bluuebunny/crossref_metadata_2025_split huggingface dataset:
In-Operando Oxygen Evolution Reaction Electrocatalysis in Acidic Media
Authors: Skidmore Kayleigh , Brinkert Katharina , Walton Richard , Clayton Jasmine 
Published: September 2023

The transition from fossil fuels to renewable sources requires the utilization of green hydrogen. Electrolysis is one of the areas gaining support within both government and industry spheres, due to the possibility of producing hydrogen using renewable energy sources at a high gas purity and current density. Despite significant interest in proton-exchange membrane (PEM) electrolysis, the oxygen evolution reaction (OER) at the anode is considered one of the main bottlenecks due to the sluggish electrode kinetics and the instability of many electrocatalysts in acidic electrolytes. This is because it is a four electron reaction with a high activation barrier, and so new active electrocatalysts are needed, which in turn needs a mechanistic understanding to target new materials. In-operando studies can be used to advance the mechanistic understanding of the reaction and shed light into rate-limiting steps as well as elucidate on potential structural changes of the electrocatalysts during the reaction.
Here, we report on a modified electrochemical cell for in-operando X-ray diffraction (XRD) studies of the OER using a calcium iridium pyrochlore (Ca2-xIr2O6·H2O) electrocatalyst spray-coated onto Toray carbon paper. 1 Whilst electrochemical techniques such as chronoamperometry and cyclic voltammetry are utilized in acidic electrolyte (0.1 M H2SO4), changes to the catalyst surface and degradation rates are monitored by XRD. This provides an overall picture of phase and crystallinity changes of the iridium pyrochlore throughout the OER. X-ray absorption near edge spectroscopy (XANES), complementary to XRD, is carried out to further determine the iridium oxidation state changes during the catalytic process. The catalyst is furthermore assessed ex-situ by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) in both, pre- and post-electrochemical experiments, to examine changes to its morphology and surface composition. Appropriate cell modifications accounting for mass transport as well as gas bubble formation at the working electrode surface are developed following commercial electrolysis cell designs. This allows studying both, catalyst activity and stability, under realistic operation conditions that is currently unprecedented in the literature.
References:

Burnett, D. L. et al. Exploiting the flexibility of the pyrochlore composition for acid-resilient iridium oxide electrocatalysts in proton exchange membranes. Journal of Materials Chemistry A
9, 25114–25127 (2021).
Oxygen Reduction on Organic Mixed Ionic-Electronic Conducting Polymer Electrodes
Authors: Mefford J. Tyler , De La Fuente Duran Ana , Penn Emily E , Liang Allen Yu-Lun , Marks Adam , Chueh William C. , Salleo Alberto , Giovannitti Alexander 
Published: September 2023

Organic mixed ionic-electronic conductors (OMIECs) are a class of conjugated semiconducting polymers with tunable electronic and ionic transport properties enabled through polaron-forming ion insertion redox reactions. The energy to form these conductive polaronic states can be controlled through rational design of the polymer backbone to enable predominantly electron/cation (n-type) or hole/anion (p-type) transport. Simultaneously, electrolyte uptake into the bulk of the electrode can be controlled through incorporation of polar/non-polar sidechains. The ability to tune the energy of the redox-active states, the majority charge carrier, and the local reaction environment offers an opportunity to independently optimize activity and selectivity in electrochemical energy conversion processes with a single-phase electrode.
In this talk, I will discuss our efforts to develop OMIECs as electrocatalysts for the oxygen reduction reaction. The electronic and chemical origins of reactivity are interrogated through pH-dependent electroanalytical characterization, operando spectroscopy, charge-transport measurements, and ab initio/microkinetic simulations. The nature of the polaronic states provide a generalized framework to understand pathway selectivity towards the 2-electron H2O2 or 4-electron H2O product and serve as a design principle in developing this emerging class of metal-free electrocatalysts.
Available and Cheap Methodology for Accurate Onset Potential and Tafel Slope Determination of Earth-Abundant Water Oxidation Electrocatalysts
Authors: Seijas Da Silva Alvaro , Sanchis-Gual Roger , Otero Toribio , Coronado Eugenio , Abellán Gonzalo 
Published: September 2023

To date, a plethora of electrocatalysts for the Oxygen Evolution Reaction (OER) have been proposed. For evaluating their electrocatalytic behaviour the determination of the onset potential and Tafel slope in each studied electrolyte are key parameters.[1] Nevertheless, this evaluation becomes particularly problematic for first-transition metal catalysts as well as by the use of electroactive collectors whose redox peaks overlap the onset potential and hinder the correct determination of Tafel slope.[2] A usual solution to solve this problem is the in-situ determination of generated oxygen by mass spectrometry.[3]
However, this in-situ determination is very expensive and only available in few laboratories. To overcome these limitations, coulovoltammetric response obtained from cyclic voltammetry allow a quantitative separation in the same potential range of the charge consumed by reversible (redox peak) reactions and the charge consumed by the irreversible reaction: the oxygen release. Accordingly, by means of quantifying the irreversible charges for different anodic potential limits is possible the unambiguous determination of both, the onset potential and the Tafel slope values isolating the catalyst redox contributions. To demonstrate the use of this technique, the onset potential and the Tafel slope for three benchmark electrocatalysts based on first-transition metal: a layered double hydroxide, a Prussian blue analogue and a β-Layered hydroxide were determined.[4] This study evidence the potential of coulovoltammetry as a straightforward and powerful tool for the investigation of electrocatalytic performances.

References

[1] Fenglei Lyu, Qingfa Wang, Sung Mook Choi and Yadong Yin, Fenglei Lyu. Small,
2019, 15, 1804201.
[2] Alvaro Seijas-Da Silva, Víctor Oestreicher, Eugenio Coronado and Gonzalo Abellán. Influence of Fe-clustering in the water oxidation performance of two-dimensional layered double hydroxides. Dalton Trans., 2022, Accepted Manuscript.
[3] Dr. Kaiyue Zhu, Prof. Xuefeng Zhu and Prof. Weishen Yang, Angew.
Chem. Int. Ed.
2019, 58,1252 –1265.
[4] Roger Sanchis-Gual, Alvaro Seijas-Da Silva, Marc Coronado-Puchau, Toribio F.Otero, Gonzalo Abellán, Eugenio Coronado, Electrochimica Acta,
2021, 388, 138613.

Figure 1
Characterization of Porous Transport Electrodes in Proton Exchange Membrane Water Electrolyzers with Scanning Electron Microscopy and Micro X-ray Computed Tomography
Authors: Pylypenko Svitlana , Stelmacovich Genevieve , Khandavalli Sunilkumar , Paxson Adam 
Published: September 2023

With the move towards commercialization of proton exchange membrane water electrolyzers (PEMWE’s), the integration of the porous transport layer (PTL) and the anode catalyst layer (CL) into the porous transport electrode (PTE) is of much interest. Specifically, it is important to understand how different CL fabrication routes and ink formulations affect the performance. In addition to electrochemical characterization, a visual understanding of all components and the CL/PTL interface is needed to identify most optimum fabrication conditions.
Typically, the CL is deposited on the polymer membrane, and then integrated with PTL. Deposition of the CL onto PTL has certain advantages, but generally results in CL with variation in coverage and thickness. Depending on the catalyst loading, this can range from very thin layers on the order of several hundred nanometers, to thicker coatings on the order of tens to hundreds of microns. Typically, characterization techniques such as Scanning Electron Microscopy Electron combined with X-Ray Dispersive Spectroscopy (SEM-EDS), is used in correlation with performance testing for initial assessment of the coating heterogeneity. Top-down analysis and analysis of cross-sections are both commonly employed. Other SEM-based techniques are also used, including Focused Ion Beam (FIB) technique, which can provide information about internal structure. Micro X-ray Computed Tomography (XCT) is another powerful method for investigation of CLs and their integration with PTLs 1. Thinner CLs produced with low catalyst loadings are inherently more challenging to characterize and require multi-analytical approach.
This work investigates a series of PTEs produced using a Meyer Rod method. Fabrication parameters such as rod size, ink formulations and catalyst loadings were varied resulting in changes in the quality of the CLs. SEM-EDS and synchrotron micro-XCT (at the Advanced Photon Source (APS) on beamline 2-BM) were used to assess CL distribution, homogeneity, and thickness. This talk will discuss both benefits and limitations of using micro-XCT on these materials and compare techniques to highlight the benefit of using multiple characterization techniques for analysis.
Citations:
(1) Leonard, E.; Shum, A. D.; Danilovic, N.; Capuano, C.; Ayers, K. E.; Pant, L. M.; Weber, A. Z.; Xiao, X.; Parkinson, D. Y.; Zenyuk, I. V. Interfacial Analysis of a PEM Electrolyzer Using X-Ray Computed Tomography. Sustain. Energy Fuels
2020, 4 (2), 921–931.
Uncovering Electrochemical Cation-Storage Mechanisms in Defective Vanadium Ferrites Using Synchrotron-Quality, in-Lab X-Ray Absorption Spectroscopy
Authors: DeBlock Ryan H. , Ford Hunter O. , Chervin Christopher N. , Rolison Debra R. , Johannes Michelle D. , Long Jeffrey W. 
Published: September 2023

X-ray absorption spectroscopy (XAS) is a critical tool for investigating new materials for electrochemical energy storage, providing important information on metal oxidation state and element-specific coordination. Historically, XAS measurements had required the energy specificity and brilliance of a synchrotron facility, but recent advances in detectors and optics are bringing XAS capabilities to the laboratory setting with multiple commercial instruments available. At the Naval Research Laboratory, we use laboratory-based XAS to study 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 The structure and composition of these materials are readily varied via modifications to the epoxide-promoted sol–gel reaction of iron chloride and vanadium isopropoxide (e.g., substitution with other cations such as Al3+),2 as well as post-synthesis thermal treatments that render disordered, defective, or nanocrystalline forms of a given composition. The resulting series of VFe2Ox materials are evaluated by XAS in both ex situ and in situ configurations, including as powder-composite cathodes versus lithium metal in pouch cells with conventional nonaqueous lithium-ion electrolyte. X-ray Absorption Near-edge Spectroscopy (XANES) at the V K-edge and Fe K-edge is used to track V and Fe oxidation state, respectively, permitting the assignment of metal-centered redox across the broad potential range over which these materials are electrochemically active (2–3.4 V vs Li/Li+). Extended X-ray Absorption Fine Structure (EXAFS) analysis provides information on V- or Fe-specific coordination as a function of composition, structure, and state-of-charge. Parallel computation efforts using Density-Functional Theory offer a complementary feedback loop with experimental XANES and EXAFS to achieve a sophisticated description of these complex battery materials.
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).
(Best Student Presentation) Impact of Surface Characteristics on Interfacial Stability in Lithium Metal Batteries
Authors: Morey Madison , Ryan Emily 
Published: September 2023

A comprehensive understanding of the morphology evolution of deposited lithium (Li) is a primary challenge in the commercialization of Li-metal batteries. Li-metal batteries, which contain a Li-metal anode, have a theoretical capacity that is an order of magnitude greater than that of a Li-ion battery helping to overcome their energy storage limitations. However, while Li-metal batteries have proven to have a much larger specific capacity, they are hindered by unstable deposition at the electrode-electrolyte interface and severe dendritic growth. Interfacial stability is a complex phenomenon that is influenced by many different factors, including local current densities, overpotentials, Li+ concentrations, and transport properties. Additionally, varying surface characteristics such as surface chemistries and the physical structure of the anode can affect Li deposition and could be used to design a more stable interface. Due to the nature of the anode surface, it is difficult to observe the complex physics experimentally. Thus, computational modeling is a powerful tool for understanding the deposition of Li on the anode surface. In this work we present a computational model to comprehensively study the morphology of dendrites when exposed to varying conditions. While transport properties1, electrolyte characteristics2, separator structures3, and charging protocols4 play significant roles in Li dendrite morphology and interfacial stability, this work focuses on the impact of the anode surface itself on stability. This includes patterned anode surfaces for guided lithium deposition and varying surface chemistries such as surface energy and reaction rate. We concentrate on the types of defects that are present along the anode surface including surface roughness, points of high convexity, breaks in the SEI layer, lattice defects leading to changes in surface energy and their impact on instability. We also look at guided deposition through modifications of the anode surface.
1. J. Tan, A. M. Tartakovsky, K. Ferris, and E. M. Ryan, J Electrochem Soc, 163, A318–A327 (2016).
2. J. Tan and E. M. Ryan, J Power Sources, 323, 67–77 (2016).
3. A. Cannon and E. M. Ryan, ACS Appl Energy Mater, 4, 7848–7861 (2021).
4. T. Melsheimer, M. Morey, A. Cannon, and E. Ryan, Electrochim Acta, 433 (2022).
Enzymatic Electrochemical Immunoassay Utilizing Magnetic Beads for Detection of Preterm Birth Biomarkers
Authors: Owens Olivia E. , Buckey Grace , Cliffel David E 
Published: September 2023

The mechanisms that preclude preterm birth are largely unknown. Studying the concentration changes of known preterm birth protein biomarkers in response to infections can help elucidate these mechanisms. The development of sensors for two potential biomarkers, matrix metalloproteinase 3 (MMP-3) and interleukin-1beta (IL-1β), will aid in such studies. IL-1β is an inflammatory cytokine that assists in initiating the inflammatory response associated with birth while MMP-3 plays an essential role in degrading the fetal membrane, inducing labor. Both IL-1β and MMP-3 are known to be present during a healthy birth, but when prematurely induced, can result in preterm birth.
Magnetic bead-based competitive and sandwich assays are being developed to detect concentrations of IL-1β and MMP-3. These sensor designs utilize Horseradish peroxidase (HRP)/3,3′,5,5′-Tetramethylbenzidine (TMB) as the enzyme/substrate pair. Magnetic beads are modified with the antibody of interest and subsequently reacted with the target protein. In the competitive assays, the target protein is tagged with HRP; in the sandwich assays, a detection antibody is reacted with the target protein and subsequently tagged with HRP. When TMB is reacted with the modified beads, the HRP enzyme oxidizes TMB to TMB diimine which is then electrochemically reduced. The current generated in this process can be used to create a calibration curve with known protein concentrations versus current output. Current efforts are focused on improving sensitivity and replicability of the sensor designs. Future directions include monitoring the concentration of MMP-3 and IL-1 β before and after infection of an instrumental fetal membrane on-a-chip.
Scanning Local Redox on 10 Micron Spots on a Monolith Electrode to Quantify Multiple Analytes at 10 Attomolar Sensitivity with Dynamic Range of Seven Orders of Magnitude
Authors: Saraf Ravi , Saraf Akshat , Lim Jay Min , Prasad Abhijeet , Tevatia Rahul , Chan Alicia , Ruder Alexander 
Published: September 2023

Electrochemical transduction is arguably the most prolific and impactful method to sense chemicals and biochemicals. For example, electrochemical methods have the distinct advantage to quantitatively measure nucleic acid (NA) sequences at a limit of quantification (LOQ) of 10 attomolars and high sequence specificity. The sensitivity and dynamic range significantly surpasses optical/spectroscopic, gravimetric, and electronic transduction methods. However, electrochemical sensing cannot be easily multiplexed. Only one analyte per electrode can be measured. Furthermore, the electrode size, i.e., the sensor area, for reasonable redox current, is typically, at least 1 mm2 for small analyte concentration.
A fully automated instrument, called the Scanning Electrometer for Electrical Double-layer (SEED), will be described that addresses the abovementioned limitations. SEED, based on differential optics, quantitatively measures electrochemical process by changes in the electrical double-layer (EDL) and the surface during electrochemical process. The instrument can be operated in three modes: (a) reflectivity; (b) interferometry; (c) spectroscopy. The instrument can be toggled between the three modes without moving the sample or realigning the optics. The three modes measure the structural change at the surface, change in charge state of the EDL, and change in the molecule’s electronic structure due to the electrochemical process.
The principle will be described with following applications in material science, sensing and life science: (i) miRNA profiling at LOQ of 10 attomolar with dynamic range of seven orders of magnitude; (ii) single base mutation in NA sequence; (iii) heavy metal ion detection from ppt to ppb levels; (iv) spectroscopic measurement during redox on graphene; (v) Langmuir adsorption of ions on Au electrode; and (vi) direct measurement of potential of zero charge (PZC).

Figure 1
Quantitative Electrochemistry-Mass Spectrometry: Real-Time Detection of Volatile Products for Electrocatalysis and Batteries
Authors: Winiwarter Anna , Jensen Kim Degn , Novak Hartmann Johannes 
Published: September 2023

A major challenge both within electrocatalysis and battery research concerns the real-time (i) identification and (ii) quantification of volatile reaction products as a function of the applied electrochemical parameters and the reaction conditions. Analysis of both steadily evolving gases and of fast- and transient reaction phenomena can reveal key insights into reaction mechanisms. To this end, methods like Differential Electrochemical Mass Spectrometry (DEMS)1 and On-line Electrochemical Mass Spectrometry (OLEMS)2 have been used successfully to study reaction mechanisms to an ever-increasing degree in recent years, primarily in aqueous electrolytes. Similarly, Online Electrochemical Mass Spectrometers (OEMS)3 have been essential for the study of gas evolution in batteries.
However, to gain an in-depth understanding of these mechanisms, the ability to accurately relate the electrochemical charge transferred in the reaction to the amount of evolved product is essential. To this end, accurate calibration of MS signals is paramount. Calibration procedures available for DEMS systems are by themselves cumbersome and unreliable and full quantification is not possible for OLEMS.
Herein, we show how a simple gas-based calibration procedure using chip-based Electrochemistry-Mass Spectrometry (EC-MS) can be used for reliable, fully quantitative real-time analysis of volatile electrochemical reaction products. We validate this calibration with electrochemistry-based calibration methods described previously.4,5 The new procedure allows to extend the quantitative analysis to systems with no a priori knowledge of faradaic efficiencies. We demonstrate calibration of important gases like H2, O2 and C2H4 in aqueous and non-aqueous electrolytes and exemplify the calibration methodology’s usefulness on standard electrochemical reactions.

References

H. Baltruschat, J Am Soc Mass Spectrom, 15, 1693–1706 (2004).

A. H. Wonders, T. H. M. Housmans, V. Rosca, and M. T. M. Koper, J Appl Electrochem, 36, 1215–1221 (2006).

N. Tsiouvaras, S. Meini, I. Buchberger, and H. A. Gasteiger, J Electrochem Soc, 160, A471–A477 (2013).

D. B. Trimarco et al., Electrochim Acta, 268 (2018).

S. B. Scott, PhD thesis, Technical University of Denmark (2019).

Figure 1: a) Schematic of the MS inlet chip’s working principle. b) Uncalibrated M2 and M32 signals (dotted lines) and the same signals after calibration for H2 and O2 (full lines) in a cyclic voltammogram of PtPoly in 0.1 M HClO4 obtained at room temperature at 20 mV/s.

Figure 1