bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulse Electrodeposition in the Presence of Corrosion Reactions during the Off-Time
Authors: Roy Sudipta , Green Todd 
Published: February 2024

Pulse electrodeposition of metals and alloys offers one route to enhance or tune material properties. However, an often-neglected period during pulse plating is the off-time, which may also influence deposit properties. Traditionally it is considered a relatively unimportant, allowing, for example, relaxation of concentration gradients, desorption of additives, recrystallization and discharge of the double later capacitance. Over the past few decades, however, studies have shown that it is possible to have ‘internal current’ processes occurring in the off-time which can strongly influence the deposit properties and composition. For example, in the pulse electrodeposition of binary alloys from aqueous solutions, displacement (corrosion) reactions have been observed in the off-time that can significantly alter the alloy composition. This has also been observed in many aqueous and molten salt systems, and appears a very general phenomenon. More recently we have observed corrosion arising from a comproportionation reactions during the pulse plating of copper from a deep eutectic solvent (DES) and noted some of their effect on deposit properties.
The main purpose of this paper is to examine some of the similarities and differences in off-time corrosion caused by displacement and comproportionation processes during pulse electrodeposition. As is shown in the figure, corrosion may occur due to the presence of oxygen, or due the presence of a noble material leading to displacement reactions, as well as the presence of a stable species of differing valency in solution leading to comproportionation reactions. These differing mechanisms can produce different effects on the deposit. We will discuss how these different mechanisms can be understood and the influence on the deposit and their characteristics.

Figure 1
Effect of Pulsed Currents on Oxygen and Carbon Contents of Trivalent Chromium Based Deposits
Authors: Rodriguez Julymar , Lallemand Severine , Gigandet Marie-Pierre , Marcelet Martin , Legrand Benjamin , Tardelli Joffrey , Hihn Jean-Yves 
Published: February 2024

Hexavalent chromium salts have been identified as toxic for both humans and the environment by Health authorities, which led the authorities to take measures such as the implementation of strict rules, such as the REACH regulation. While some applications may be substituted by other processes, the thick hard chromium plating used for its functional properties in friction and wear lacks of alternatives. Among them, trivalent chromium salts have been extensively studied [1], but this kind of electrolytes presents typical difficulties, leading to more fragile coatings with through-cracks, and a typical increase of hardness up to very high values after annealing. This change in the chromium coating behavior is often attributed to a significant increase in carbon and oxygen contents [2].
If temperature as well as current density have shown a great influence on both carbon and oxygen, their effects are reversed, with for example a decrease in oxygen content with temperature (due to a high solubility of hydroxides) accompanied by an increase in carbon content that leads to amorphous deposits. It is however very difficult to reduce both carbon and oxygen. The present work is built on a parallel study carried-out in the IRT M2P project CRONOS 2024, which discover the possibilities to limit the pH increase at the interface by inserting long-time toff during electrodeposition [3].
Various parameters (ton times, toff times, peak current density) have been scanned for chromium deposition on a copper tip (to make the oxygen and carbon analysis easier). It has been showed that a possible control of oxygen and carbon is possible, leading to very low values and changes in deposits properties (hardness, behavior after annealing, roughness ...). The best sequence was studied for various temperatures, and the combination of parameters extensively described.
Finally, 15CDV6 steel samples were coated and fully characterized.
[1] P. Benaben, « An Overview of Hard Chromium Plating Using Trivalent Chromium Solutions », Plating and Surface Finishing, p. 8, 2011.
[2] A. Baral et R. Engelken, « Modeling, Optimization, and Comparative Analysis of Trivalent Chromium Electrodeposition from Aqueous Glycine and Formic Acid Baths », J. Electrochem. Soc., vol. 152, no 7, p. C504, 2005, doi: 10.1149/1.1933688.
[3] M. Marcelet et al., « Influence of Pulse-Current Parameters on pH Measured By Local Method », Meet. Abstr., vol. MA2019-02, no 21, p. 1046, sept. 2019, doi: 10.1149/MA2019-02/21/1046.
Electrodeposition of Metals and Their Alloys in Ionic Liquids Using Pulse Plating
Authors: Ispas Adriana , Endrikat Anna , Bund Andreas 
Published: February 2024

Pulse plating is often used to improve the morphology of deposits. One can thus electrodeposit films with finer grains and lower roughness, more compact layers by pulse plating than by direct current methods. In some cases, the throwing power and/or the adhesion of the deposits to the substrates can also be improved.
Pulse plating is widely used in industry for aqueous electrolytes, but it is not largely employed in ionic liquids (ILs). Tuning the parameters for pulse plating, such as the frequency and the duty cycle can be challenging due to the very different properties of ILs compared to most molecular solvents. Besides the pulse parameters, the effect of temperature can be rather strong, as ILs have a relatively high viscosity and thus lower conductivity. An increase in temperature will facilitate the mass transport. Further physical-chemical properties of ILs play also an important role in pulse plating applications, e. g. their double layer structure.
This paper will describe results from authors' lab on the electrodeposition of alloys in ILs. The feasibility of electrodepositing of binary alloys of Ta, Ti and Nb was investigated by varying the pulse parameters besides the types of metal salts (chloride or bromide) and ILs and temperature. Better layers in terms of morphology and purity were obtained by pulse plating techniques compared to direct current deposition.
To the best of the authors' knowledge pure titanium cannot be electrodeposited from ILs, but 9-15 wt% could be co-deposited with tantalum in 1-butyl-1-methylpyrrolidinium bis(tri-fluoromethylsulfonyl)amide.
Challenges remain with the optimization of the pulse parameters to tune the composition of the alloys and to minimize the incorporations of impurities.
The Potential of Dynamic Electrochemistry for Post-Processing of 3D-Printed Metal Parts
Authors: Hansal Selma , Hansal Wolfgang , Weiß Susanna 
Published: February 2024

Creativity has no limits with 3D-printing of metals allowing the realisation of new geometries that cannot be provided by any other production method. Nevertheless it is a long way from an innovative idea to a 3D-printing based production process. The 3D-printed metal parts leave the printer with a significant amount of support structures fixed to the part, adhering metal powder and a surface roughness that is much too high for the technical application. While mechanical post treatment methods are mostly work, time and cost intensive they also cannot provide a proper finishing on sterically hindered parts and inner surfaces.
Here chemically-electrochemically based methods, such as the Hirtisation® process, enable an integrated production process using the freedom in design of 3D-printing and additionally give an valid option for complete process automatisation that is required for standardisation and qualification of industrial serial production.
While classical electro-polishing is failing to adress most of the issues resulting from the printing process, the use of dynamic electrochemistry, in terms of using current or potential pulses to finish the surface of the metal parts, provides a powerful toolbox for this application.
This presentation will show the possibilities of dydnamic electrochemistry in terms of applying short current or potential pulses on 3D printed parts and will discuss the use of current pulses on different industrial relevant studies. A key factor for the success of such methods is a knowledge-based electrochemical tailoring of the actual current conditions at the metal surface and a deep understanding and adjustment of the material surface chemistry. Only by such an understanding of the different steps in the production chain and adjustment of these steps to each other, a constant and reproducible quality of the final products can be realised.
Characterization of Potential Dependent Fouling of Cu Electrodes during Electrochemical Hydrogenation and Hydrogenolysis of Furfural in Acid
Authors: May Andrew S. , Biddinger Elizabeth J. 
Published: February 2024

Furfural (FF) is a platform molecule derived from biomass, that can be electrochemically reduced to produce furfuryl alcohol (FA), a furanic polymer intermediate, and 2-methylfuran (MF), a fuel candidate. On Cu in acidic media, it has been shown that FA and MF are produced via parallel reactions as opposed to a series reaction. Our previous work investigated the reactions for FA and MF production electrochemically with FF concentrations between 10 and 120 mM, showing positive order with respect to FF at low concentrations and zero order rates with respect to FF at higher concentrations. This finding suggesting non-competitive Langmuir-Hinshelwood mechanisms at concentrations of FF between 10 and 120 mM in pH 0 and 1 acidic solutions. At 200 mM concentrations of FF, we have identified fouling on the Cu surface. At moderate potentials, the fouling takes the form of a polymer material, whereas at more negative reduction potentials the fouling takes the form of graphitic coking. Understanding how fouling occurs on Cu electrodes is important in achieving progress towards mitigating or reducing the impact of fouling through reactor setup and catalysts design.
In this work, conditions that promote fouling were selected so that the fouling of Cu electrodes could be studied. The conditions were chronoamperometry at -560 or -700 mV RHE, 200 mM FF, 0.5M H2SO4, 20:80 vol% acetonitrile:water, for three hours durations. The Cu electrodes were reused for 3 experiments to further promote fouling and study the impact on the electrochemical performance. We showed that after reuse at -560 mV RHE, a polymeric material formed on the Cu electrode, while when reused at -700 mV RHE the electrode was instead covered in a coke like material. FTIR spectroscopy showed that the polymer formed at -560 mV resembled poly(furfuryl alcohol) while the coking substance showed broad absorbance, expected of coke like materials. To better understand the coke material formed at -700 mV, Raman spectroscopy was used. The material resembled graphitic disorganized carbon, with a D/G band intensity ratio of 0.652.
Carbon-Based Electrode Materials for Electrocatalytic Transformations
Authors: Schröder Christian , Nolan Hugo , Brunet Cabré Marc , Pota Filippo , Mc Evoy Niall , McKelvey Kim , Colavita Paula E. 
Published: February 2024

Industrial processes for the synthesis of chemicals and fuels utilise selective hydrogenation reactions. The need for high temperatures and high pressure of H2 makes these reactions energy intensive and only viable on a large scale, requiring expensive transport of materials. Electrocatalytic hydrogenation (ECH) could potentially bypass these limitations, running at ambient conditions and generating the adsorbed hydrogen in-situ. The interest in new electrocatalyst materials increased in recent years, as ECH offers a synthetic route for fuels and value-added chemicals with a reduced carbon footprint. The development of new low-cost catalyst materials will be paramount for the integration of ECH into economic activities.
In this work we focus on heteroatom-modified carbon based electrode materials for the ECH. Carbon materials possess a list of beneficial properties for electrochemical applications: they are widely available, environmentally benign, stable at cathodic potentials and can be tailored towards specific applications. One way of tailoring is to dope the carbon with heteroatoms like nitrogen.
Nitrogen-doped carbon thin films have been synthesised using sputter deposition followed by an annealing process, to control graphitisation and nitrogen distribution of the carbon material. These model electrodes were investigated by themselves and as supports for thin nanoparticle films of MoS2 in the ECH and the hydrogen evolution reaction (HER), as the Volmer step of the HER is needed in the ECH. This allowed us to understand the influence of nitrogen moieties on reduction rates in the absence of morphological effects. The results suggest possible strategies for developing electrocatalysts for the ECH based on functional carbons.
[1] Orella, M.J.; Román-Leshkov, Y.; Brushett, F.R., Emerging opportunities for electrochemical processing to enable sustainable chemical manufacturing. Current Opinion in Chemical Engineering
2018, 20, 159–167.
[2] Behan, J. A.; Stamatin, S. N.; Hoque, M. K.; Ciapetti, G.; Zen, F.; Esteban-Tejeda, L.; Colavita, P. E., Combined Optoelectronic and Electrochemical Study of Nitrogenated Carbon Electrodes. The Journal of Physical Chemistry C
2017,
121 (12), 6596-6604.
[3] Nolan, H.; Schröder, C.; Brunet-Cabré, M.; Pota, F.; McEvoy, N.; McKelvey, K.; Perova, T. S.; Colavita, P. E., MoS2/carbon heterostructured catalysts for the hydrogen evolution reaction: N-doping modulation of substrate effects in acid and alkaline electrolytes. Carbon
2023, 202, 70-80.
Selective Anodic Conversion of Technically Relevant Lignin
Authors: Waldvogel Siegfried R 
Published: February 2024

The electrochemical conversion of less exploited biogenic side streams provides an attractive approach to valuable intermediates. Electrosynthesis represents a future technology, which is characterized by its outstanding sustainability.[1] The translation of electrosynthesis is strong dependent on the subsequent downstream processing and has to be implemented into the electrolytic screening on an early stage.[2]

A new strategy is presented to electrochemically convert lignins by ex-cell and in-cell approaches providing selectively access to monomeric species such as vanillin, 5-iodovanillin, vanillic acid and dimethoxybenzoquinone.[3-6] The key is the timely separation of oxidation and liberation event.

References:

[1] D. Pollok, S. R. Waldvogel, Chem. Sci.
2020, 11, 12375–12592.
[2] J. Seidler, J. Strugatchi, T. Gärtner, S. R. Waldvogel, MRS Energy Sustain.
2020, 7, E42.
[3] M. Zirbes, T. Graßl, R. Neuber, S. R. Waldvogel, Angew. Chem. Int. Ed.
2023, e202219217.
[4] J. Klein, S.R. Waldvogel, ChemSusChem
2023, e202202300
[5] J. Klein, R. Kupec, M. Stöckl, S. R. Waldvogel, Adv. Sustainable Syst.
2022, 2200431
[6] J. Klein, K. Alt, S. R. Waldvogel, Adv.
Sustainable Syst.
2021, 6, 2100391.
(Keynote) ALD Challenges and Opportunities in Light of Future Trends in Si-Based Nanoelectronics
Authors: Swerts Johan 
Published: February 2024

To enable CMOS transistor density scaling following Moore’s Law, device architectures transitioned in the past decade from the historical 2D planar transistor to FINFET. The next innovation touted for the 3nm node is a 3D stacked gate-all-around architecture in combination with a backside power delivery network. For further scaling, stacking nmos and pmos, the so-called complementary-FET (CFET) design, is envisaged to happen in 2030. The shrinking device dimensions of the interconnects require also new metallization schemes to tackle the RC challenge, such as Cu replacements materials in a direct metal etch integration scheme. Beyond the CFET era, one envisages the introduction of 2D-grown channel materials that will pave the way for further scaling. A broad variety of complementary deposition techniques will be needed to enable the above-mentioned novelties; among them ALD that will play a crucial role.
A similar trend towards stacking functional cells can be observed in various memories, such as the emerging memories that aim to bridge the gap between DRAM and NAND, thereby enabling fast data storage and retreival for real-time processing in connected devices at low cost. These memories are based on phase change, filamentary, magnetic, or ferroelectric mechanisms and often use multi-element materials. They have been extensively explored in 2D capacitor or transistor based devices, but for further density scaling 3D device designs are needed where a conformal deposition technique such as ALD is required. Cell scaling challenges also hold for the traditional DRAM which lead to exploring 3DDRAM integration routes. One viable pathway for scaling implies the replacement of the typical Si-channel based transistor by a deposited semiconductor oxide channel. Ultimate 3DDRAM implementation would require a conformal deposition of that channel.
In this presentation, we will discuss the opportunities and challenges of ALD in a 3D-evolving device landscape where new materials will play a key role.
In-Situ Reflectance Absorption Infra-Red Spectroscopy (RAIRS) Study on ALD of HfO2 on TiN and Pt Electrodes
Authors: Kim Jiyoung , Kim Jin-Hyun , Lee Minjong , Le Dan , Hong YeEun , Song Siun , Kim Si Joon , Choi Rino 
Published: February 2024

Ferroelectricity in hafnia fluoride analogues has been widely investigated for nonvolatile memory applications. Although ALD of HfO2 technology is enough mature for CMOS technology, hafnia-based ferroelectrics still suffer from major reliability issues such as relaxation, imprint, fatigue, and breakdown.1 These reliability characteristics are thought to be related to the interface conditions between the ferroelectric film and the electrode. Thus, many reports suggested routes to enhance reliability and ferroelectric characteristics by modifying the interface states of the metal-ferroelectric-metal (MFM) capacitors. Unfortunately, only few reports disclose direct observation on evolution of interface formation and its mechanism. Recently, it is reported that scaling down the ferroelectric hafnia-based films to a few nm range dramatically improves the MFM capacitors’ reliability where the series capacitance and surface effect dominate, making it crucial to understand the interface properties carefully.2

In this presentation, we perform In-situ characterization using reflectance absorption infrared spectroscopy (RAIRS) to monitor the surface reaction and interface formation while HfOx ALD using TDMA-Hf with various oxidation reactants, such as H2O, O3, and anhydrous H2O2. TiN and Pt bottom electrodes are investigated at 250 °C. The RAIRS results show that the initial exposure of the oxidant generates the most amount of oxidation on the TiN surface by showing Ti-O and TiN-O peaks which were not observed for the Pt substrate. Moreover, the Ti-O and TiN-O peak area increase versus the dosing time of oxidant was minimum for H2O, and O3 showed continuous peak increase even after 12 s exposure. Interestingly, for the H2O2 case, there was almost no peak increase in the Ti-O bond region like H2O, but the TiN-O and TiO-O peaks appeared after the first 3 s and saturated after 6 s exposure. Also, not only on the TiN substrate, the peak for O-O stretching was observed for the Pt substrate as well, indicating that the H2O2 generates self-limiting peroxide bonds on the surface with a minimum interface formation. This suppressed interface formation with superior film properties using H2O2 might be the reason behind the robust reliability of the H2O2-based HZO capacitor. We are going to report reliability characteristics in conjunction with interface evolution.
Acknowledements: We thank to YEST and KEIT for supporting the project through ISTD Program (No.20010806). This work is also supported by GRC-LMD program (task#3001.001) through SRC. The BRUTE hydrogen peroxide was provided by RASIRC. Ozone generator for TMEIC
References

1 J. Mohan et al., ACS AELM, 4, 4 (2022).

2 K. Toprasertpong et al., ACS AMI, 14 (2022).
(Invited) Atomic Layer Deposition on 1D Nanomaterials for Various Applications
Authors: Zazpe Raul , Sopha Hanna , Thalluri Mouli , Hromadko Ludek , Rodriguez Pereira Jhonatan , Rihova Martina , Macak Jan M. 
Published: February 2024

One-dimensional nanomaterials – materials with one dimension outside the nanoscale, further noted as 1D NMs – represent a class of very important nanomaterials with continuously increasing importance. Due to their intrinsic features, unique properties and diversity of functionalities, they count among the most widely studied materials nowadays. While considerable research efforts have been spent to synthesize various 1D NMs (e.g. nanopores, nanotubes or nanofibers), limited efforts have been devoted to surface modification and property tailoring of these materials.
However, it is their surface that comes into direct contact with various media (air, gases, liquids, solids) and influences the reactivity, stability and biocompatibility of these materials. The surface and aspect ratio (defined as their diameter to length ratio) influence the performance of these materials in various applications. Considering these facts, it is more relevant to tailor the surface of these materials and to be able to influence their properties and reactivity at the nanoscale, rather than to deal with tailoring their own bulk material composition.
The focus of this presentation is on the modification of two types of 1D nanomaterials – nanotubes and nanofibers. Numerous techniques can be utilized for this purpose, such as for example wet chemical or physical deposition techniques. However, it is only the Atomic Layer Deposition (ALD) that is capable of really uniform and homogenous coating of these 1D nanomaterials, in particular those of very high-aspect ratio.
The presentation will be mainly focused on modification of TiO2 nanotube layers and various nanofibers of different aspect ratios via ALD.
Experimental details and some very recent application examples in photocatalysis, catalysis, sensors, batteries, nanorobots, etc. [1-11] and structural characterizations of these modified materials will be discussed.

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