bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulse and Pulse/Reverse Techniques for Electrodeposition of Rhenium and Refractory Metals
Authors: Hooks Daniel E , McBride Michael , Brown Nathan , Clark Courtney L , Dervishi Enkeleda 
Published: February 2024

Refractory metals possess unique properties including high melting points, high hardness at room temperature, chemical resistance, and high density. Electrodeposition of refractory metals is of interest as a scalable approach to apply uniform coatings to enable a wide range of applications in aerospace, nuclear, catalysis, biomedical fields. This talk will focus on pulse electrochemical variables to enable methods to electrodeposit high quality metallic rhenium (Re).
Re has traditionally been difficult to deposit from aqueous solutions due to the over potential for hydrogen evolution and complex electrochemical reactions. Electrodeposition of rhenium usually occurs from the perrhenate ion (ReO4-) with an oxidation state of +7. The exact mechanism to reduce the perrhenate ion from +7 to metallic rhenium is still unknown. It is unlikely that the 7 electrons transfer in a single step, so reduction likely occurs through intermediate oxide species including ReO2, ReO3 and Re2O5. Combined with the hydrogen evolution reaction, Re coatings are generally deposited at low faradaic efficiency, are brittle, and limited in thickness (sub-micron). In our previous work, water-in-salt electrolytes and complexing additives have enabled resolution of some of the issues associated with this complexity and a range of deposit qualities, though cracking issues remain and coating quality issues still needed optimization.
Herein, we present on the effects of pulsed electrochemical approaches to eliminate cracking in the film by balancing nucleation and growth and the competing hydrogen evolution reaction. A custom high-throughput cell was developed to rapidly screen parameters and explore time-dependent evolution of the electrodeposition processes.
Surface Finishing or Shaping By Pulse/Pulse-Reverse Electrolysis
Authors: Hall Timothy , Radhakrishnan Rajeswaran , Le Houng , Moran Andrew , Garich Holly , Liu Danny , Snyder Stephen , Inman Maria , Taylor Earl Jennings 
Published: February 2024

Faraday Technology Inc. is a research, development and electrochemical engineering firm developing electrochemical innovations based has pulse/pulse reverse electrolytic principles. [1,2] With that founding basis Faraday has been able to bridge the gap between academic understanding and small-scale demonstrations to commercialization of practical components for over 32 years of operation.
This presentation will discuss a broad range of surface finishing studies including a wide range of metals, additively manufactured parts, electrochemical machining, and highly complex structures. We will highlight some of the key factors that determine the usefulness and successfulness of using pulse/pulse reverse principles to enable simple water-based HF free electrolytes to finish or shape a wide range of metal surfaces. For instances, we will discuss electropolishing of Nb superconducting cavities, additively manufactured grade 5 Ti impellers, and electrochemical machining to create complex impossible to machine shapes. Each process utilizes pulse/pulse reverse operations to overcome key challenges with boundary layer control, oxidation/reduction of the surface, and the uniformity of the finish.

References:

J. Taylor “Adventures in Pulse/Pulse Reverse Electrolytic Processes: Explorations and Applications in Surface Finishing” J. Applied Surface Finishing,
3(4), 178-189 (2008).

J. Taylor, et al., (2019; Chapter 7) “Breaking the Chemical Paradigm in Electrochemical Engineering: Case Studies and Lessons Learned from Plating to Polishing” R.C. Alkire (Volume 18). Electrochemical Engineering: The Path from Discovery to Product.Wiley-VCH.
Hydrogen Production Via Mediated Electrolysis of Biomass from Distillery Whisky Waste Streams
Authors: Price Robert , MacDonald Lewis , Li Jun , Brightman Edward 
Published: February 2024

Fuel-flexible hydrogen generation methods, such as electrochemical conversion of waste biomass, offer a route to sustainable production of hydrogen (in addition to steam or water electrolysis using renewable electricity [1]) whilst valorising feedstocks that are often overlooked. [2] In this research, the authors explore the potential of a novel, two-stage electrolysis process to convert biomass-containing solid and liquid distillery waste products into hydrogen, using a phosphomolybdic acid (H3[PMo12O40] or PMA) catalyst, at lower operating voltages (<0.95 V) than proton exchange membrane (PEM) water electrolysers (1.5 – 1.6 V). [3]
Firstly, an overview of the processes, energy usage and waste stream generation at the Isle of Raasay Distillery (Hebrides, Scotland) will be provided, before results from the characterization of whisky waste products are introduced. This provides a detailed compositional analysis of both solid (draff/spent barley) and liquid (pot ale and spent lees) wastes, as well as residual alcohol analysis of the liquid wastes, and their potential for conversion to hydrogen.
Subsequently, the concept of thermal digestion of each waste-type, using the Keggin-type polyoxometalate PMA catalyst to abstract protons and electrons from biomass, will be outlined. Finally, details of electrolysis of the PMA-biomass solutions using a PEM flow cell will be provided, including electrochemical data (AC impedance spectroscopy, linear sweep voltammetry and potentiostatic operation) in order to determine the optimal operating conditions for the process, in addition to the respective yield of hydrogen from each biomass source. Prospects for upscaling the process will also be discussed.

References

Götz, M., Lefebvre, J., Mörs, F., McDaniel Koch, A., Graf, F., Bajohr, S. Reimert, R. and Kolb, T., Renew. Energ., 85, 1371 – 1390 (2016).

Liu, W., Cui, Y., Du, X., Zhang, Z., Chao, Z. and Deng, Y., Energy Environ. Sci., 9, 467 – 472 (2016).

Oh, H., Choi, Y., Shin, C., Nguyen, T. V. T., Han, Y., Kim, H., Kim, Y. H., Lee, J-W., Jang, J-W. and Ryu, J., ACS Catal.
10, 2060 – 2068 (2020).
NAD-Regenerating Biocathode Applied to Electroenzymatic Conversion of Lignin
Authors: Mishyn Vladyslav , Hickey David , Abdellaoui Sofiene 
Published: February 2024

Non-renewable and limited fossil resources (i.e. petroleum, coal, and natural gas) have been used over the last years for the production of energy, commodity chemicals, and polymer materials. Nonetheless, the extraction and consumption of these resources leads to deleterious and irreversible environmental impacts. As a sustainable alternative, lignin, one of the major components of lignocellulosic biomass, represents the most promising renewable raw material to produce aromatic-based chemicals and high value-added products. However, the use of lignin as a source of valuable molecules similar to the petroleum-derived chemicals is hindered due to its recalcitrance and structural heterogeneity. Biological approaches have been studied to develop selective and ecofriendly pathways for lignin valorization. It has been reported that some microorganisms can cleave selectively β-ether bonds representing more than a half of lignin bonding pattern.[1] The etherolytic pathway of the soil probacterium Sphingobium paucimobilis, which involves NAD-dependent dehydrogenases and β-etherases, has been well characterized for this purpose.[2] Here we focus on the design of a bioanode combining NAD-regenerating properties and the immobilization of lignin degrading enzymatic cascade to cleave such bonds. We explored the possibility of combing in situ electrochemical regeneration of NAD+ cofactor with a surface immobilized biocatalysts on a single interface. First, we have demonstrated that the electrodes based on multiwalled carbon nanotubes modified with toluidine blue are capable to regenerate NAD+ cofactor at low potential from its reduced form. This process is essential for dehydrogenases activities. Secondly, we used cross-linked hydrogel of pyrene-modified linear poly(ethyleneimine) to entrap the enzymes on the electrode surface.[3] The obtained bioanode modified with NAD-regenerating catalyst and the multi-enzymatic cascade of Lig enzymes was tested in the presence of guaiacylglycerol-β-guaiacylether (GGE), a lignin dimer substrate with β-ether bond, to produce γ-hydroxypropiovanillone (HPV). We believe that such electrochemical systems employing the enzymatic cascade acting like a metabolic funnel with the simultaneous regeneration of the cofactor would permit to refine the heterogeneous mixture of aromatics from lignin depolymerization products into a uniform distribution of value-added compounds.
[1] Renewable Sustainable Energy Rev., 2022, 157, 112025.
[2] Catal. Sci. Technol., 2016,6, 2195-2205.
[3] Chem. Sci., 2018,9, 5172-5177.

Figure 1
Electromediated Oxidation of Hydrolysed Bacterial Cellulose
Authors: Yousefi Neptun , Wilson Benjamin , Kontturi Eero 
Published: February 2024

The state-of-the-art method to isolate cellulose nanofibres employs a 2,2,6,6-Tetramethylpiperidinyloxyl (TEMPO)/NaBr/NaClO system, where the primary alcohols on the surface of cellulose microfibrils are oxidised. However, the large consumption of hypochlorite in this system makes it problematic for industrial implementation. Previously, electrochemical oxidation with a TEMPO catalyst has been reported for the preparation of cellulose nanofibres. Here, we present a study on the electromediated oxidation of bacterial cellulose (BC), the purest form of cellulose. BC has been used in a hydrolysed form, enabling the electromediated preparation of cellulose nanocrystals (CNCs), which is generally deemed even more costly than the preparation of cellulose nanofibres.
In this work, the electromediated oxidation and cyclic voltammetry were performed in an electrochemical cell, which featured three electrodes: A Hg|Hg2SO4|K2SO4 reference electrode, a titanium net counter electrode, and a carbon foam working electrode, offering a high surface area. A static potential of 0.5 V was applied during the chronoamperometry and explored oxidation times were 3, 5, 9, 12 and 24 h.
Using a TEMPO catalyst, the electromediated oxidation was applied to hydrolysed and non-hydrolysed BC fibres in a pH 10 buffer. The C6 primary hydroxyls of BC were successfully converted to sodium carboxylate groups. By the application of the TEMPO electro-mediated oxidation to hydrolysed BC for 9 h, high carboxylate and aldehyde concentrations of 1.4 and 0.3 mmol/g, respectively, were formed in the oxidized fibre. The carboxylate and aldehyde content was determined by a conductometric titration method. Surface morphologies after oxidation were investigated, showing alteration of the microfibril morphology for BC and the production of cellulose nanocrystals for hydrolysed BC. Hence, we present an effective and environmentally friendly route, which is particularly suitable for the preparation of cellulose nanocrystals.
(Invited) Advanced Atomic Layer Deposition Cycle Schemes for Large-Area Synthesis of 2D Transition Metal Dichalcogenides
Authors: Bol Ageeth Anke 
Published: February 2024

2D materials have been the focus of intense research in the last decade due to their unique physical properties. This presentation will highlight our recent progress on the large-area synthesis of two-dimensional transition metal chalcogenides for nanoelectronics using advanced atomic layer deposition cycle schemes. First, how we can use advanced cycle schemes to deposit wafer-scale polycrystalline MoS2 thin films at very low temperatures down to 100 °C. We have identified the critical role of hydrogen during the plasma step in controlling the composition and properties of molybdenum sulfide films. By increasing the H2/H2S ratio or adding an extra hydrogen plasma step to our ALD process, we are able to deposit pure polycrystalline MoS2 films at temperatures as low as 100 °C. To the best of our knowledge, this represents the lowest temperature for crystalline MoS2 films prepared by any chemical gas-phase method.[1]
ALD-grown 2D films tend to exhibit a high density of out-of-plane 3D structures in addition to 2D horizontal layers. While the out-of-plane 3D structures are ideal for catalysis applications, the presence of such 3D structures can hinder charge transport, which hampers device applications. In this presentation I will show how we used mechanistic insight obtained by HRTEM to tune the shape and density of the 3D structures during plasma-enhanced ALD using advanced atomic layer deposition schems. The obtained morphology control was further confirmed by electrical measurements.[2]
Earlier [3] we have shown that ALD is an excellent technique to make MoxW1-xS2 alloys with precise control over the alloy composition. Here, I will focus on how (plasma-enhanced) atomic layer deposition can aid in synthesizing doped 2DTMCs with precise control over the doping concentration by using elaborate ALD dosing schemes.
[1] M. Mattinen et al., Chem. Mater. (2022), 34, 5104
[2] S. Balasubramanyam, et al. ACS Appl. Mater. Interfaces (2020), 12, 3873
[3] J. J. P. M. Schulpen et al.
2D Mater. (2022), 9, 025016
Platinum Catalysts via Fluidized Bed Atomic Layer Deposition for PEM Fuel Cells
Authors: Pescher Fiona , von Holst Miriam , Salihi Arbëri , Heizmann Philipp , Stiegeler Julian , Vierrath Severin 
Published: February 2024

One of the major challenges for viable and durable proton exchange membrane fuel cells (PEMFC) in heavy duty applications is the development of stable and high-performing catalysts. The highest mass activities and stabilities can be achieved with platinum nanoparticles supported on a porous carbon support. However, these systems still suffer from degradation processes during cell operation, such as carbon corrosion and Ostwald ripening. [1] Atomic layer deposition (ALD) is an attractive alternative to the conventional wet chemical deposition of the platinum catalyst onto the carbon, promising to counteract these problems. [2,3]
ALD is a surface coating method, which employs self-limiting half-reactions between gaseous precursor molecules and a solid substrate surface. Usually, two half-reactions separated by purging or vacuuming steps represent one ALD cycle. By performing a defined number of cyclic repetitions, thin films or nanoparticles can be grown on the substrate surface with atomic-layer precision. [4]
Typically, ALD is used to coat flat surfaces. To achieve homogeneous coatings on powders, so-called fluidized bed ALD reactors fluidize the nanoparticle-powders in a gas flow, which also contains the gaseous precursor materials. This method ensures a high utilization of the precursor molecules while providing a good mixing of the sample. Thin films and nanoparticles can be deposited in a homogeneous manner onto the powder surface and into its pores. [4]
Carbon corrosion of PEMFCs can be suppressed by applying conformal ALD coatings onto the support structure. Additionally, a porous overcoating can fixate the nanoparticles against detachment and dissolution while still leaving access to the reactive sites. [5] Applying ALD to deposit fuel cell catalysts with monodisperse and highly dispersed platinum nanoparticles can counteract Ostwald ripening. [2,6]
In this study we show platinum particles deposited via ALD, which are highly dispersed and show a monodisperse size distribution. We further show TiO2-overcoatings to protect the carbon.
Literature:
[1] J. C. Meier, Beilstein J. Nanotechnol., 2014, 5, 55-67. [2] W-J. Lee, Adv. Mater. Interfaces, 2019, 6 1901210. [3] B. J. O’Neill, ACS Catal., 2015, 5, 1804. [4] W. W. McNeary, Appl. Catal. B, 2019, 254, 587-593. [5] Q. Liu, Chem. Soc. Rev., 2022, 51, 188-236. [6] Z. Xu et al., Appl. Catal. B, 2012, 111-112, 264.
Oxygen Evolution Reaction Performance Changes with Varying Crystallinity and Thickness of Atomic Layer Deposited RuO2 Film
Authors: Lee Jaehwan , Chung Seung-min , Kim Hyungjun 
Published: February 2024

As the world's population grows and the energy consumption has increased, the use of fossil fuels is gradually increasing. The carbon dioxide emitted from burning fossil fuels is a major cause of greenhouse effect. Therefore, hydrogen is widely recommended as an energy source to alternate fossil fuels due to its high energy per mass, no production of pollutant. Among several ways to obtain hydrogen, electrolysis of water is considered the most promising method. However, the slow-rate determining step of the oxygen evolution reaction (OER) compared to hydrogen evolution reaction (HER) is a main reason for interrupting wide use of electrolysis of water in the industry. So, there have been various research for enhancing the effectiveness of water electrolysis.
The development of OER electrocatalysts is needed for promote the efficiency of OER process, noble metals-based materials has been researched due to its superior activity. Among noble metals, RuO2 has been researched as promising catalyst for oxygen evolution, and the efficiency of the catalyst varies on the preparation technique (e.g., sputtering, hydrothermal methods and sol-gel). Therefore, there have been diverse studies to enhance the RuO2 electrocatalytic effectiveness of oxygen evolution via crystallinity control, increase of electrochemically active surface area by adjusting synthesizing method of RuO2 film.
Atomic Layer Deposition (ALD) has strengths of large-area uniformity, excellent conformality, and being able to control the thickness of the film at the atomic scale. ALD is suitable technique to deposit catalysts materials conformably on 3D nano-structured complex materials, so the catalytic activity in the OER can be improved by increasing the surface-to-volume ratio. Therefore, ALD is assumed as a suitable synthesizing method for electrocatalyst. Besides, ALD allows low mass loading of catalyst material which is most needed factor in the industrial area. However, there have no enough research of ALD RuO2 for OER analyzing condition (crystallinity, thickness) for obtaining enhanced OER performance.
In this report, RuO2 film was prepared based on ALD on Carbon Fiber Paper (CFP) at different deposition temperature and it showed different crystallinity, one was amorphous, the other one was crystalline. The crystalline one showed better OER performance due to its enlarged active sites of OER. We analyzed their growth characteristics and material properties by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), XRD spectrometer (XRD). And dependence of film thickness of ALD RuO2 films was also studied. Electrocatalytic properties of ALD RuO2 on CFP was measured in three-electrode. It showed low overpotential and Tafel slope, which shows electrocatalytic performances.

Figure 1
Mechanism of Infiltration between Alumina and Polyurea for Stretchable Patterned Thin Film
Authors: Lee Jae Seok , Song Seung Hak , Choi Byoung-Ho 
Published: February 2024

Conventional display panels could be replaced by OLED displays, which are a leading and popular technology in display industry. While OLEDs are quite stretchable, they are vulnerable to oxygen and moisture, and currently, there is no proper barrier film that can protect them from these elements while also maintaining high stretchability. In this study, a horizontally patterned organic/inorganic layer that can increase the stretchability of the film while also providing the necessary protection is proposed. The final structure of the thin film will consist of two layers: a stripe-patterned organic/inorganic layer created using area-selective ALD/MLD processes, followed by an organic layer.
To achieve the research objectives, the degree of infiltration of the inorganic layer into the organic layer is crucial. In this study, the mechanism behind the generation of the interface layer between alumina and polyurea is investigated. Trimethylaluminum (TMA) and H2O were used as precursors for fabricating alumina by ALD, while 1,4-phenylene diisocyanate (PPDI) and ethylene diamine (ED) were used for fabricating polyurea by MLD. The porous structure of the polymer allows ALD precursors to spread into it. During TMA pulsing on the polymer layer, the degree of infiltration is affected by the type of chemical bond in the polymer. Previous research has shown that TMA precursors are more likely to infiltrate polymers with C=O bonds into the polymer layer. Therefore, polyurea, which contains a carbonyl functional group (-C(=O)-), is suitable for this research. While the conditions for polyurea MLD are fixed, five chamber temperature conditions for depositing alumina were selected: 30℃, 50℃, 70℃, 90℃, and 110℃. Alumina was deposited by ALD on 30nm of polyurea which was deposited on a Si wafer.
From X-ray reflectivity (XRR) data, it was observed that three main types of thin films were formed. As the temperature increased, the density and thickness of the alumina layer forming the thin film changed. To verify the change in the alumina thin film, FTIR and XPS were used to compare the peaks representing the bonds of Aluminum and Oxygen.
(Invited) Atomistic Insights into Continuous and Area-Selective ALD Processes: First-Principles Simulations of the Underpinning Surface Chemistry
Authors: Karasulu Bora 
Published: February 2024

Atomic layer deposition (ALD) is a highly advanced thin film deposition technology that has found widespread use in nanoelectronics, photovoltaics, fuel cell and recently all-solid-state battery applications. It is widely regarded as the state-of-the-art technique for producing thin films due to its exceptional conformality on high-aspect ratio structures, atomic level thickness control, and tuneable film composition. In recent years, area-selective atomic layer deposition (AS-ALD) has emerged as a promising technology for high-fidelity nano-patterning, and significant progress has been made in understanding and developing highly selective processes for various material systems. Along these lines, we have recently shown that high-throughput, low defectivity, highly selective SiO2 deposition can be achieved on various substrates by combining atmospheric-pressure spatial ALD with integrated area-deactivation using small molecule inhibitors and plasma-enhanced spatial etching [1].
ALD is a surface-controlled technique that relies on the self-limiting reactions of the precursors and co-reactants with the deposition surface in alternating cycles. The initial step in ALD nucleation on the target substrate is a key factor in the deposited film quality, and efficient precursor binding on the surface is critical. Molecular dynamics (MD) simulations and minimum-energy reaction pathway analysis based on ab initio Density Functional Theory (DFT) calculations provide invaluable insights into the surface chemistry, enabling customisation of ALD processes to boost uniformity, conformality, and area-selectivity of the resulting films.
In this talk, I will discuss how first-principles simulations can be used synergistically with experimental findings to achieve high-efficiency plasma-enhanced atomic-layer cleaning (ALC) of impurities from various ALD films and substrates, design proper chemical surface modifications that enable continuous and conformal ALD nucleation even on chemically-inert surfaces (like graphene), and unveil the particular surface chemistry governing high-fidelity area-selectivity with an atomic-level precision in ultrathin coatings [1-9]. By combining the insights gained from first-principles simulations with experimental techniques, we can push the frontiers of device manufacturing to new heights, opening up exciting possibilities for further technological advances in nanoelectronics, photovoltaics, fuel cell and energy storage applications.
[1] Advanced Materials,

Just Accepted, (DOI: 10.1002/adma.202301204); [2]Nanoscale,

2021, 13, 10092-10099; [3] Chem. Mater.
2019, 31 (4), 1250-1257.; [4] Adv. Mater. Interfaces
2018, 5 (13), 1800268.; [5] Chem. Mater.
2017, 29 (3), 921–925.; [6] ACS Nano
2017, 11 (9), 9303–9311.; [7] Sol. Energy Mater. Sol. Cells
2017, 163, 43–50.; [8] Chem. Mater.
2017, 29 (5), 2090–2100.; [9] Nanoscale
2016, 8 (47), 19829–19845.

Figure 1