of hydrothermal and pyrolysis. The NiO nanoparticles anchored 3D carbonized network of the catalyst provides more catalytic active sites and enables easy access of reactants to the catalyst surfaces. NiO/c-ESM modified electrode exhibits an outstanding performance for urea determination with a linear range from 0.05 to 2.5 mM, and limit detection of ∼20 µM (3σ). This work offered a green approach for introducing 3D nanostructure through employing biowaste ESMs as templates, providing a typical example for producing new value-added nanomaterials with urea detection.
(Invited) Multi-Modal Operando Analysis of Lithium-Solid Electrolyte Interfaces
Authors: Dasgupta Neil P. 
Published: December 2020

Solid-state batteries (SSBs) have the potential to revolutionize energy storage by increasing energy density and improving safety compared to state-of-the-art Li-ion batteries with liquid electrolytes. However, the formation of solid-solid interfaces poses unique challenges compared to solid-liquid interfaces. This requires new methods to study the fundamental behavior of solid-solid interfaces, and understand their dynamic evolution during cycling1.
In this talk, I will present a suite of multi-modal in situ/operando characterization approaches that we have used to study Li metal-solid electrolyte interfaces during cycling. First, to gain an improved understanding of the electrochemical stability, I will discuss operando X-ray photoelectron spectroscopy (XPS) analysis of lithium metal-solid electrolyte interfaces2. This approach allows us to directly observe interphase formation and evolution as the electrochemical potential of the solid-electrolyte surface is biased to potentials below the thermodynamic potential for Li plating. A range of sulfide and oxide ceramic electrolytes were explored, since they exhibit a range of (in)stability levels during Li metal plating.
To compliment these spectroscopic measurements, a range of in situ/operando microscopy techniques will also be presented. First, operando optical microscopy results will be presented, which allow for direct observation of the nucleation and growth of Li filaments both into, and out of, solid electrolyte surfaces2-3. By time synchronizing the optical video analysis with the electrochemical signatures of plating and stripping, new insights into the dynamic evolution of morphology and associated electrochemical analysis can be obtained. This micro-scale imaging will also be complimented by in situ analysis at the nanoscale, through a combination of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By integrating the observations across this multi-modal characterization approach, the implications for SSB performance and stability will be discussed, and critical needs for future research will be described.
1) K. B. Hatzell, X. C. Chen, C. L. Cobb, N. P. Dasgupta, M. B. Dixit, L. E. Marbella, M. T. McDowell, P. P. Mukherjee, A. Verma, V. Viswanathan, A. S. Westover, W. G. Zeier “Challenges in Lithium Metal Anodes for Solid State Batteries” ACS Energy Lett.
5, 922 (2020).
2) A. L. Davis, R. Garcia-Mendez, K. N. Wood, E. Kazyak, K.-H. Chen, G. Teeter, J. Sakamoto, N. P. Dasgupta “Electro-Chemo-Mechanical Evolution of Sulfide Solid Electrolyte/Li Metal Interfaces: Operando Analysis and ALD Interlayer Effects” J. Mater. Chem. A
8, 6291 (2020).
3) E. Kazyak, R. Garcia-Mendez, W. S LePage, A. Sharafi, A. L. Davis, A. J. Sanchez, K.-H. Chen, C. Haslam, J. Sakamoto, N. P. Dasgupta “Li Penetration in Ceramic Solid Electrolytes: Operando Microscopy Analysis of Morphology, Propagation, and Reversibility” Matter
2, 1 (2020).
Free-Standing Garnet-Type Solid Electrolyte Separators Fabricated By Water-Based Tape-Casting
Authors: Ye Ruijie , Finsterbusch Martin , Figgemeier Egbert 
Published: December 2020

The garnet-type Li-ion-conductor Li7La3Zr2O12 (LLZO) is regarded as a promising oxide-ceramic based solid electrolyte (SE) material for all-solid-state lithium ion battery (Li-ASB) owing to its wide electrochemical stability window, chemical stability versus Li metal and excellent conductivity. However, one of the challenges regarding the fabrication of such ASBs is the industrial scalability of manufacturing methods. Tape-casting of ceramic components is known e.g. from SOFC manufacturing to enable the large-scale production of free-standing ceramic components and cells with low thickness. Additionally, in conventional tape-casting, organic solvents are usually employed, which give rise to health and safety issues and lead to high cost for solvent recovery. Hence, development of a green, water-based processing route is favorable.
Herein, we report an aqueous tape-casting process of LLZO separators using a water-soluble biopolymer as binder. A lattice expansion of LLZO is observed by X-ray diffraction in aqueous green tape due to the partial replacement of Li+ by H+, whereas the lattice parameter of LLZO in sintered sheet decreases to the same value of pristine LLZO powder, indicating the Li-recovery in the LLZO structure after sintering. This observation confirms that the Li+/H+-exchange reaction is reversible during the aqueous processing. The obtained free-standing LLZO sheet after sintering shows high ionic conductivity observed by impedance spectrometry in Li/LLZO/Li symmetric cell at room temperature, which is comparable with reported thin garnet separators fabricated by conventional non-aqueous tape-casting.
In summary, we successfully fabricate self-supporting LLZO sheet with high ionic conductivity by aqueous tape-casting process, which is enabled by reversible Li+/H+-exchange. This free-standing LLZO sheet can be later used as separator in the Li-ASBs having an electrolyte-supported configuration.
Reaction Kinetics of Zn2+ with Radiolysis Products in Molten LiCl-KCl Eutectic
Authors: Iwamatsu Kazuhiro , Horne Gregory P. , Gakhar Ruchi , Phillips William C. , Halstenberg Philip , Layne Bobby H. , Pimblott Simon M. , Wishart James F. 
Published: December 2020

A thorough understanding of radiation effects on molten salt media is necessary to support the design, development, and deployment of molten salt reactor, using either fuel salt or solid fuel with salt as the coolant. Fundamental issues include the determination of the initial yields and reactivity of the primary radiolytic species, i.e., the solvated electron (esolv
–), chlorine atom (Cl•), and dichloride radical anion (Cl2
•–) as their reactivity varies depending on the environment such as the salt cation and temperature. Here we report on the reaction kinetics for esolv
– and Cl2
•– in molten LiCl-KCl eutectic doped with Zn2+ ions. Electron pulse radiolysis absorption spectroscopy was used to observe the transient behavior of esolv
– and Cl2
•– on the nanosecond to microsecond time scale. Experiments were performed using the Brookhaven National Laboratory Laser-Electron Accelerator Facility (LEAF)1 and utilizing a recently developed high-temperature sample holder.2 Decay kinetics of of esolv
– and Cl2
•– in 9.41 mM ZnCl2 in LiCl-KCl are shown in the figure. esolv
– and Cl2
•– decays in different time scale due to different reaction kinetics and decay speed increase as temperature.
This work was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy (US-DOE), Office of Science, Basic Energy Sciences, at BNL, INL and ORNL under contracts DE-SC0012704, DE-AC07-05ID14517 and DE-FC02-04ER15533, respectively. The Laser Electron Accelerator Facility of the BNL Accelerator Center for Energy Research is supported by the US-DOE Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704.

Wishart, J. F.; Cook, A. R.; Miller, J. R.; Rev. Sci. Instrum., 2004, 75 (11), 4359.

Phillips, W. C.; Layne, B.; Gakhar, R.; Horne, G. P.; Ramos-Ballesteros, A.; Iwamatsu, K.; LaVerne, J. A.; Pimblott, S. M.; Wishart, J. F.; Rev. Sci. Instrum., 2019, in peer review.

Figure 1
Electrochemical Behavior of the SmF3 in Alkali Chloride Melts
Authors: Stuliov Yuriy V. , Kuznetsov Sergey A. 
Published: December 2020

Today, existing methods of recycling spent nuclear fuel do not solve the problem of separation of transuranium elements and lanthanides. Electrolysis of molten salts is promising for separation of lanthanides and actinides. To solve this problem, it is necessary to have experimental data on the electrochemical behavior of various lanthanides in molten salts.
The aim of this study is the electrochemical investigation by cyclic voltammetry of the Sm(III)/Sm(II) redox couple in NaCl-KCl, KCl and CsCl melts containing SmF3.
Electrochemical studies were carried out in a temperature range of 973-1173 K by cyclic voltammetry using an AUTOLAB PGSTAT 20 potentiostat with a package of application programs GPES (version 4.4.). The sweep rate (v) varied between 0.1 up to 3.0 V s-1. The melt container was a glassy carbon crucible of SU-2000 brand, which also served as an auxiliary electrode. Tungsten wire was used as a working electrode and platinum wire was utilized as a quasi-reference electrode.
It was found in NaCl-KCl-SmF3, KCl-SmF3 and CsCl-SmF3 melts that the recharge process was reversible up to the scan rate 1.0 V s-1. In this range of sweep rate the diffusion coefficients (D) of Sm(III) were calculated using the Randles–Shevchik equation. The diffusion coefficients decrease with a change of the composition of the second coordination sphere from sodium to cesium. Similar dependencies for D values are well known. It is associated with a decrease of the counter-polarizing effect during the transition from Na to Cs, which in turn causes a decrease of the metal – ligand bond length and increase the strength of samarium complexes.
A transition from reversible to quasi-reversible process was found at v > 1.0 V s-1 in NaCl-KCl-SmF3, KCl-SmF3 and CsCl-SmF3 melts.
The standard rate constants of charge transfer (k
s) of the redox couple Sm(III)/Sm(II) were determined by cyclic voltammetry in all studied melts by using the Nicholson’s equation, which is valid for quasi-reversible processes.
The following series of the standard charge transfer constants was found k
s(CsCl)<k
s(KCl)<k
s(NaCl–KCl). According to the theory of elementary charge transfer, the smaller and stronger bond complexes require a higher rearrangement energy, and in consequence, the charge transfer proceeds at a slower rate. Therefore, a decrease of the standard rate constants for the redox reaction would have been expected, which is in an agreement with obtained experimental results.
Molten Salts Based Electrochemical Approach to Regenerative Fuels
Authors: Chen George Zheng 
Published: December 2020

Electrochemical energy storage (EES) technologies, such as rechargeable batteries, supercapacitors and supercapatteries, are featured by their capability of direct storage of electricity, fast charging-discharging, and modular flexibility and convenience for scaling [1,2]. However, they also suffer from several obvious shortcomings, for example, high manufacturing cost, low specific energy (or energy density), and short storage time in comparison with technologies based on combustion of fossil fuels. In fact, the specific energy values resulting from either thermochemical or electrochemical oxidation are very much comparable, considering the thermodynamics of the following common reactions that convert chemical energy in the fuels to work, i.e. Gibbs energy change. Therefore, the key to increase the specific energy of EES technologies depends largely on how to achieve the conversion.

Reaction number

Energy conversion reactions

Maximum work (Gibbs energy change)

(1)

H2 + O2 = H2O(g)

9.9 (88.8) kJ/g

(2)

C + O2 = CO2

9.0 (33.3) kJ/g

(3)

CH4 + 2O2 = CO2 + 2H2O(g)

10.0 (50.0) kJ/g

(4)

4Li + O2 = 2Li2O

14.3 (30.8) kJ/g

(5)

Al + O2 = Al2O3

12.5 (23.5) kJ/g

(6)

Si +O2 = SiO2

11.4 (24.3) kJ/g

The values given in brackets are calculated without considering the mass of oxygen gas.
In these oxidation reactions, the reactants are the fuels that can all be reproduced or regenerated from the oxide products via appropriate electrochemical reduction driven by renewable energy (light, heat and electricity) [3]. Therefore, these fuels can all be called regenerative fuels [4]. In this presentation, the author will analyze and discuss the feasibility of, and some preliminary findings from using molten salt electrochemistry to enable the regenerative fuels technology in the context of affordable, durable and portable high density energy storage.

References:

(1) Chen GZ, Supercapacitor and supercapattery as emerging electrochemical energy stores,
Int. Mater. Rev.
, 62 (2017) 173–202.
(2) Xia L, Yu LP, Hu D, Chen GZ, Electrolytes for electrochemical energy storage, Mater. Chem. Front.
, 1 (2017) 584–618.
(3) Ijije HV, Lawrence RC, Siambun NJ, Jeong SM, Jewell DA, Hu D, Chen GZ, Electro-deposition and re-oxidation of carbon in carbonate containing molten salts,
Faraday Discuss.
, 172 (2014) 105–116.
(4) Xia L, Chen GZ, High density electrochemical energy storage via regenerative fuels,
Chin. J. Catal.
40 (s1) (2019) 111-119.

Acknowledgement: The author thanks the financial supports from the EPSRC (EP/J000582/1 EP/F026412/1), Royal Society (Braine Mercer Feasibility Award, 2006), and Ningbo Municipal People’s Governments (3315 Plan and 2014A35001-1).

Figure 1
Effects of Ionic Liquids on the Polymerization of 3-D Print Resins
Authors: Reichert W. Matthew Matthew , Duranty Edward R. , Poole Greg 
Published: December 2020

The application of additive manufacturing in various areas of chemistry has increased dramatically in recent years including in the field of ionic liquids (ILs). It has been shown that ILs can be incorporated into the resins used in stereolithography (SLA) 3-D printing either as part of the polymer backbone or as an additive. Results have shown a change in the properties of the resulting printed polymer based on the structure of the ILs. The incorporation of the ILs into 3-D printed polymers provides the ability to customize the chemical and physical properties of a printed part. In particular, ionic liquids have been shown to act as plasticizers when incorporated into 3-D printed PMMA.
In this presentation, we will explore the effects that selected ILs have on the polymerization of the various resins used in SLA printing including the IL’s effects on the resin’s heat of polymerization. These experiments have incorporated a new technique to measure the temperature change during the polymerization process using a “TinyLev” acoustic levitator. This device provided a contact-free, container-less sample holder for a 10 µL droplet of the resin/IL mixture suspended on a standing acoustic wave. A FLIR camera was used to record the temperature change as the polymerization reaction progressed. Since the polymerization of SLA resins is typically initiated by UV light, these experiments used a 405 nm laser to initiate the polymerization reaction. A variety of ILs with different cation and anion functionalities were examined with the collected data compared to pure resin. Thermal decomposition data for these samples collected using DSC and TGA was corroborated with GPC data in order to determine the effect of the ILs on the molecular weight. This data, combined with the FLIR thermography results, provides an understanding of the role ILs have in the polymerization reaction of the resin—either as additives or as a co-polymer.

Figure 1
Solubility of Rare Earth Oxides in Fused Alkali and Alkaline Earth Halides
Authors: Volkovich Vladimir A. , Ivanov Alexander B. , Shchetinskiy Andrey V. , Mukhamadeev Andrey S. , Ryzhov Alexander A. , Afonin Yurii D. , Polovov Ilya B. , Petrov Anton I. 
Published: December 2020

Melts based on mixtures of alkali and/or alkaline earth halides are considered as prospective media for electrowinning rare earth metals as well as for pyrochemical reprocessing spent nuclear fuels. Fluoride or mixed fluoride-chloride baths can be operated at high temperatures yielding molten rare earth metals (REMs) thus simplifying separation of the metal and salt. One of the problems in using fluoride melts is possible formation of fluorine at the anode. This can be avoided by adding a rare earth oxide to the melt both as the source of REM and oxide ions. The latter will be oxidized to oxygen producing carbon mono- or dioxide at the anode. The limiting factor for feeding the electrolysis bath with REM oxides is their solubility in the halide melt.
The aim of the present study was determining the effect of temperature and melt composition on solubility of REM oxides in fused halides. The experiments were performed in CaCl2–CaF2 mixtures containing 20 or 75 mol. % CaF2; BaCl2–BaF2 mixtures containing 15 or 73 mol. % BaF2; equimolar CaF2–BaF2 mixture and NaCl–NaF eutectic mixture (34 mol. % NaF). Solubility of REM oxides was determined by the method of isothermal saturation. Time required for reaching the equilibrium between solid REM oxides and fused salts was determined in a preliminary set of experiments. To compare the behavior of 4f- and 5f-elements, solubility of uranium dioxide was also measured.
The measurements were performed at the temperatures up to 1400 oC under argon atmosphere. The lower limit of the temperature range varied from 700 to 1100 oC depending on the melting temperatures of the salt mixtures used. Oxides of yttrium, lanthanum, cerium, praseodymium, neodymium and samarium were selected for the study. To assess a possible mutual influence of rare earth elements on solubility of their oxides in fused salts the solubility of a mixture of REM oxides was determined in a separate series of experiments and concentrations of individual REMs in the melt was determined.
Solubility of REM oxides increased with increasing temperature and an example of effect of temperature on solubility of neodymium oxide in various melts is shown in Fig.
Fig. Concentration of neodymium in alkali and alkaline halide based melts saturated with Nd2O3. Melt: CaCl2–CaF2 20 mol. % (1); CaCl2–CaF2 75 mol. % (2); BaCl2–BaF2 73 mol. % (3); BaCl2–BaF2 15 mol. % (4); CaF2–BaF2 50 mol. % (5; and NaCl–NaF 34 mol. % (6).

Figure 1