bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Chlorine on Copper Electrodissolution
Authors: Ayadathil Prajwal , Chatterjee Abhijit 
Published: February 2024

A computational study on the role of adsorbed Cl ions on copper dissolution is presented. Extensive grand canonical Monte Carlo (GCMC) calculations using reactive force-field (ReaxFF) are used to check the formation chlorine (Cl) adlayer structures on Cu (100) surface as a function of the chemical potential (µ). From experimental studies conducted by other researchers it has been observed that Cl adlattice on Cu in c(2X2) at maximum coverage. We observe that at low µ, Cl adlayer is disordered and moves to ordered c(2X2) structure at high µ. The binding energy of Cl, oxygen (O), hydroxide (OH-) and H2O on Cu at different sites is calculated and compared with Density-functional theory (DFT) values. Metal surface is often highly uneven and rough during electrodissolution process. Therefore, we also discuss the adsorption isotherm, disorder-order transformation, and preferential adsorption sites for rough surfaces. Specific anion adsorption (SAA) of Cl involves partial charge transfer to Cu substrate and these effect the type of bond and bond strength which is also briefly discussed. The electrodissolution of Cu in the presence of Cl is modelled using kinetic Monte Carlo simulation to obtain the polarization curve.
Keywords: Adsorbed chlorine, electrodissolution, grand canonical monte carlo, molecular dynamics, ReaxFF, kinetic monte carlo.
Surface Curvature Effect on Dual-Atom Site Electrocatalysis
Authors: Ivanistsev Vladislav , Cepitis Ritums , Kongi Nadezda , Rossmeisl Jan 
Published: February 2024

Oxygen, nitrogen, and carbon electrocatalysis are central in power-to-x innovations. Overpotentials of underlying processes are defined by the scaling relations between the adsorption energies of intermediates and, in turn, determine their efficiency. Our research explores the possibility of switching and tuning the scaling relations by applying metal-nitrogen-carbon (M-N-C) catalysts.
In this presentation, we introduce dual-atom site models and demonstrate the effect of surface curvature on oxygen and nitrogen electrocatalysis. Our Density Functional Theory (DFT) calculations show how curving the surface switches the scaling and significantly lowers overpotentials. For instance, we predict a bifunctional overpotential as low as 0.45 V, markedly lower than the theoretical limit of 0.74 V given by the OOH–OH scaling. [1]
Our study is among the first to investigate the surface curvature effect beyond the common scaling limitations. It will inspire the community to explore further this effect on oxygen electrocatalysis at M-N-C catalysts, as well as other challenging reactions and similarly curved materials.

Funding

V.I. and J.R. acknowledge the Danish National Research Foundation Centers of Excellence, The Center for High Entropy Alloys Catalysis (Project DNRF149), and the Independent Research Fund Denmark, grant no. 0217-00014B. V.I. receives funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska–Curie grant agreement no. 101031656. This research was also supported by the Estonian Research Council grant PSG250 and the EU through the European Regional Development Fund (TK141).

References

[1] R. Cepitis, N. Kongi, J. Rossmeisl, V. Ivaništšev, Surface Curvature Effect on Dual-Atom Site Oxygen Electrocatalysis, ACS Energy Lett. 8 (2023) 1330–1335.

Figure caption

Illustration of how reaching the optimum curvature lowers the ORR overpotential below the OOH–OH scaling-determined theoretical limit.

Figure 1
Promoting Pd-Catalyzed Conversion of CO to Formate
Authors: Wang Lei 
Published: February 2024

Electrochemical CO2 reduction offers exciting opportunities in turning the waste carbon into value-added chemicals/fuels. Among different CO2 reduction products, formate has attracted particular interest, as it shows promising near-term economic feasibility. Pd-based electrocatalysts have demonstrated excellent selectivity towards formate production, however, only within a narrow potential window of 0 V to -0.25 V vs. RHE. It has shown that Pd-based electrocatalysts suffer from the potential-dependent deactivation pathways (α-PdH to -PdH phase transition, CO poisoning, etc.) and quickly loss their activity towards formate production. Thus, it is desirable to establish new strategies to enable Pd-based CO2 reduction over a broader potential window to achieve both energy efficient and practical relevant formate production.
In this work, we discovered that ligands, i.e., polyvinylpyrrolidone, decorated Pd surface exhibits an unexpected promotion effect on CO2 electroreduction. Specifically, these decorated Pd can afford selective formate production at a much-extended potential window (beyond -0.7 V vs. RHE) with significantly improved activity (14-times enhancement at -0.4 V vs. RHE) compared to that of the pristine Pd surface. Combined results from physical/electrochemical characterizations, kinetic analysis and first principal simulations suggest that the capping ligand can effectively stabilize the Pd species with high valence state (Pdẟ+) resulted from the catalyst synthesis and pretreatments. These Pdẟ+ species are responsible for the inhibited phase transition of α-PdH to β-PdH, as well as the suppression of CO and H2 formation. Overall, our study confers a desired catalyst design principle: introducing positive charges into Pd-catalysts to enable efficient and stable CO2 to formate conversion.
Use of Surface Features with Controlled Kinetics to Verify Fits of Scanning Electrochemical Microscopy Images
Authors: Leslie Nathaniel , Mauzeroll Janine 
Published: February 2024

Scanning Electrochemical Microscopy (SECM) is a promising technique for measuring kinetics of redox reactions at surfaces. The conversion of the current map - produced by rastering an electrode over the surface - to a maps of the rate constant of reactions at the surface requires computer modelling and statistical techniques. Experimentally obtained SECM images are necessary to validate computer models that will be used to test these fitting procedures.
The largest challenge was finding or creating samples that have reactive sites of known kinetics that were sufficiently slow to be activation-limited. This was achieved by producing small precious metal electrodes embedded in an insulating surface. The exchange currents of these electrodes were characterized using cyclic voltammetry at high scan rates[1,2] so that the rate constant of the electrodes could be effectively controlled by the potential at which they were poised. SECM images of these electrodes can compared to computer simulations to verify that they produced correct results.
[1] Nicholson, R.S. Theory and Application of Cyclic Voltammetry for Measurement of Electrode Reaction Kinetics. Anal. Chem. 1965, 37, 11, 1351–1355
[2] Mirkin, M.V.; Bard, A.J. Simple Analysis of Quasi-Reversible Steady-State Voltammograms. Anal. Chem. 1992, 64, 19, 2293–2302
Monitoring Copper Ion Leaching from a Metalloporphyrin-Based Cathode for Rechargeable Magnesium Batteries
Authors: Philipp Tom , Abouzari-Lotf Ebrahim , Fichtner Maximilian , Mauzeroll Janine , Schougaard Steen Brian , Kranz Christine 
Published: February 2024

Great efforts are being undertaken to characterize the fundamental processes of solid electrolyte interphase (SEI) formation, degradation, and initial conditioning steps of battery electrode materials, including organic electrode materials.[1] Imaging techniques, such as focused ion beam / scanning electron microscopy (FIB/SEM) tomography in combination with element mapping using energy- and wavelength-dispersive X-ray spectroscopy are employed to gain insight into distribution, interconnectivity, and porosity of active materials as well as electrolyte penetration and their influence on degradation processes after longer cycling times.[2] Additionally, electrochemical impedance spectroscopy[3] and anodic stripping voltammetry[4] are used to shed light on those processes. The metalloporphyrin-based material [5,15-bis(ethynyl)-10,20-diphenylporphinato]copper(II) (CuDEPP) has been used as an interesting material for cathodes and anodes of various battery chemistries. These materials undergo initial self-conditioning by electro-polymerization for monovalent ions. With respect to multivalent ions, like magnesium, this polymerization is far less pronounced and an exchange of the copper from the CuDEPP by magnesium ions appears to be occurring.[5] Gaining insight into this trans- or demetallation process induced by parameters like the electrochemical driving force during galvanostatic cycling is a complex analytical challenge.
We report the use of Hg ultramicroelectrodes and anodic stripping voltammetry as a sensitive strategy to detect copper ion leaching from metalloporphyrin-based CuDEPP composite electrodes. We demonstrate in-situ/intermittent monitoring of copper ion release during the initial self-conditioning step of the active material while galvanostatic cycling of the battery electrode in dimethoxy ethane. This method could be used to assess the release of an ionic species from complex systems, like composite battery electrodes.
References:
[1] Peled and Menkin, J. Electrochem. Soc.
2017, 164, A1703.
[2] Philipp, Neusser, Abouzari-Lotf, Shakouri, Wilke, Fichtner, Ruben, Mundszinger, Biskupek, Kaiser, Scheitenberger, Lindén and Kranz, J. Power Sources, 2022, 522, 231002.
[3] Iurilli, Brivio and Wood, J. Power Sources, 2021, 505, 299860.
[4] Hatami, Polcari, Hossain, Ghavidel, Mauzeroll and Schougaard, J. Electrochem. Soc.
2022, 169, 040526.
[5] Abouzari-Lotf, Azmi, Li, Shakouri, Chen, Zhao-Karger, Klyatskaya, Maibach, Ruben and Fichtner, ChemSusChem.
2021, 14, 1840.
This work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm - Karlsruhe) and was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy – EXC 2154 – Project number 390874152 (POLiS Cluster of Excellence).
Electrochemical Valorization of Glycerol: Catalyst Development and Product Analysis
Authors: Angizi Shayan , Yelekli Kirici Ecem , Higgins Drew Higgins 
Published: February 2024

The growing interest in biofuels as a substitute for traditional fossil fuels has raised environmental concerns about the extensive production of their by-products. Among these by-product, Glycerol, which accounts for over 10% of the total by-products, resulted in the production of nearly 4 billion liters in 2020. (1) Glycerol is a polyol organic molecule, viscous, and water-soluble liquid that if not disposed of properly, it can have detrimental impacts on the environment, including soil and water pollution, ultimately contributing to an increase in the carbon footprint. Hence, addressing this growing concern has prompted a surge of interest in developing sustainable and economically viable techniques for converting glycerol into value-added products.
The electrochemical glycerol oxidation reaction (GOR) is a cost-effective and reliable method to enable circular economy practices by selectively producing highly value-added products such as dihydroxyacetone, glyceric acid, and glycolic acid from glycerol. However, it requires the development of active, selective, and stable electrocatalysts to steer GOR at low overpotentials. To date, catalysts based on platinum group metals (PGMs) have outperformed other GOR catalysts in terms of activity. However, in addition to the high cost of fabrication, these catalysts are susceptible to surface poisoning by glycerol intermediates, thereby impeding their commercialization due to the absence of long-term stability. (2) As a result, developing electrocatalysts based on earth-abundant element has become the focal point in GOR catalyst research.
Here in, we highlight the latest advancements in the development of low-PGM content GOR catalysts. Our discussion focuses on the strategies for understanding how the type and concentration of PGM can influence selectivity, with a particular emphasis on the significance of GOR overpotentials. We also aim to highlight the inconsistencies in GOR product analyses, specifically regarding the use of H-NMR analysis, with an ultimate goal of advancing accurate GOR product quantification.

References

Nomanbhay S, Hussein R, Ong MY. Sustainability of biodiesel production in Malaysia by production of bio-oil from crude glycerol using microwave pyrolysis: a review. Green Chemistry Letters and Reviews. 2018;11(2):135-57.

Li T, Harrington DA. An Overview of Glycerol Electrooxidation Mechanisms on Pt, Pd and Au. ChemSusChem. 2021;14(6):1472-95.
Measurement of Surface Diffusion at Electrochemical Interfaces Using in Situ Linear Optical Diffraction
Authors: Kattwinkel Lasse , Magnussen Olaf M. 
Published: February 2024

Surface diffusion processes play an important role in many reactions at electrode surfaces and are of relevance to electrocatalysis, electrodeposition, and many other areas. Such processes have therefore been extensively studied on solids under vacuum conditions with a variety of different methods. In sharp contrast, only few studies exist to measure surface diffusion in electrochemical environment due to the lack of suitable methodology. We aim on partially filling this gap by introducing the all-optical in situ LOD methodology, which allows to measure surface diffusion rates over a wide range and thus overcomes limitations of established methods that are mostly restricted to slow diffusion rates. The method is based on the generation of a periodic spatial modulation of adsorbates using two interfering laser pulses. The subsequent equilibration of this pattern and thus the diffusion rate of adsorbates is probed by the linear optical diffraction (LOD) signal from a second laser.
First proof-of-principle measurements were performed on sulfur diffusion on the Pt(111) electrode. For this purpose, the optical and electrochemical properties of this systems were investigated first, including studies of the optical reflectance change induced by chemisorbed sulfur (Sad) and investigations of the Sad oxidation mechanism. The subsequent studies of Sad surface diffusion revealed potential and coverage dependent diffusion rates which were at least an order of magnitude faster than under vacuum conditions. Supported by numerical simulations, the implications of strong adsorbate-adsorbate interaction combined with different grating modulation depths to the temporal evolution of the LOD signal were demonstrated and data accuracy and pitfalls of the method were discussed.
Kattwinkel and Magnussen, ACS Meas. Sci. Au, in press (2023), https://doi.org/10.1021/acsmeasuresciau.2c00066
Kattwinkel and Magnussen, Electrochimica Acta 434, 141297 (2022), https://doi.org/10.1016/j.electacta.2022.141297
X-Ray Photoelectron Spectroscopy Investigation of Catalyst-Ionomer Interactions for PEMFC Electrodes
Authors: Foster Jayson , Baez-Cotto Carlos , Schneider Patrick , Ahmadi Maryam , Jankovic Jasna , Zamel Nada , Mauger Scott A , Pylypenko Svitlana 
Published: February 2024

Proton exchange membrane fuel cells (PEMFCs) are an increasingly attractive clean energy technology to meet stationary and transportation energy demands without contributing to greenhouse gases. Further developments to PEMFCs are primarily focused on improving the cathode catalyst layer which uses expensive platinum catalysts to compensate for the sluggish oxygen reduction reaction and a thin film of proton conductive ionomer to aid in mass transport. It is understood that the Pt-based carbon supported catalyst may experience heterogeneity in ionomer coverage motivating further studies of catalyst layers with focus on catalyst-ionomer interface. Specifically, it is important to improve understanding of how support morphology, Pt catalyst loading, amount of ionomer, and method of catalyst layer coating affect the catalyst-ionomer interface to identify potential pathways to further to improve catalyst utilization as the technology increases in scalability.
This study focuses on investigating the catalyst-ionomer interface using x-ray photoelectron spectroscopy (XPS) as it is highly surface sensitive (top ~3-10 nm) and can capture subtle differences in the chemistry of the catalyst, ionomer, and support at the catalyst-ionomer interface. Due to the ionomer’s inherent susceptibility to x-ray induced damage, XPS analysis was conducted with a recently developed protocol to mitigate instrumental artefacts. In this work, elemental ratio quantification metrics derived from XPS are used to track surface ionomer content relative to amount of Pt nanoparticles and the amount of carbon support producing two parameters. These parameters are used to show how variations in carbon support graphitization, Pt loading, ionomer chemistry, and ionomer loading affect the catalyst-ionomer interface in unique ways. Additionally, changes to the catalyst-ionomer interface after degradation were also assessed, comparing beginning of life and end of life samples. Further, this presentation will also discuss the evolution of the catalyst-ionomer interface under humidified conditions which was assessed with in situ XPS. This talk highlights the potential of XPS to improve our understanding of relationships between surface properties, processing, performance, and durability and motivates future work in understanding catalyst layer fabrication, performance, and degradation.
The Impact of Operando Analysis in the Understanding of Oxygen Evolution Reaction Ranging from Intrinsic to Technical Scales
Authors: Spanos Ioannis , Tesch Marc Frederic , Lim Ahyoun , Schlögl Robert 
Published: February 2024

The development of state of the art and cost-effective catalyst materials for the sluggish oxygen evolution reaction (OER) is of paramount importance for realizing practical water electrolysis for green hydrogen production. Crucial for this endeavor is the determination of the OER mechanism and a better understanding of all these background processes that affect catalyst activity and stability. Thus, to further elucidate all these processes operando characterization techniques performed dynamically during OER are used as powerful tools which allow monitoring of key reaction intermediates, active sites, charge transfer and material transformation coupled processes etc. In this work we summarize our recent investigations covering noble and 3d transition metal-based OER electrocatalysts by different operando techniques and we show the importance of such techniques in the unraveling catalyst activation/deactivation mechanisms. Thus, our efforts are ranging from half-cell characterization of electrocatalyst intrinsic properties to single-cell analysis of phenomena occurring during their technical operation.
Operando techniques like eQCM, XAS, ICP-OES and single cell testing will be presented aiming to emphasize on the critical role of operando in the understanding of fundamental aspects of electrochemistry [1], like intrinsic catalyst properties (Fig. 1a), the effect of electrolyte impurities such as Fe (Fig. 1b-d) on Ni-based electrocatalysts in alkaline environment [2] as well as mechanistic phenomena taking place during catalyst activation (Fig. 1e-f) leading to the formation of the active sites for OER in acidic environment [3].

References

[1] Tesch MF, Bonke SA, Jones TE, Shaker MN, Xiao J, Skorupska K, Mom R, Melder J, Kurz P, Knop‐Gericke A, Schlögl R, Hocking RK, Simonov AN: Angew Chem Int Ed 2019, 58:3426-3432.
[2] Spanos I, Tesch MF, Yu M, Tüysüz H, Zhang J, Feng X, Müllen K, Schlögl R, Mechler AK: ACS Catal 2019, 9:8165-8170.
[3] Papakonstantinou G, Spanos I, Dam AP, Schlögl R, Sundmacher K: Phys Chem Chem Phys 2022, 24:14579-14591.

Figure 1
Comparative Study on Transport Property of Asymmetric Fluorosulfonyl(trifluoromethylsulfonyl)Amide-Based Phosphonium Ionic Liquids
Authors: Tsunashima Katsuhiko , Kikuchi Seiya , Nishikawa Kosuke , Tsuchida Yusuke , Kawaji Takatoshi , Funasako Yusuke , Yamada Hirohisa 
Published: February 2024

Room-temperature ionic liquids (RTILs), i.e. organic molten salts with melting points below ambient temperature, have been regarded as potential electrolytes for various electrochemical systems, because RTILs have unique physicochemical properties such as favorable solubility of organic and inorganic compounds, relatively high ionic conductivity, no measurable vapor pressure, high thermal stability, low flammability, etc. The quaternary phosphonium cation based RTILs have attracted attention in recent years due to their high chemical and thermal stabilities. We have proposed and synthesized a class of low viscous and highly conductive RTILs based on triethylalkylphosphonium cations in combination with typical sulfonylamide-based anions, e.g. bis(trifluoromethylsulfonyl)amide (N(SO2CF3)2
-, TFSA) and bis(fluorosulfonyl)amide (N(SO2F)2
-, FSA) anions.1,2 Our recent approaches include a design and synthesis of low-melting phosphonium based RTILs together with asymmetric fluorosulfonyl(trifluoromethylsulfonyl)amide (N(SO2F)(SO2CF3)-, FTA) anion. In this work, we report the transport property and unique viscosity behavior of several FTA anion based phosphonium RTILs as shown Fig. 1.
The FTA-based phosphonium RTILs was synthesized by aqueous ion exchange reaction of the precursor quaternary phosphonium halides with lithium FTA. The crude RTILs obtained were hydrophobic and purified by washing with pure water several times in order to remove residual metal and halide ions. The RTILs thus prepared were dried under high vacuum for at least 1 day. The physicochemical properties of RTILs, e.g. density, viscosity, conductivity (ac impedance method), were measured at elevated temperatures under argon atmosphere.
Several low-melting phosphonium RTILs were successfully prepared by combination with FTA anion (P2225, P2228 and P4441-FTA). All FTA-based phosphonium RTILs showed typical temperature dependent behaviors for density, viscosity and electrical conductivity. The conductivities of FTA-based phosphonium RTILs were higher and lower than those of corresponding TFSA- and FSA-based phosphonium RTILs, respectively; however, it should be noted that the viscosities of FTA-based phosphonium RTILs were the lowest in the phosphonium RTILs as depicted in Fig. 2. To our knowledge, such a unique viscosity behavior has not been previously reported in the FTA-based ammonium based RTILs. The detailed transport property and electrolytic behaviors such as the Arrhenius plots of viscosity and conductivity with VTF fitting and the Walden plots will be also discussed in comparison with both corresponding TFSA- and FSA-based RTILs.
References
1) K. Tsunashima, et al, Electrochem. Commun., 9, 2353 (2007).
2) K. Tsunashima, et al, Electrochem. Commun., 13, 178 (2011).

Figure 1