bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulating the Product Distribution of the Electrochemical Reduction of CO2 on Copper at Relevant Current Densities
Authors: Parada Villarroel Walter Agustin , Sajevic Urban , Peirow Asfia Mohammad , Nikolaienko Pavlo , Mayrhofer Karl J. J. 
Published: February 2024

The electrochemical reduction of CO2 (CO2RR) has the potential to be an economically-viable method to produce platform chemicals synergistically with renewable energy sources. Copper is one of the most used electro-catalysts for this purpose, as it allows carbon-carbon bond formation, crucial for broader product distribution. Despite great achievements, controlling selectivity is yet a stepping stone between R&D and an actual industrial application. Among others, a kinetic resolution could be applied to enhance the selectivity toward targeted products, for which exploiting available and inexpensive additives or co-electrolytes such as ionic liquids is a promising direction. Herein, we present an initial systematic analysis of the effect of various tetra alkyl ammonium salts on the CO2RR products distribution with the aim on ethylene, important industrial feedstock or building block. A selected ammonium salts of different alkyl chain length and number of charges provided very concise but sufficient chemical space to overview a structure-activity relationships, including changes in the reactions’ onset potentials and limiting currents. The overall experimentation progress was intensified by the employing a developed in our lab a gas diffusion electrode (GDE) cell, coupled to a mass spectrometer. This enabled to scan the selected library of salts during CO2RR under dynamic operations with detection of transients in real-time at relatively high current densities, between 10 to 400 mA/cm2, within further quantitative validation over standard long-term steady-state experiments. These results have broad implications for effectively stirring the CO2RR selectivity towards products containing either one or two carbon atoms.
Key words: CO2, Electroreduction, Copper, Electrocatalysis, Modifiers, Real-time, GDE
Electrochemical CO2 Reduction to Formic Acid As Feedstock for Biotechnological Processes
Authors: Pangotra Dhananjai , Bohlen Barbara , Vieira Luciana , Fabarius Jonathan , Roth Arne , Sieber Volker , Pietzka Carsten , Wriedt Benjamin , Kost Hans-Joachim , Ziogas Athanassios , Löb Patrick 
Published: February 2024

Substituting fossil-based production methods with methods utilizing renewable resources is experiencing growing interest. Incorporating intermittent renewable electricity into such processes is highly desirable, especially for energy storage purposes. In this context, electrocatalytic conversion of renewable raw materials into platform chemicals is an important approach. Biogenic raw materials can be converted into platform chemicals through electrocatalysis, which can then be used in power-to-X-to-Y processes to generate a range of products. One notable example of this approach is the electrochemical conversion of CO2 into formic acid, which has numerous applications in the chemical, textile, agricultural, and pharmaceutical industries [1, 2]. Utilization of CO2-based formate as a microbial substrate is a fascinating research topic that expands the range of possible products. The work presented here focuses on optimizing a compatible interface between efficient electrochemical processs and biotechnology, by identifying key factors, including the choice of catalyst, electrolyte, electrochemical setup, and formate production rate. This study also involves testing of an electrochemical microreactor for the scalable production of formate from CO2. Our results show that formate concentrations of up to 3 mol L-1 can be achieved in a bio-compatible buffer electrolyte using an optimized electrochemical process at high current densities. Additionally, this research successfully demonstrates the biochemical utilization of electrochemically produced CO2-based formate in coupled electro-biochemical processes. The developed process is a sustainable and efficient method for producing value-added products from CO2 and renewable electric energy, contributing to bridging the gap between electrochemical and biological processes.

References

[1] B. Bohlen, D. Wastl, J. Radomski, V. Sieber, L. Vieira, Electrochemical CO2 reduction to formate on indium catalysts prepared by electrodeposition in deep eutectic solvents, Electrochemistry Communications, 110 (2020) 106597.
[2] I. Merino-Garcia, L. Tinat, J. Albo, M. Alvarez-Guerra, A. Irabien, O. Durupthy, V. Vivier, C.M. Sánchez-Sánchez, Continuous electroconversion of CO2 into formate using 2 nm tin oxide nanoparticles, Applied Catalysis B: Environmental, 297 (2021) 120447.
Electrolytic Reduction of UO2 Microspheres Synthesized Via Internal Gelation Method
Authors: Hsu Han-Hung , Breugelmans Tom , Cardinaels Thomas , Geboes Bart 
Published: February 2024

Pyroprocessing is the combination of process steps to extract and recycle actinides from fission products in spent nuclear fuels in high-temperature molten salt media. Pyroprocessing has been studied extensively over the past decades. One of the key sub-processes is the electrolytic reduction of uranium oxides. The electrolytic reduction process originated from the FFC Cambridge process, an approach for electrochemically reducing titanium dioxide into titanium metal in molten CaCl2. In the electrolytic reduction of uranium oxides, the uranium oxide feed is applied as the cathode in LiCl-Li2O molten salt electrolyte at 650°C. LiCl appears more promising than conventional CaCl2 owing to the lower melting point (878 K), and higher decomposition voltage (3.46 V at 923 K). Additionally, Li2O is expected to speed up the reduction via an additional chemical reduction pathway with the participation of Li metal, and prevents the direct dissolution of the Pt anode.
This work aims to study the morphology effect of the oxide feed on the reduction kinetics and the incorporation of impurities during the electrolytic reduction process. The electrolytic reduction of UO2 is carried out on sintered UO2 pellets, as well as various UO2 microspheres synthesized via internal gelation. The introduction of uranium oxide microspheres holds several advantages. The spheres provide a higher surface area, which is expected to improve the overall reduction efficiency of uranium oxide during electrolysis. In addition, it is easier to handle the feed during loading and unloading of the cathode basket compared to powder feeds.
The potentiostatic and galvanostatic electrolysis of UO2 is performed, and the comparison between the electrolytic reduction of UO2 pellets and microspheres is investigated. The SEM micrographs in figure 1show the morphology change of a UO2 pellet to uranium metals particles. A significant morphology change between the flat surface of the sintered UO2 feed and the reduced U particles is observed at the surface. Further characterization is performed using XRD and TGA to identify the products of the electrolytic reduction process qualitatively and quantitatively. Results show that galvanostatic electrolysis shows a better reduction efficiency compared to potentiostatic electrolysis, applied both below and above the Li formation onset potential. Overall, there is barely un-reacted UO2 visible in the XRD patterns of the reduced feed after galvanostatic electrolysis. U metal and UO are identified in the XRD patterns depending on electrolysis parameters. The presence of UO can be as an intermediate of UO2 reduction during electrolysis, which is a rare compound to be reported in literature. Overall, the reduction of microspheres does improve the overall reduction efficiency compared to the conventional pellet feeds.

Figure 1
A Numerical and Experimental Sensitivity Analysis on Electrochemical Neutral Pickling for Stainless Steel Using Secondary Current Distribution
Authors: Bossio Castro Alvaro , Gielen Ruben , Basilico Edoardo , Fransaer Jan , Baelmans Martine 
Published: February 2024

Electrochemical neutral pickling (ENP) is an extended process used in the stainless steel industry to remove the oxide surface layer formed during the annealing process. The absence of strong acids such as nitric acid results in a minimum loss of base material, improve operators working conditions, and reduces the pickling environmental impact, while keeping relatively low operation and maintenance costs. However, despite its multiple benefits, ENP may become the bottleneck for integrated annealing and pickling line, especially when processing thin austenitic and duplex steels. Fortunately, there is room for improvement as the total Faradaic efficiency of the process in typical operation is in general low (around 20 – 30 % for austenitic materials) [1]–[3], while estimations of the energy efficiency are as low as to 1 - 2 % [4].
This work provides guidelines to the design and operation of ENP cells to increase the oxide removal rate. We focus on the effect of the geometry and some operational parameters, using secondary current distribution. The simulations are validated against experimental, and a sensitivity analysis of the oxide removal rate with respect to the geometry and some key operational parameters is performed. The electrode-to-strip and the inter-electrode distances were found to have a determining effect on the total cell resistance and on its so-called geometric efficiency (relative current reaching the strip). Moreover, an optimal range for the ratio of these distances is proposed. In addition, the strip thickness and width were found to significantly affect the cell performance, especially for the thinnest gauges.

References

[1] V. I. Dunaevskii, V. T. Stepanenko, M. Y. Shnol’, and L. N. Bespal’ko, “Rate of removal of scale and subscale layer in electrolytic pickling of stainless steels in Na2SO4 solution,” Zaschita Metallov, vol. 21, no. 3, pp. 431–436, 1985.
[2] N. Ipek, B. Holm, R. Pettersson, G. Runnsjö, and M. Karlsson, “Electrolytic pickling of duplex stainless steel,” Materials and Corrosion, vol. 56, no. 8, pp. 521–532, 2005, doi: 10.1002/maco.200403858.
[3] D. Henriet, Surface treatments for stainless steel state of the art - developments and trends, no. 7210. European Comission, 1996.
[4] N. Ipek, N. Lior, F. Bark, A. Eklund, and A. Alemany, “Simple analytical model predicting some features of the electrolytic steel-pickling process,” Russian Journal of Electrochemistry, vol. 38, no. 3, pp. 238–246, 2002, doi: 10.1023/A:1014770404415.

Figure 1
(Digital Presentation) Synthesis and Characterization of Dispersed Zinc Oxide
Authors: Frolova Liliya A , Sergeyeva Olga V 
Published: February 2024

Zinc oxide has the subject of numerous studies in recent years. Nearly half of the world's annual production of zinc oxide is used as an activator to speed up vulcanization in the rubber industry. It is also widely used in pharmaceutical and cosmetic industries. It is most widely used in the chemical industry not only as a starting material, but also as a catalyst and chemisorbent. Recently, zinc oxide has been very often studied as an efficient photocatalyst in advanced oxidation processes. The cheapness and availability of zinc oxide makes it possible to use it also as a white pigment. White pigments make up more than 60% of all modern dyes. They are used for the manufacture of paints and varnishes not only white, but also other colors, as well as in the production of plastics, paper, building materials, ceramics, etc.
Obtaining nanodispersed ZnO opens up additional possibilities for controlling its chemical and physical properties. Today, to obtain nanostructured ZnO, chemical deposition, synthesis in colloidal solutions, hydrothermal synthesis, laser vapor deposition, electrochemical deposition, thermal methods, electrochemical deposition, etc. are used. Promising technologies that make it possible to obtain disperse products are physicochemical methods, including those using contact nonequilibrium plasma (CNP).
To form nanodispersed ZnO nanoparticles, we used CNP. This method is economically attractive due to the simplicity of the synthesis process (the temperature varies from room temperature to 50°C, the low cost of equipment and consumables) and the possibility of influencing the structural and morphological characteristics of NPs.
Theoretical (Pourbaix diagrams) and experimental studies (cyclic voltammograms, potentiometry, kinetic dependences, X-ray phase analysis, derivatography, electron microscopy, spectroscopy) were carried out, which made it possible to establish the possibility of obtaining zinc oxide using CNP and investigate its properties.
The results of X-ray diffraction analysis show that under these conditions, a precipitate of ZnO is formed. It was found that with an increase in rarefaction in the plasma-chemical reactor and a decrease in the interelectrode distance, an increase in the degree of conversion of zinc cations into insoluble compounds is observed. To increase the degree of conversion, the effect of organic compounds on the degree of conversion was also investigated. The addition of ethanol in the ratio 50-100 mmol/mol increases the product yield to 99.8% even in dilute solutions. Studies of color characteristics showed that the resulting precipitate has a CRC of 95%, a color purity value of 6%, and a color tone corresponding to a wavelength of 584 nm. The band gap was 3.1 eV.
High Carbon Doping of Amorphous Silicon Nanoparticles in a One-Step Gas-Phase Process for Increased Cycling Stability
Authors: Loewenich Moritz , Orthner Hans , Wiggers Hartmut 
Published: February 2024

Silicon as an anode material for Lithium-Ion-Batteries (LIB) is a promising candidate to increase overall specific energy of batteries in comparison to state-of-the-art graphite anodes. Yet the cycling stability of silicon-based electrodes is still an issue, mainly due to problems related to the swelling of silicon during lithiation to up to 300 % of its original volume. While a breakage of silicon particles can be prevented by choosing a nano-material this has the detrimental effect of increasing the surface exposed to the electrolyte, i.e. reducing coulombic efficiency. Other solutions like coatings of silicon particles and complex electrode structures are shown to increase cycling stability, but are typically connected to higher manufacturing cost.
By doping silicon nanoparticles already during production in a gas-phase one-step process, this study investigates the influence of high carbon concentrations up to 20 wt.%. This causes the silicon to stay amorphous, even at elevated temperatures. Furthermore it is shown, that the disturbance of the lattice by carbon atoms helps mitigating stress during lithiation, and can form a less reactive surface. By varying precursor concentrations during material synthesis, a range of materials were produced and analyzed physicochemically and electrochemically. For carbon values up to 15 wt.% our results show a strong increase in cycling stability of up to 80 % capacity retention after 500 cycles, and first cycle coulombic efficiencies of 80 – 90 %. Yet the increased stability is going along with a decrease in specific capacities to 1000 – 1500 mAh/g. These values were obtained for a 75 wt.% silicon, 15 % PAA, 10% C65 electrode and 1 mg/cm2, tested against lithium at 0.5 C. By linking further electrochemical results to particle properties the effects of the carbon doping are further unravelled. This material engineering offers another promising pathway to increase overall performance of silicon containing LIBs and is industrially viable, due to its inclusion in a scalable one-step material synthesis process.

Figure 1
Electrochemical Dewatering of Cellulosic Nanomaterials
Authors: Vijapur Santosh Hanamant , More Santosh R , Le Huong , Hall Timothy , Taylor E. Jennings , Inman Maria , Snyder Stephen , Nelson Kim , Handler Robert M 
Published: February 2024

Cellulose is the most abundant biomass material in nature utilized for the manufacturing of cellulosic nanomaterials that exhibit great potential in a variety of industrial applications. Although cellulosic nanomaterial is cost-effective to produce, it is not economical to ship long distances while containing significant water content (>95 wt.%). Therefore, a need has been identified by manufacturers to develop energy-efficient, dewatering or drying of cellulosic nanomaterials.
Accordingly, Faraday Technology in collaboration with GranBio USA, manufacturers of cellulosic nanomaterials, is addressing this need by developing electrochemical based dewatering system and process to dewater cellulosic nanomaterials while maintaining material properties when dried and re-dispersed. Energy-efficient (70% reduction in energy requirements compared to thermal dewatering), environmentally beneficial (51% reduction in greenhouse gas emissions), economical (31% reduction in cost/ton of dried material), and industrially viable electrochemical based dewatering approach to process up to 2 tons/year of dried nanocellulose at alpha-scale has been demonstrated. The approach is capable of achieving >50 wt.% final solids and 18 wt.% final solids, that could be rehydrated under vortex and confirmed for re-dispersibility. Material properties (structure, particle size) were maintained by the dewatered cellulosic nanomaterials. Specifically, this talk will discuss the results of these advancements.

Acknowledgements: The financial support of DOE Contract No. DE-SC0018787 is acknowledged.
Screening Electrochemical Phosphorous Recovery Conditions in Real and Synthetic Wastewater Streams
Authors: Wolfe Kody D , Heydarian Sana , Ajayi Lawrence O. , Abbas Syed Asad , Trembly Jason , Daramola Damilola 
Published: February 2024

The recovery of phosphorus (P) from wastewater via electrochemical precipitation is a promising route to improved nutrient recovery due to its ability to be coupled with current wastewater treatment processes, the viability of both small- and large-scale implementation (allowing for dispersed nutrient recovery systems), and utilization of electrons as an energy source (as opposed to chemically induced precipitation). In this talk, electrochemical P recovery from real and synthetic wastewater will be demonstrated, discussed, and contrasted. This study highlights the viability of electrochemical P recovery by considering waste stream composition, energetics of separation, and analyses of recovered products.
Specifically, both synthetic and real wastewater was tested under similar stirred batch reactor conditions with various mass transfer conditions, electrode types, and applied potentials. The reactor solution chemistry was based upon an analysis of three real waste streams and time series analyses were used to compare the transient stream conditions to conditions used in P recovery studies. Additionally, materials characterization was performed on the product of various recovery conditions and the implications of reactor conditions are discussed.
Selective Surface Feature Electropolishing of Additively Manufactured 316L Using Pulse Electrochemistry
Authors: Mirabal Alex J , Hooks Daniel E , Stull Jamie A 
Published: February 2024

Electrochemical finishing of metallic surfaces is a scalable, relatively cost-effective technique that is also versatile. One of the main detractions is that the current distribution is uneven and unspecific, often leading to a lack of shape retention and, if it goes too far, inducing corrosion. Pulsing the electrical input creates an unsteady state during electropolishing, controlling the current distribution across the part. The pulse wave prevention of general non-uniform current distribution across the entire geometry instead produces local non-uniformities in the current distribution at given surface features. Many pulse electropolishing parameters can be varied to target individual surface features, including the electrolyte, pulse height, pulse width (equally and unequally distributed), time of polishing as well as the overall waveform.
Additive manufacturing (AM) can produce unique, complex structures rapidly. The fast local melting of metal AM parts cool quickly due to the small area, causing unique microstructures, pores, and larger surface roughness compared to cast. AM microstructures change mechanical and chemical properties, such as strength and corrosion, compared to traditionally manufactured parts. Variations in build parameters and composition creates a complicated, feature dependent, corrosion response. By polishing the surface, some of the features, namely the corrosion resistance, wear, and aesthetics can be standardized and enhanced.
In this work, we explore the underlying electrochemistry that governs pulse electropolishing. We show that controlling the electrolyte with environmentally benign chemicals ultimately influences the part dimensions that can be polished, the ability to polish, and the propensity to corrode. The pulse height, pulse width (Fig. 1), and total charge passed have an impact on different surface feature removal. We will demonstrate impact of the pulse parameters on the polishing of additively manufactured stainless steel. We go beyond simple planar geometry and apply our understanding to larger scale complex geometry parts, while maintaining near-net shape and minimizing mass loss.

Figure 1
Glycerol Electrooxidation in Flow Reactors
Authors: Gaines Rachel Naomi , Sibal Adam , Griebler James John , Gaddam Raghuram , Harris Lauren C , Kleimenhagen Beth Ann , Keshireddy Ashrith , Gewirth Andrew A. , Rodriguez Lopez Joaquin , Rogers Simon A , Stillwell Ashlynn S , Kenis Paul 
Published: February 2024

Transitioning away from fossil-fuel-based chemical manufacturing is critical in advancing towards a carbon-neutral society. Chemical manufacturing processes that can be driven by renewable energy and use renewable feeds or waste products from other processes are of particular interest. This talk focuses on utilization of glycerol, a byproduct of biodiesel production and other processes, as a platform chemical for electro-organic synthesis of a number of value-added intermediates.
Oxidation of glycerol can result in ten or more different products. Processes are needed to synthesize specific products of interest selectively. Based on market size and value, the four most promising oxidation products of glycerol are lactic acid, glycolic acid, oxalic acid, and dihydroxyacetone. Electrochemical reduction and oxidation processes can, in principle, be directed to produce different products by tuning reactor and reaction conditions such as catalyst identity, electrolyte/analyte concentration, flow/stir rates, electrolyte composition, etc. While a significant body of work has studied glycerol electrooxidation (GEOR) in electrochemical cells with the goals of unraveling mechanisms and identifying better catalysts (higher rates/selectivities), transitioning some of the most promising GEOR approaches to larger scales has received limited attention.
In our work, we pursue glycerol electrooxidation in flow reactor configurations that could be scaled to industrial levels. Flow electrolysis approaches, in addition to providing a scalable chemical manufacturing platform, enhance mass transfer and kinetics while retaining the ability to tune key operational parameters that determine rates and selectivities. In this talk, we will report on two aspects: (i) Product speciation: what parameters can be used to optimize product selectivity towards key desired products (e.g., lactic acid, glycolic acid), and (ii) Feedstock composition: how to utilize raw glycerol (so-called ‘crude’ glycerol, containing varying amounts of water, NaOH, and methanol), available as a byproduct from a wide variety of plants, as the feedstock. For the former, we employ a systematic design approach that seeks to optimize the interplay between the different parameters that determine current density (conversion rate) and Faradaic efficiency (selectivity). For the latter, we explore which of the other ingredients (methanol, NaOH, water) of crude glycerol needs to be controlled or adjusted for reproducible, desired outcomes of flow glycerol electrolysis.