bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Electrochemical Cell for Operando Grazing-Incidence X-Ray Absorption Spectroscopic Studies of Low-Loaded Electrodes
Authors: Winzely Maximilian , Diercks Justus S. , Safonova Olga V. , Rüttimann Peter , Clark Adam Hugh , Leidinger Paul Maurice , Phadke Sumant , Nachtegaal Maarten , Schmidt Thomas J. , Herranz Juan 
Published: February 2024

X-ray absorption spectroscopy (XAS) is a powerful technique that can provide element specific information on the local electronic and structural properties of newly developed electrocatalysts, especially when performed under operating conditions (i.e., operando). However, the large amounts of catalyst typically needed to achieve sufficiently high spectral quality and temporal resolution can result in working electrodes of several micrometers in thickness. This can in turn lead to an inhomogeneous potential distribution across the electrode, delamination and/or incomplete utilization of the catalyst layer, severe bubble formation and accumulation due to poor mass transport properties.[1, 2] In addition, the activity and selectivity of a catalyst are often measured in a different cell geometry (e.g., using rotating disk electrodes (RDEs)), leading to uncertainties in comparison with the results inferred from spectroscopic data.[3]
To tackle these problems we have developed a new spectroelectrochemical XAS flow cell that enables spectral acquisition in fluorescence mode using an X-ray beam incidence angle of ≤ 0.1° with regards to the working electrode’s substrate plane, i.e., in a so called grazing incidence (GI) configuration (see Figure 1). In this acquisition configuration we successfully tracked the formation of palladium hydride with a time resolution of 10 seconds per spectrum while using a Pd-loading as low as 50 µgPd∙cm-2. Moreover, the careful design of the working electrode flow field allows the study of faradaic processes (e.g., O2-reduction) under mass-transport controlled conditions entailing currents comparable to those attained in RDE measurements (≤ 10 mA∙cm−2). The combination of these features with an ion-conductive membrane to separate the working- and counter-electrode compartments additionally enables the detection of gaseous products (e.g., from CO2-electroreduction) by degassing them out of the electrolyte and analyzing them in time-resolved fashion by means of mass spectrometry.[4]

References

Diklić, N., et al., Potential Pitfalls in the Operando XAS Study of Oxygen Evolution Electrocatalysts. ACS Energy Letters, 2022. 7(5): p. 1735-1740.

Diercks, J.S., et al., Spectroscopy vs. Electrochemistry: Catalyst Layer Thickness Effects on Operando/In Situ Measurements. Angew Chem Int Ed Engl, 2023: p. e202216633.

Diercks, J.S., et al., Interplay between Surface-Adsorbed CO and Bulk Pd Hydride under CO2-Electroreduction Conditions. ACS Catalysis, 2022: p. 10727-10741.

Khanipour, P., et al., Electrochemical Real-Time Mass Spectrometry (EC-RTMS): Monitoring Electrochemical Reaction Products in Real Time. Angew Chem Int Ed Engl, 2019. 58(22): p. 7273-7277

Figure 1
Operando x-Ray Absorption Spectroscopy Investigation of Secondary Metal Doping into Iron-Nitrogen-Carbon Catalysts for Oxygen Electroreduction
Authors: Luo Fang , Roy Aaron , Sougrati Moulay-Tahar , Khan Anastassiya , Cullen David A. , Wang Xingli , Primbs Mathias , Zitolo Andrea , Jaouen Frederic , Strasser Peter 
Published: February 2024

Oxygen reduction reaction (ORR) plays a key role in the development of fuel cell technology, and great efforts have been made to reduce the amount of platinum, required to speed up this sluggish reaction, or, even more desirable, to use efficient electrocatalysts based on earth-abundant metals. To date, numerous single-atom catalysts in the form of metal-doped carbon-nitrogen materials (MNC) have proved to be a promising alternative to ORR Pt-based materials. [1-3]
In this study we employed advanced spectroscopic techniques, namely Mössbauer spectroscopy and operando X-ray absorption (XAS) spectroscopy, to understand the structural and electronic factors underlying an increase in the catalytic turn over frequency (TOF) of bimetallic FeSnNC and FeCoNC catalysts, relative to the parent FeNC materials. In particular, 57Fe Mössbauer spectroscopy identified a larger ratio of D1/D2 species in both bimetallic catalysts, supporting a larger ratio of Fe(III)-Nx/Fe(II)-Nx sites. The combination of extended X-ray absorption fine structure (EXAFS) modeling, and the analysis of operando X-ray absorption near-edge spectroscopy (XANES) spectra revealed a disordered carbon structure around FeNx active sites, and variations in the iron oxidation state that can be linked to the enhanced intrinsic catalytic reactivity (TOF). This talk is therefore intended to draw attention to the potential of the XAS technique, especially when applied to in-situ/operando studies in the field of electrocatalysis.

References

F. Luo, A. Roy, L. Silvioli, D.A. Cullen, A. Zitolo, M.T. Sougrati, I.C. Oguz, T. Mineva, D. Teschner, S. Wagner, J. Wen, F. Dionigi, U.I. Kramm, J. Rossmeisl, F. Jaouen and P. Strasser. P-block single-metal-site tin/nitrogen-doped carbon fuel cell cathode catalyst for oxygen reduction reaction. Nature Materials
2020, 19, 1215-1223

A. Zitolo, N. Ranjbar, T. Mineva, J. Li, Q. Jia, S. Stamatin, G.F. Harrington, S.M. Lyth, P. Krtil, S. Mukerjee, E. Fonda, F. Jaouen. Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction. Nature Communications
2017, 8(1), 957

A. Zitolo, V. Goellner, V. Armel, M. T. Sougrati, T. Mineva, L. Stievano, E. Fonda, F. Jaouen. Identification of catalytic sites for oxygen reduction in iron and nitrogen doped graphene materials. Nature Materials
2015, 14, 937-942
Hydrous Iridium Oxide Thin Films: Revealing the Structure of a Highly Active Model Catalyst By in-Situ Ir L
3-Edge XANES and EXAFS
Authors: van der Merwe Marianne , Lee Yonyhyuk , Garcia-Diez Raul , Wibowo Enggar , Kokumai Tathiana , Efimenko Anna , Arce Mauricio D. , Jiménez Catalina Elena , Steigert Alexander , Schuck Götz , Sear Michael J. , Clark Pip , Favaro Marco , Starr David , Scheurer Christoph , Bär Marcus 
Published: February 2024

Currently, only iridium oxide shows favourable activity and stability under the harsh oxygen evolution reaction (OER) conditions for application in proton exchange membrane water electrolysis (PEM-WE) [1-3]. There is a well established inverse relationship between OER activity and stability of iridium oxide-based OER catalysts given its degree of crystallinity and hydration [4-6]. Crystalline, anhydrous iridium oxides are more stable but have diminished OER activity compared to amorphous, hydrous iridium oxides, which are more active. Different OER mechanisms have been theorized to occur on these materials, explaining their difference in performance [6]. Several spectroscopic investigations have been performed to explore the properties of such different iridium oxides, in particular to identify the chemical and electronic state of their active sites. However, a consensus regarding the active site structure and OER mechanism has yet to be reached [7-10].
Using scanning electron microscopy, x-ray photoelectron spectroscopy, and combining in-situ Ir L
3-edge x-ray absorption spectroscopy with density functional theory (DFT) calculations and ab initio thermodynamics, we have investigated in-situ electrochemically grown porous hydrous iridium oxide thin films (HIROF) as a model system to examine the chemical and electronic structure of the highly active, hydrous iridium oxide species. In-situ extended x-ray absorption fine structure(EXAFS) results show that HIROF grows preferentially in a form most often associated with the OER catalytically active site of hydrous iridium oxides. Calculations over different possible structures allowed us to identify a unique structural group with enhanced hydrogenation that best fits the EXAFS data. In-situ x-ray absorption near edge structure (XANES) results reveal a lower onset potential for the redox behaviour of HIROF compared to rutile IrO2. Based on this study, we propose a new structural model explaining the high activity and poorer stability of hydrous iridium oxides compared to crystalline IrO2.
References: [1] A. Buttler and H. Spliethoff, Renew. Sustain. Energy Rev., 2018, 82, pp. 2440-2454. [2] Schlögl, ChemSusChem, 2010, 3, pp. 209-222. [3] M. Schalenbach, J. Electrochem. Soc., 2016, 163, pp. F3197-P3208. [4] S. Cherevko, Electrochem. Commun., 2014, 48, pp. 81-85. [5] S. Cherevko, J. Electroanal. Chem., 2016(1), 773, pp 69-78. [6] S. Cherevko, J. Electroanal. Chem., 2016(2), 774, pp 102-110. [7] V. Pfeifer. Surf. Interface Anal., 2016, 48, pp. 261-273. [8] A. Minguzzi, Chem. Sci., 2014, 5, pp- 3591-3597. [9] A.H. Reksten, Phys. Chem. Chem. Phys., 2020, 22, pp. 18868-18881. [10] J.J. Veslasco-Vélez, J. Am. Chem. Soc., 2021, 143, pp. 12524-12534.
Quantitative Analysis of CO2 Evolution in an Alkaline Electrolyte Solution By Differential Electrochemical Mass Spectroscopy
Authors: Ikezawa Atsunori , Kida Juri , Shimizu Shugo , Arai Hajime 
Published: February 2024

CO2 is involved in various main and side reactions of electrochemical energy devices, such as carbon corrosion reactions and alcohol oxidation reactions. Differential electrochemical mass spectroscopy (DEMS) has been intensively applied in acidic electrolyte solutions to analyze these reactions. DEMS is the in-situ electrochemical measurement technique to analyze volatile species with the mass spectrometer (MS). However, the applications of DEMS to alkaline electrolyte solutions have been limited due to the high solubility of CO2 in alkaline solutions. While "conventional DEMS cells," where porous thin-film working electrodes are formed onto polytetrafluoroethylene (PTFE) membrane interface, can quantitatively analyze CO2 that has not dissolved into the electrolyte yet [1], the working electrode materials are limited to those that can be deposited on porous PTFE membrane as porous thin-films. Recently, Möller et al. have developed the DEMS system, which can detect CO2 from general planer electrodes coated by catalyst powders by combining a neutralizer and "dual thin-layer flow cell" [2]. However, due to the relatively low detection limit, quantitative analysis of evolved CO2 has not been accomplished. In this study, we attempt to use high surface area electrodes to enhance the MS signal of CO2 to enable quantitative analysis of evolved CO2. To suppress the in-plane reaction distribution in the flow cell, we integrated an anion exchange membrane into the cell and arranged the counter electrode opposing the working electrode [3] (Fig. 1 (a)).
CO-stripping voltammetry was performed to evaluate the CO2 detectability of the constructed DEMS system. The DEMS cell was composed of a commercial Pt/C electrode as the working electrode, a commercial Hg/HgO electrode as the reference electrode, a Pt mesh as the reference electrode, 1 mol dm–3 KOH aq as the electrolyte solution, and 1 mol dm–3 H2SO4 aq as the neutralizer. Figure 1 (b) shows the CO-stripping voltammogram and corresponding MS signal of CO2 (m/z = 44). MS signal of CO2 accompanied by the anodic CO oxidation current is clearly observed from 0.6 to 1.2 V vs. RHE. The calibration constant, which correlates the MS signal of CO2 to partial current for CO2 evolution reaction, is successfully obtained as 2.2 × 10–10, which shows that the DEMS system established in this study can quantitatively analyze CO2. Applications to the carbon corrosion reactions are also presented at the site.

References

[1] D. Bayer et al., Int. J. Hydrog. Energy, 35, 12660 (2010).
[2] S. Möller et al., Angew. Chem. Int. Ed.,
59, 1585 (2020).
[3] E. L. Clark et al., Anal. Chem.,
87, 8013 (2015).

Figure 1
The Influence of the Interfacial pH on the Electrochemical CO2 Reduction Towards Formate on Cu Electrodes
Authors: Katsoukis Georgios , Heida Hilbert C , Gutgesell Merlin , Mul Guido 
Published: February 2024

The electrochemical reduction of CO2 (CO2RR) using renewable electricity is considered a promising way to replace fossil fuels as feedstock. In aqueous media, the activity and selectivity for the CO2RR is strongly influenced by electrolyte composition at the solid-electrolyte interface. Due to competing H+ reduction, the interfacial pH is strongly affected by the applied potential which in turn determines the balance between CO2, HCO3
-, and CO3
2-. The Bicarbonate equilibrium and cation-hydroxide interactions are directly connected to the CO2RR and HER rate.[1]
To learn more about the impact of the electrolyte composition within the double layer on the CO2RR mechanism we deploy time-resolved (sub-second) FT-IR reflection-absorption spectro-electrochemistry at grazing angle using polarized light. This allows us to differentiate conversions at the electrode-electrolyte interface (i.e. CO2RR) from the diffuse double layer (i.e. pH effects). Herein, we elucidate the electrochemical CO2RR towards formate on polycrystalline Cu in aqueous bicarbonate electrolyte. We compare the rate of CH formation to the interfacial pH changes determined by the ratio between the intensity of the CO2, HCO3
-, and CO3
2- bands. We discuss how potential steps and sweeps relate to interfacial pH and CO2RR.
By applying a ‘pre’potential more positive from the open circuit potential (OCP: ca. +0.5 V vs. RHE) before stepping to -0.9 V vs. RHE, the interfacial pH decreases due to the oxidation of Cu. As a result, the rate of C-H formation is initially hindered for several seconds before setting off. Likewise, an applied ‘pre’potential more negative from the OCP results into poor C-H formation kinetics.
Reference:
[1] Liu, X.; Monteiro, M.C.O.; Koper, M. T. M. Phys. Chem. Chem. Phys. 2023, advance article.

Figure 1
(Invited) Neutrons as a Powerful Tool for Better Understanding Electrochemistry on Various Length and Time Scales
Authors: Gilles Ralph 
Published: February 2024

Today, sophisticated methods are applied to gain a deeper understanding of processes in in-situ electrochemistry. There are few ways to study electrochemically relevant processes on different length and/or time scales without affecting the processes themselves. Probes that cover a sufficient volume of the sample non-destructively and are sensitive to the important charge carriers are in great demand. For such purposes, neutrons are an ideal candidate to perform this task because they have relatively high sensitivity to the light chemical elements, can distinguish neighboring elements of the periodic table, have a large beam cross-section, and possess high penetration depth for many types of materials.
Therefore, many open questions are addressed to unique neutron techniques tailored to solve the open problems. This article gives an overview of some examples to show the advantages of using neutrons for special questions on different length and time scales [1]. For surface investigations of electrodes, the neutron depth profiling method (NDP) is suitable for characterizing the Li distribution up to the nano range [2]. Neutron diffraction is a powerful tool to better understand cylindrical cells at the atomic level, e.g. during the intercalation process [3]. Another strong field of neutrons is the monitoring of the wetting process during the electrolyte filling of prismatic hard case cells on the macroscopic length scale using the neutron imaging technique [4].
References:
[1] R. Gilles, How neutrons facilitate research into gas turbines and batteries from development to engineering applications, Journal of Surface Investigations: X-Ray, Synchrotron and Neutron Techniques, (2020), 14, Suppl. 1, S69.
[2] M. Trunk, L. Werner, R. Gernhäuser, B. Märkisch, Z. Revay, H. A. Gasteiger, M. Wetjen, R. Gilles, Materials science application of neutron depth profiling at the Prompt Gamma-ray Activation Analysis (PGAA) of Heinz Maier-Leibnitz Zentrum, Materials Characterization (2018), 146, 127.
[3] J. Wilhelm, S. Seidlmayer, S. Erhard, M. Hofmann, R. Gilles, A. Jossen, In situ neutron diffraction study of lithium gradients in graphite anodes during discharge and relaxation, Journal of the Electrochemical Society (2018), 165(9), A1846.
[4] F.J. Günter, J. Keilhofer, C. Rauch, S. Rössler, M. Schulz, W. Braunwarth, R. Gilles, R. Daub,G. Reinhart, Influence of pressure and temperature on the electrolyte filling of lithium-ion cells: Experiment, model, method, Journal of Power Sources (2022), 517, 230668.
Designing a Novel Setup for High-Throughput Investigations of Electrochemical Reactions in Real Time
Authors: Cuomo Angelina , Nikolaienko Pavlo , Mayrhofer Karl J. J. 
Published: February 2024

With the great interest in new electrochemical processes, fast screening of various reaction parameters is highly desirable. For this purpose, differential electrochemical mass spectrometry (DEMS) and membrane-inlet mass spectrometry (MIMS) have been established to enable real-time monitoring of volatile compounds. However, the analysis of non-volatile compounds is commonly limited by the temporal resolution of traditional quantification methods such as NMR, GC-MS, or LC-MS. While ambient ionization mass spectrometry (AIMS) generally enables time-resolved monitoring of non-volatile compounds, electrolyte salts can lead to ionization suppression. The latter can decrease the sensitivity of product detection and the reliability of quantitative data. Therefore, a suitable reaction setup and thorough investigations are needed when utilizing AIMS. Nonetheless, in recent efforts, an electrochemical flow cell was coupled with such a technique to provide a method for on-line monitoring of non-voltile reaction products in aqueous electrolytes. To keep up with the increasing interest in electrosynthesis in organic media, we now present a new setup that is also applicable to non-aqueous media. It pairs a novel and versatile electrochemical cell with an AIMS and DEMS for highly sensitive detection of reaction products. Moreover, various reaction parameters such as electrode material, electrolyte, and temperature can be investigated in high-throughput.
Key words: Electrocatalysis, Electrosynthesis, Real-time, On-line monitoring, High-throughput
Synchrotron Capabilities in a Laboratory Setting: In Situ X-Ray Absorption Spectroscopy of Disordered Vanadium Ferrite Electrodes for Lithium-Ion Batteries
Authors: DeBlock Ryan H. , Ford Hunter O. , Chervin Christopher N. , Rolison Debra R. , Johannes Michelle D. , Long Jeffrey W. 
Published: February 2024

X-ray absorption spectroscopy (XAS) provides important information on metal oxidation state and
element-specific coordination, but data collection has historically required the energy specificity
and brilliance of a synchrotron facility. Recent developments in detectors and optics are now
bringing XAS capabilities to the laboratory setting through multiple commercially available
instruments. At the U.S. Naval Research Laboratory, we use laboratory-based XAS to explore the
local electronic and atomic structure of a class of disordered vanadium ferrite (VFe2Ox) aerogels
that exhibit promising performance for electrochemical energy-storage applications such as
rechargeable lithium-ion batteries.1,2 These materials are synthesized by an epoxide-promoted sol–
gel reaction of iron chloride and vanadium isopropoxide, with the resulting fluid-filled gels
rendered as high surface area aerogels via supercritical-CO2 drying. During the initial sol–gel
synthesis, electroinactive metals such as aluminum, zinc, and zirconium may also be substituted
for vanadium and iron to alter the local electronic environment and corresponding electrochemical
performance of VFe2Ox. Heat treatment of as-dried VFe2Ox aerogels under either O2-containing
or inert atmosphere yields disordered or nanocrystalline variants, respectively. The resulting series
of native and substituted VFe2Ox materials are evaluated as powder-composite cathodes versus
lithium metal in coin cells with conventional nonaqueous lithium-ion electrolyte. We correlate
such critical battery-performance parameters as total specific capacity, high-rate capability, and
cycle life as a function of VFe2Ox composition and its degree of structural order/disorder, as
measured with in-situ XANES and EXAFS. In parallel with experimental observations,
calculations on VFe2Ox reveal that V incorporates into the defective spinel structure at tetrahedral
sites and that both disorder induced by vacancies and Fe/V tetrahedral occupation lowers the
overall energy and opens an electronic energy gap that establishes the redox sequence during
lithiation.
1. C. N. Chervin, J. S. Ko, B. W. Miller, L. Dudek, A. N. Mansour, M. D. Donakowski, T.
Brintlinger, P. Gogotsi, S. Chattopadhyay, T. Shibata, J. F. Parker, B. P. Hahn, D. R. Rolison,
and J. W. Long, J. Mater. Chem. A 3, 12059 (2015).
2. C. N. Chervin, R. H. DeBlock, J. F. Parker, B. M. Hudak, N. L. Skeele, J. S. Ko, D. R. Rolison,
and J. W. Long, RSC Adv. 11, 14495 (2021).
Electrochemical Behavior of Tris(2,2'-bipyridine)Iron Complex in 1-Butyl-1-Methylpyrrolidinium Bis(fluorosulfonyl)Amide Ionic Liquid in the Presence and Absence of Lithium Ion
Authors: Katayama Yasushi , Kato Shodai , Serizawa Nobuyuki 
Published: February 2024

Ionic liquids composed of bis(fluorosulfonyl)amide (FSA–) have been investigated as the promising electrolytes for rechargeable batteries because of the formation of favorable solid electrolyte interphase (SEI) for some alkali metal ions in addition to relatively low viscosity. The FSA–-based ionic liquids are also considered to be applied to redox flow batteries, which utilize the electrode reactions of soluble species on inert electrodes. However, few electrode reactions of dissolved species have been explored in the FSA–-based ionic liquids. On the other hand, ion-conductive membranes are necessary for development of redox flow batteries. An inorganic solid-state conductor, lithium ion conductive glass ceramics (LICGC, Li1+x+y
Al
x
(Ti,Ge)2-x
Si
y
P3-y
O12), is one of the possible membranes usable in ionic liquids containing Li+. In the present study, the electrochemical behavior of tris(2,2'-bipyridine)iron complexes, [Fe(bpy)3]2+, was investigated in BMPFSA (BMP = 1-butyl-1-methylpyrrolidinium) in the presence and absence of Li+.
The redox reactions of [Fe(bpy)3]3+/2+, [Fe(bpy)3]2+/+, [Fe(bpy)3]+/0, and [Fe(bpy)3]0/– were observed by cyclic voltammetry in the absence of Li+. However, these reactions were affected by the SEI formation at a negative potential region in the presence of Li+. The donor number of BMPFSA was estimated from the formal potential of [Fe(bpy)3]3+/2+. The diffusion coefficients of [Fe(bpy)3]3+ and [Fe(bpy)3]2+ were determined by chronoamperometry. The standard rate constant for [Fe(bpy)3]3+/2+ was evaluated by electrochemical impedance spectroscopy. The relationship between these kinetic parameters and physical properties was discussed.