bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-Assembled N, P Co-Doped 3D Porous Carbon for High-Performance Potassium-Ion Battery Anodes
Authors: Yu Jeehoon , Kim DaeKyom , Choi Byung-il , Kim Jooheon , Yoo Youngjae
Published: December 2024

The development of efficient potassium-ion batteries (PIBs) is hindered by the larger ionic radius of potassium ions, which impedes rapid diffusion kinetics and limits cycle stability in graphite electrodes. In this study, we introduce a novel amorphous carbon electrode achieved through nitrogen and phosphorus co-doping, resulting in enhanced rate performance and cycling stability. The N, P co-doped carbon electrodes, synthesized via a template-free, self-assembly method, exhibit 3D porous structures with extensive surface areas, hierarchical pore architectures, and increased interlayer spaces. The optimized electrode (N3P1) demonstrates a reversible specific capacity of 258 mAh g⁻¹ at 0.1 A g⁻¹ and excellent long-term cycling stability with 96.1% capacitance retention over 800 cycles at 0.5 A g⁻¹. Kinetic analysis reveals capacitive-driven behavior attributable to the N and P co-doping, as confirmed by ex-situ transmission electron microscopy, which shows structural stability and reversibility during charge-discharge cycles. This facile synthesis approach provides a promising route for producing heteroatom-doped carbon materials for advanced electrochemical energy storage.
(General Student Poster Award Winner, 2nd Place) 3D Impedance Analysis on Mg Dissolution and Its Application to Machine Learning
Authors: Nagaya Kohki , Hoshi Yoshinao , Yamaguchi Yuki
Published: December 2024

Magnesium is expected to be as a battery anode material because of its low standard electrode potential. However, the magnesium is actively dissolved in the electrolyte solution with hydrogen evolution [1-4], which may lead to the self-discharge of the battery. Thus, the method for the life prediction of magnesium electrode as anode material is required to develop the batteries with longer lives. In the present study, we applied the machine learning for the prediction of the Mg electrode life. The 3D impedance measurement [5] of Mg electrode was carried out to obtain the parameters attributed to the Mg dissolution. These obtained parameters were applied for the machine learning to predict the electrode life.

Electrochemical measurements were performed in a three-electrode system. The working electrode was a pure magnesium plate (3 mm × 15 mm × 15 mm). A platinum wire and a saturated KCl silver / silver chloride electrode were used as the counter electrode and the reference electrode, respectively. The 3D impedance measurements were performed in a frequency range of 100 kHz to 0.01 Hz at 5 frequencies per decade and an applied DC current of 0 A. In this case, the input current amplitude was controlled to keep the output potential amplitude below 10 mV. Further, the pH detection near the magnesium electrode using iridium oxide wire and the video observation of the magnesium electrode were performed during 3D impedance measurement. The parameters estimated by the curve-fitting of the instantaneous impedance at arbitrary time from the 3D plots of impedance using an equivalent circuit were used for machine learning.

Video observation of the magnesium electrode during the 3D impedance measurement indicated that the black region was observed and spread over entire the electrode surface due to the breakdown of the oxide film [2]. The detection of pH near the magnesium electrode confirmed that the pH was increased significantly due to the growth of black region [2]. The 3D plots of impedance demonstrated that the impedance was decreased with time. In the present study, the parameters involving the solution resistance, charge transfer resistance, and electric double-layer capacitance were estimated by curve-fitting of the instantaneous impedance at arbitrary time from the 3D plots of impedance using the equivalent circuit. These parameters including pH and dissolution area were applied for the machine learning to discussed the life prediction method of magnesium electrode.

References

[1] Hoshi et. al., J. Electrochem. Soc., 163, C303 (2016).

[2] Hoshi et. al., J. Electrochem. Soc., 165, C243 (2018).

[3] Hoshi et. al., J. Electrochem. Soc., 168, 031510 (2021).

[4] Hoshi et. al., J. Electrochem. Soc., 170, 021509 (2023).

[5] Hoshi et al., Corros. Sci., 232, 112018 (2024).
Galvanic Corrosion Behavior of CFRP/Galvannealed Steel Coupling and Corrosion Inhibition
Authors: Takimoto Toshiyuki , Nishimoto Masashi , Muto Izumi
Published: December 2024

In recent years, environmental regulations for automobiles are getting stronger every year. To comply with these regulations, there is a strong need to reduce the weight of automobiles, which will lead to improve fuel economy and increase cruising range. Carbon fiber reinforced plastics (CFRP), a lightweight and high-strength material, is attracting attention as a material for the next generation of vehicles. A multi-material car body using CFRP in combination with conventional metal materials is effective in reducing the weight of automobiles. However, galvanic corrosion occurs when different materials come into electrical contact in a corrosive environment. Therefore, Inhibition of galvanic corrosion is essential for practical use of CFRP. In this study, galvanic corrosion behavior of CFRP/galvannealed steel coupling was investigated, and galvanic corrosion inhibition technology was developed.

CFRP (3K plain weave, epoxy resin) and galvannealed steel (GA) were prepared. CFRP was used on the surface and cross-section. GA was used on the surface as received and the surface of base-steel where the plating layer was removed by polishing. Galvanic corrosion tests were measured in 0.1 M NaCl saturated with air. A scanning electron microscope equipped with an energy dispersive X-ray spectroscopy system was used to observe the surface of the specimens.
Direct Imaging of Electrochemical Palladium Hydride Formation from PdCoO2 for Highly Efficient Hydrogen Evolution Reaction
Authors: Camuti Luca , Kim Se-Ho , Podjaski Filip , Lotsch Bettin Valeska , Zhang Siyuan
Published: December 2024

Active and reliable electrocatalysts are fundamental to renewable energy technologies.[1] PdCoO2 has recently been recognized as a promising catalyst for the hydrogen evolution reaction (HER) in acidic media.[2] This study unveils the activation mechanism of PdCoO2, highlighting two key processes: the leaching of Co atoms from the structure and the formation of palladium hydride (PdHx) nanoparticles.

The former process is studied by operando measurement of Co dissolution and found to be kinetically related to the HER. Scanning electron microscopy cross-sections of PdCoO2 after prolonged HER reveal a thorough transformation towards the PdHx phase. The as-formed hydride nanoparticles were found to be stable up to anodic potentials of 0.8 V (with respect to reversible hydrogen electrode at pH = 1).

The latter, i.e. the formation of hydrides, is confirmed through secondary ion mass spectrometry and quantitatively analyzed by atom probe tomography. By employing deuterium as a proxy for hydrogen, we identified the PdDx phase and determined a D/Pd atomic ratio of 0.28.

Our findings highlight the critical role of palladium hydride formation in understanding the high performance of the HER catalyst derived from PdCoO2, offering insights into the design of more efficient electrocatalysts for renewable energy technologies.

References:

[1] B. You, Y. Sun, Acc.
Chem. Res.
2018
51, 1571-1580.

[2] F. Podjaski, D. Weber, S. Zhang, L. Diehl, R. Eger, V. Duppel, E. Alarcón-Lladó, G. Richter, F. Haase, A. Fontcuberta i Morral, C. Scheu, B. V. Lotsch, Nat Catal
2020
3, 55–63.

Figure 1
Fabrication of Scaled-up Protonic Ceramic Fuel Cell By Tape Casting and Co-Sintering Process
Authors: Chung Daehan , Bae Joongmyeon
Published: December 2024

Protonic ceramic fuel cells (PCFCs) exhibit a distinct advantage over conventional solid oxide fuel cells based on oxygen ion conduction, as they operate efficiently in the relatively low-temperature range (400-600℃) owing to lower activation energy for ion conduction. While recent research has reported numerous PCFCs demonstrating exceptional electrochemical performance, studies on large-scale implementation for commercialization remain limited. The high sintering temperature required for protonic ceramic electrolyte materials poses technical challenges such as warping, delamination, and fracture during the fabrication of large-area unit cells. In this study, we aimed to address these challenges by employing an economical tape casting process for the fabrication of anode support layers, anode functional layers, and electrolyte layers. Specifically, we increased the powder size used in the tape casting process to mitigate shrinkage rate discrepancies during the sintering process. Additionally, through a case study on the load applied to the green body during the sintering process, we improved the flatness of the unit cell. The enhanced flatness of the unit cell resulted in a theoretical open circuit voltage in the electrochemical evaluation, with a 7.3% increase in maximum power density. This enhancement is attributed to the increased actual contact area due to improved flatness, leading to a reduction in interfacial contact resistance.
Enhanced Performance and Durability of Ruddlesden-Popper Oxide Anodes Decorated with Fe Nanoparticles for Direct Ammonia-Fed Solid Oxide Fuel Cells
Authors: Ha Jungseub , Choi Junil , Maeng Junbeom , Kim Won Bae
Published: December 2024

Direct ammonia-fed solid oxide fuel cells (DA-SOFCs) efficiently convert ammonia into electricity, aligning with the necessary temperatures for thermal decomposition of ammonia. However, challenges such as nitridation of anode metal catalysts and decreased cell durability hinder further development. To address these issues, this study explores the partial substitution of Sr with Ba at the A-site of the Ruddlesden-Popper (RP) structure, enhancing the structure's mixed ionic and electronic conductivity (MIEC). This modification aims to improve ammonia's thermal decomposition and the overall electrochemical performance of SOFCs. Incorporating Ba modifies the RP crystal lattice to facilitate metal nanoparticle exsolution and increase basicity, crucial for enhancing nitrogen recombination and desorption during ammonia decomposition. This adaptation helps maintain active catalyst sites and improves durability against nitridation. The study focuses on in-situ exsolution of Fe nanoparticles (NPs) and partial Ba substitution, both of which enhance not only catalytic and electrochemical performance but also durability under operating conditions.

Advanced characterization methods, including X-ray diffraction complemented by Rietveld refinement and high-resolution electron microscopy, elucidate the lattice changes and phase transitions induced by Ba. These modifications promote the exsolution of Fe NPs, pivotal for enhancing electrochemical performance. Electrochemical assessments show that the new Fe NPs exsolved La1.2Sr0.4Ba0.4Mn0.4Fe0.6O4-
δ (R-LSBMF) anode material achieves nearly 100% ammonia decomposition conversion at 650oC and sustains this activity over time, demonstrating its durability. The in-situ reduced LSBMF mixed with GDC (Ce0.9Gd0.1O2) as a DA-SOFC anode shows a maximum power density (MPD) of 1.019 W cm-2 and significantly low ohmic resistance (0.154 Ω cm²) at 800 oC.

This research advances the understanding of elemental substitution in anode materials and underscores the potential of Ruddlesden-Popper phase perovskites for high-efficiency, durable DA-SOFCs. It also enhances the prospects for ammonia as a viable fuel for SOFCs, driving the technology toward sustainable, eco-friendly energy solutions. Therefore, the outstanding catalytic and durability features of the R-LSBMF anode material open paths for commercializing DA-SOFCs, which is essential for addressing environmental challenges.

Figure 1
Developing a Bipolar Membrane-Embedded Carbon-Gradient Reverse Electrodialysis (CG-RED)
Authors: Lee Dong Hyeon , Song Hea Jung , Choi In Soo
Published: December 2024

The salinity gradient power generation by reverse electrodialysis is a technology that generates electricity from the difference in concentration between seawater and freshwater using an ion exchange membrane that selectively moves ions. Carbon-gradient reverse electrodialysis (CG-RED) is a technology based on the reverse electrodialysis that utilizes the difference in concentration of carbonate species (HCO3
-, CO3
2-) obtained from electrolytes carbonation in the feed solution through mineral carbonates to generate electricity. However, the carbonates equilibrium is difficult to control, thus limiting the power output out of the CG-RED system. To solve these problems, this study proposes the CG-RED with a bipolar membrane (BPM) placed inside the channels of the RED system. The BPM is an ion exchange membrane composed of an anion exchange layer and a cation exchange layer. A water splitting occurs at the junction of BPM to overcome the resistance when the current density exceeds the limiting value, which drives a change in pH of the solution on both sides of BPM, called pH-swing. The changed pH affects the thermodynamic activity of the carbonate species, and the pH of the feed solution can be advantageously controlled through a pH swing using BPM. In this study, optimal concentration gradient was achieved in the CG-RED system by controlling the carbonate equilibrium through pH-swing using BPM, which led to improved open-circuit voltage and power density.
The Relationship between d-Band Center of Pt in Pt-Based Catalysts and Catalytic Activity for Methanol Oxidation in an Alkaline Aqueous Solution
Authors: Matsumura Tamaki , Fukunishi Mika , Matsumoto Futoshi
Published: December 2024

In this study, in order to examine the relationship between d-band center of platinum (Pt) in Pt-based catalysts and catalytic activity for methanol electrochemical oxidation in an alkaline aqueous solution, Pt-based nanoparticle catalysts were synthesized and then their electrocatalytic activity and d-band center of Pt in the Pt-based catalyst surfaces were analyzed with X-ray photoelectron spectroscopy. Finally, the plots of electrocatalytic activity vs. d-band center of Pt atoms on the catalyst surface were obtained. The plots exhibited a so-called volcano-type correlationship (Fig. 1), indicating that there is an optimum electronic state of Pt atoms on the catalyst surfaces for the methanol oxidation. In addition, the existence of the optimum electronic state was also confirmed from the relationship between the change in the d-band center due to the elution of the second element from the Pt-based alloy catalyst and the catalytic activity.

Fig.1 Relationship between d-band center of the Pt atoms in Pt NPs/CB and Pt-based NPs/CB and current density at -0.1 V for the methanol oxidation.

Figure 1
Electrochemically Engineered Domain: Nickel–Hydroxide/Nickel Nitride Composite for Alkaline HER Electrocatalysis
Authors: Chukwuneke Chikaodili E. , Kawashima Kenta , Li Hao , Marquez Raul A. , Son Yoon Jun , Smith Lettie A , Celio Hugo , Henkleman Graeme , Mullins Charles Buddie
Published: December 2024

Alkaline hydrogen evolution reaction (HER) is challenged by the inherent lack of readily available protons for hydrogen production. Since water is the reactant, electrocatalysts needed for Alkaline HER must have a sweet spot for water dissociation and a suitable binding energy for the intermediates. One approach to minimizing the energy requirement in the alkaline HER is by creating a water dissociation site on the catalyst's surface by utilizing site engineering strategies.

In this study, cyclic voltammetry (CV) cycles are employed for electrochemical surface oxidation of nickel nitride. The incremental CV anodization led to the formation of a nickel hydroxide-nickel nitride composite which aids the water dissociation. The CV cycles were varied from 50-500 cycles for which 50 CV cycles were found to be the optimum. At 50 CV cycles, the nickel hydroxide-nickel nitride composite enhances the electrocatalytic ability of the precursor by reducing the overpotential from 172 mV to 164 mV and 207.27 mV to 192 mV at 50 and 100 mA/cm2 respectively. The results also show that the charge transfer resistance drops from 8 to 6.5 Ω ohms and the kinetics marked by the Tafel slope also improves as marked by the decrease from 140 mV/dec to 100 mV/dec. This work shows that CV anodization can improve the kinetics of nickel-based pnictides by reconstructing the surface to favor the water dissociation reaction for alkaline HER.

Figure 1
Local Probe Measurements for Designing More Efficient Photocatalyst Systems
Authors: Stinson William D. H. , Esposito Daniel V.
Published: December 2024

Photocatalytic water splitting is one promising route to reducing the cost of H2 production to industrially relevant levels. However, these particle-based systems are currently limited in their solar-to-hydrogen efficiency, requiring further development in photoabsorber and co-catalyst materials that can achieve both high activity and selectivity. One scientific challenge to advancing development of photocatalytic particles is that conventional analytical methods used to assess the performance of particle suspensions or sheets tend to measure the average or ensemble performance of a large population of particles having a distribution of sizes and compositions while often being exposed to both optical and chemical gradients within the reaction vessel. As a result, it is very difficult to uncover the structure-property-performance relationships that can guide rational design of photocatalysts. Local measurements, such as scanning electrochemical microscopy (SECM) and Raman microscopy, provide information at smaller length scales which can aid in understanding structure-property-performance relationships of individual photocatalyst particles as well as interactions between neighboring particles. Additionally, these tools can be utilized with model systems to understand how different phenomena are coupled, as well as with the introduction of selective coatings which are common in the field. As a part of broader efforts within the EFRC Ensembles of Photosynthetic Nanoreactors (EPN), our team is also advancing the use of these local techniques to correlate multiple measurements on identical particle, location or particle systems across of network of microscopists. Here, we explore the usage of Raman and SECM on model photocatalysts within the EPN correlative microscopy network. Extension of these observations to ensemble systems based on multiple particles will additionally be discussed.
Electrochemical Detection of DNA in Agriculture Using Lamp-Based Amplification
Authors: Kupresanin Ana Miodrag , Pavlovic Zoran Miroslav , Sasic Zoric Ljiljana , Pavlovic Marija , Djisalov Mila , Knezic Teodora , Janjusevic Ljiljana , Kanas Nikola , Peric Milinko , Gadjanski Ivana
Published: December 2024

The variety and complexity of genetically modified organisms (GMOs) are increasing, which makes their detection harder than ever before. This impacts the traceability, safety, and monitoring of food. Current research indicates that GM crop technology may pose risks to human health and the environment. The aim of this study is the development of a LAMP-based GMO electrochemical detection device. LAMP amplification of P-35S, P-FMV, and T-NOS regions (three elements that are most often present in genetically modified plants as part of the transgenic construct) is done using gBlocks, synthetic dsDNA fragments that have an identical DNA sequence to that of the targeted part of a transgenic construct.

Using single-stranded DNA probes containing methylene blue as a redox probe, the electrochemical DNA sensor detects LAMP products that are complementary to the target DNA. The probes were attached to the gold electrodes functionalized by gold nanoparticles, and 2D nanomaterials (MoS2, Mxenes, and reduced graphene oxide). The electrochemical methods, such as alternating current voltammetry, square wave voltammetry, and differential pulse voltammetry were employed in testing the electrochemical detection response of the DNA probes immobilized on 2D nanomaterials.

The research has shown that the obtained DNA detection signal depends significantly on the methods (and setup parameters) used in electrochemical detection, and the nanomaterials used on electrodes. The electrochemical detection resulted in a signal decrease consequential to the conformational changes of the DNA probes upon attachment of the target DNA. The methylene blue molecules attached at the top of the DNA probes get higher resistance in the electron transfer to the electrode materials, which makes the target DNA detection quantitatively and qualitatively visible. These results are promising for the development of a device that will enable a specific, sensitive, fast, cost-effective, and precise in-field detection system for the routine detection of GMOs.

**Acknowledgments:

*This project is supported by The Science Fund of the Republic of Serbia DEVELOPMENT Program - Green program of cooperation between science and industry - LABOUR project (grant agreement No. 6710), and The Ministry of Science, Technological Development and Innovation of the Republic of Serbia (451-03-66/2024-03/200358).

*This work is supported through the ANTARES project that has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement SGA-CSA. No. 739570 under FPA No. 664387. https://doi.org/10.3030/739570

Figure 1
Development of a Magnetic Bead-Based Electrochemical Sandwich Assay to Investigate Inflammatory Cytokines in an Instrumented Fetal Membrane on-a-Chip
Authors: Richards Hannah A. , Owens Olivia E. , Martin Jacklyn E. , Cliffel David E.
Published: December 2024

The instrumented fetal membrane on-a-chip (IFMOC) is a 3D microfluidic device that mimics the human fetal membranes and functions as a physiologically relevant model to investigate bacterial infections and the preterm premature rupture of the fetal membranes (PPROM) in-vitro. The magnetic bead-based electrochemical sandwich assay (MBESA) serves as an alternative to traditional enzyme-linked immunosorbent assays (ELISAs) to quantify inflammatory cytokines elevated during preterm birth (PTB), such as interleukin-1β (IL-1β). In this work, a MBESA is developed to detect IL-1β levels present within IFMOC cell cultures infected with lipopolysaccharides (LPS) and Group B Streptococcus (GBS). We present the design and application of the MBESA, highlighting the high sensitivity of an electrochemical technique in a biological platform. We discuss the fabrication and implementation of the IFMOC with the MBESA in reproductive research. The electrochemical assay was able to reproducibly detect IL-1β levels up to 600 pg/mL in RPMI 1640 with 10% FBS media. The MBESA is a promising technique to detect multiple inflammatory cytokines present in infected fetal membrane organ on-a-chip cultures. Future work includes optimizing the electrochemical performance of the MBESA, examining the inflammatory cytokine TNF-α to further elucidate PPROM mechanisms, and subsequently investigating therapeutic methods to prevent the onset of PTB.

Figure 1
Cell Culture Device with a Porous Membrane Electrode for in Situ Electrochemical Measurement of Glucose Uptake and Extracellular pH
Authors: Utagawa Yoshinobu , Ino Kosuke , Abe Hiroya , Shiku Hitoshi
Published: December 2024

Animal testing has been widely used in drug screening. However, the metabolisms of animals are different from those of humans, and thus the failure is discovered at the clinical trial stage. Therefore, reliable tissue models using human cells are needed for drug screening. Microphysiological systems (MPSs) have recently attracted attention for constructing in vivo-like microenvironments. Porous membranes have been used in cell culture devices to fabricate tissue interfaces and functional cell spheroids. Endpoint assays are general for cell evaluation in these systems. For example, labeling of biomarkers and collecting of supernatants are required to evaluate cells.

Electrochemical measurements have been used in cell analysis because of their good properties including real-time and in-situ measurements.[1] Previously, we have reported a microfluidic device with a porous membrane electrode for in-situ measurement of nitric oxide released from vascular endothelial cells.[2] In this study, we fabricated an electrochemical device integrated with a porous membrane electrode for in-situ measurement of glucose uptake[3] and extracellular pH. In glucose uptake measurement, cancer cell spheroids were put on the porous membrane electrode, and glucose was measured by enzyme-free method. In extracellular pH measurement, cells were cultured on a polyaniline-modified porous membrane electrode, and the open circuit potential versus a Ag/AgCl reference electrode was monitored.

[1] Y. Utagawa et al., Electrochemical Science Advances, 2, 2022, e2100089.

[2] Y. Utagawa et al., Analytical Chemistry, 95, 2023, 18158-18165.

[3] Y. Utagawa et al., in preparation.
(Invited) Introduction/History of Fujishima Laboratory Research
Authors: Nagahara Larry A. , Manivannan Mani
Published: December 2024

Professor Akira Fujishima (1a) has left indelible marks on the scientific landscape through his groundbreaking discoveries and innovative contributions. Renowned for his seminal work in the field of photocatalysis, Fujishima and members/visitors of his research laboratory have revolutionized various domains, ranging from renewable energy generation to environmental remediation. His pioneering discovery, along with Professor Kenich Honda, of the photocatalytic properties of titanium dioxide led to their seminal Nature paper in 1972, demonstrating the decomposition of water (1b), now called the Honda-Fujishima effect. Fujishima and colleagues laid the foundation for a myriad of applications (1c), including self-cleaning surfaces, air and water purification systems, and solar energy conversion technologies. Throughout his illustrious career, Fujishima's insights have not only expanded our fundamental understanding of surface phenomena but have also spurred advancements with profound implications for sustainability and global well-being.

Reference:

Fujishima and K. Honda, Nature, 238, 37-38 (1972).

Figure 1
(Invited) Shooting Electron Bullets through Catalyst Pores
Authors: Petek Hrvoje
Published: December 2024

Intermolecular spaces between molecules support nonviolence correlation-bound anion states, or more colloquially superstorm states. Such states can act as electron waveguides for photoinduced donor-acceptor charge transfer, as we demonstrate by ultrafast coherent photoelectron spectroscopy. We explore the possibility of photoinduced coherent charge transfer through such waveguides and anticipate their potential role in photocatalytic chemistry.
(Invited) Semiconductor-Sensitized Thermal Cell: Difference of Photoexcitation and Thermal Excitation
Authors: Matsushita Sachiko
Published: December 2024

A new thermal energy conversion approach called a semiconductor-sensitized thermal cell (STC) was recently reported by the presenters' group.[1,2] STC was inspired by a dye-sensitized solar cell (DSSC), i.e., a photoelectrochemical solar cell. The redox reactions of photoexcited carriers in dyes generate electric power in DSSC. In STC, the redox reactions of thermally-excited carriers in semiconductors generate electric power. It has a simple structure: semiconductor-electrode, counter-electrode, and electrolyte. The power generation was terminated once the chemical equilibrium reached the set temperature. Flipping the switch, the cell moved to a different equilibrium state, restoring its power generation characteristics.

Over the past few years, STC research has progressed. The redox ability of thermally excited carriers in semiconductors has been demonstrated using FeSi2[1] and Ge.[2] The analogy of STC and DSSC has been shown by organic-perovskite-[3] and Ag2S-[4] sensitized cells since those semiconductor-sensitized cells could generate electricity from light and heat, respectively. Inductively coupled plasma (ICP) measurements showed that electric power generation was not accomplished through the elution of semiconductor electrodes.[5]

In this presentation, we will carefully explain the STC process, starting with thermally excited charge generation in semiconductors, which is unfamiliar to chemists, and introduce the academic and social implementation directions of STC.

[1] S. Matsushita, A. Tsuruoka, E. Kobayashi, T. Isobe, A. Nakajima, "Redox reactions by thermally excited charge carriers: towards sensitized thermal cells," Mater. Horiz., 4 649–656 (2017).

[2] K. Tamaki, S. Matsushita, "Counter electrode dependence of germanium-sensitized thermal cells," Jpn. J. Appl. Phys.
63 01SP22 (2024).

[3] S. Matsushita, S. Sugawara, T. Isobe, A. Nakajima, "Temperature Dependence of a Perovskite-Sensitized Solar Cell: A Sensitized “Thermal” Cell," ACS Appl. Energy Mater., 2 13-18 (2019).

[4] Y. Inagawa, T. Isobe, A. Nakajima, S. Matsushita, "Ag2S-Sensitized Thermal Cell," J. Phys. Chem. C, 123 12135-12141 (2019).

[5] S. Matsushita, T. Araki, B. Mei, S. Sugawara, Y. Inagawa, J. Nishiyama, T. Isobe, A. Nakajima, "A sensitized thermal cell recovered using heat," J. Mater. Chem. A, 7 18249-18256 (2019).
(Invited) Roles of Oxygen Vacancies in Photocatalysts for Nitrogen Reduction to Ammonia
Authors: Wu Nianqiang
Published: December 2024

Oxygen vacancies in metal oxides can significantly promote photocatalytic activity toward nitrogen reduction to ammonia. The underlying mechanism remains poorly understood. This talk will examine how the presence of oxygen vacancies in metal oxide will affect light absorption, charge separation, migration, recombination and injection. We will identify the roles of oxygen vacancies in the photosynthesis process.
(Invited) Electrocatalytic Activity and Structural Insights of Cu, Fe and N-Doped Mesoporous Carbon for the Oxygen Reduction Reaction
Authors: Kato Masaru , Asakura Hiroyuki , Yagi Ichizo
Published: December 2024

For widespread applications of polymer electrolyte fuel cells, non-PGM electrocatalysts with high oxygen reduction reaction (ORR) activity and product selectivity to H2O need to be developed. Metal, nitrogen-doped carbon (M–N–C, M = Fe, Co, Cu, etc.) electrocatalysts have been intensively studied as non-PGM based electrocatalysts in acidic media for the ORR because they show relatively high ORR activity in the non-PGM-based electrocatalysts. Recently, heterometallic doping into nitrogen-doped carbon, which is known as dual-metal atom catalysts, can show the cooperative effect on the ORR activity and product selectivity. We have also developed such heterometallic non-PGM electrocatalysts of Cu, Fe, N-doped carbon nanotubes for the ORR in acidic media, inspired by the active site of a natural ORR catalyst of cytochrome c oxidase [1]. The co-doping of Cu and Fe in carbon nanotubes improves the ORR activity and product selectivity toward H2O via four-electron transfer. However, its ORR activity is relatively low (a turnover frequency of 0.40 e– site–1 s–1 at +0.80 V vs. RHE) and the structure of the active site remains unclear.

We report the synthesis, activity and structural insight of a Cu, Fe, N-doped mesoporous carbon, (Cu,Fe)–N–mesoC, electrocatalyst for the ORR in acidic media. (Cu,Fe)–N–mesoC was prepared in pyrolysis from the composite of an iron complex of a 1,12-diazatriphenylene ligand [2], a multinuclear copper complex of 1,2,4-triazole [3] and mesoporous carbon. (Cu,Fe)–N–mesoC shows a turnover frequency of 1.35 e– site–1 s–1 at +0.80 V vs. RHE and a low hydrogen peroxide yield (< 5%). X-ray absorption and emission spectroscopy of (Cu,Fe)–N–mesoC was performed to understand the structure of the active site.

References.

[1] M. Kato, N. Fujibayashi, D. Abe, N. Matsubara, S. Yasuda, I. Yagi, ACS Catal., 11, 2356-2365 (2021).

[2] K. Matsumoto et al., Chem. Eur. J., 28, e20210345 (2022).

[3] M. Kato et al., ACS Appl. Energy Mater., 1, 2358-2364 (2018).
(Invited) Characterization of Polymers Using Electrochemical Analysis and Thermoamperometry
Authors: Kim Byung-Kwon
Published: December 2024

Research aimed at analyzing the characteristics of polymers serves not only to enhance understanding of polymers but also to improve their properties. Polymer analysis has traditionally relied on techniques such as chromatography, spectroscopy, and thermal analysis, with electrochemical analysis being less commonly utilized. This is partly due to polymers themselves often lacking electrical properties and potentially interfering with current flow by blocking electrode surfaces. However, the numerous advantages of electrochemical analysis, including rapid response, simplicity of operation, and low equipment costs, provide compelling reasons for its increased application in polymer analysis. In this presentation, I aim to introduce a method for measuring the molecular weight changes of several polymers using electrochemistry and to present a new electrochemical analysis technique called thermoamperometry, which allows observation of phase transition characteristics of polymers.
(Invited) Synthesizing Cathode Precursors Directly from Lithium Ores
Authors: Wang Shilong , Szymanski Nathan , Zeng Yan , Ceder Gerbrand
Published: December 2024

Abstract:

With the increasing demand of lithium (Li) used for energy storage, there is a need for diversified Li sources beyond brines. Among the minerals that can satisfy this need, spodumene is most often used for its high Li content and natural abundance. However, the traditional approach to process spodumene is costly and energy-intensive, requiring that the mineral be transformed from its naturally occurring α phase into the more reactive β phase at temperatures exceeding 1000 °C [1, 2]. Acid leaching is then used to extract Li, followed by neutralization to precipitate Li in the form of Li2CO3, a common precursor for the synthesis of Li-ion battery cathodes. Recently, we have developed an improved procedure to extract Li directly from α-spodumene, which can be performed at lower temperatures and avoids the use of acids. Li2CO3 can be formed with > 90% yield at 750 °C by reacting α-spodumene with inexpensive additives. Following its extraction from spodumene, Li2CO3 can be isolated with high purity by washing the sample using deionized water [3]. The Li extraction process introduced above presents a low-energy and acid-free route to obtain Li2CO3 directly from spodumene, thereby fostering a more sustainable and efficient utilization of natural minerals to produce precursors that are essential for battery industry. We will also demonstrate how the in-situ formation of Li2CO3 opens new opportunities for the direct synthesis of battery materials from raw ores (α-spodumene).

References:

[1] Karrech, A., et al., A review on methods for liberating lithium from pegmatities, Minerals Engineering, 2020. 145.

[2] Yelatontsev, D. and Mukhachev A., Processing of lithium ores: Industrial technologies and case studies – A review, Hydrometallurgy, 2021. 201.

[3] Shilong, W., Nathan, S., et al., Direct lithium extraction from α-spodumene through solid-state reactions for sustainable Li2CO3 production, under review.
(Invited) A Non-Stabilized Supersaturated High-Energy-Density Storage Concept for the Redox Flow Battery and Its Demonstration in an H2-V System
Authors: Mouron Spencer T , Nguyen Trung Van
Published: December 2024

Redox flow battery (RFB)-based storage systems have the unique feature of separating power generation from energy storage, allowing individually sized systems uncoupling power from capacity. RFBs can be used for days-long energy storage, but because of the low solubility of most ions and molecules in both aqueous and non-aqueous solvents,[1,2] scaling these RFB systems for days-long applications requires significant storage tanks and floor area.

Our team has been working on a new storage method for Vanadium electrolytes that significantly increases the energy storage density while still maintaining the traditional flow battery design.[3] This method involves storing the reactants as both soluble ions and as undissolved solids, only allowing liquid-containing soluble ions to circulate through the battery. To achieve this, a solid form of Vanadium salt must be precipitated within the storage tanks, with an applied temperature swing to dissolve this solid and keep the electrolyte below saturation level for transport to the flow battery. To run this system without any form of external heating or cooling, we propose to allow saturated electrolyte to enter the flow battery during operation. This presentation will discuss the operation of a V-H2 redox flow battery system operating at 2.5 M total vanadium concentration (above the 1.8M solubility limit of VOSO4)[4] and its comparison to a more traditional sub-saturated system at 2.5M and 1.5M total vanadium ion concentrations respectively.

References

[1] V. Singh, S. Kim, J. Kang, and H. R. Byon, Nano Res.,
12, 1988-2001 (2019).

[2] K. Gong, F. Xu, J. B. Grunewald, X. Ma, Y. Zhao, S. Gu, and Y. Yan, ACS Energy Lett.,
1, 89-93 (2016).

[3] Y. Li and T. V. Nguyen, Provisional US patent application number 62/941,064 filed 2019/11/27, International Application No. PCT/US20/61455 filed 2020/11/20 (WO2021108244A1).

[4] Skyllas‐Kazacos, M.; Peng, C.; Cheng, M. Evaluation of Precipitation Inhibitors for Supersaturated Vanadyl Electrolytes for the Vanadium Redox Battery. Electrochem. Solid-State Lett. 1998, 2 (3), 121. https://doi.org/10.1149/1.1390754.

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(Invited) A Versatile Reference Electrode for Lithium Battery Use
Authors: Koch Brian , Gao Jing , Zhang Anne , Garrick Taylor R.
Published: December 2024

A thin, porous, separator-supported reference electrode disposed between an anode and cathode is proposed as a practical, implementable solution for measuring individual electrode potentials in a commercial lithium ion cell. Its precise placement at the midpoint of the cell stack and permeable layer design allow for a simple formula for the calculation anode and cathode potential, while affecting the electrochemical performance of the cell only to the extent of adding one extra separator.

In this study, we introduce a separator-supported reference electrode for both laboratory use and real-time, direct-feedback battery control systems in electric vehicles. Extraction of electrode kinetic parameters and electrode-level control of DC fast charge are shown for an NCMA/Graphite 1Ah pouch cell to demonstrate the simplicity, fidelity, and robustness of the reference electrode design.

References

1. T. R. Garrick, J. Gao, X. Yang, and B. J. Koch. J. Electrochem. Soc., 168 010530 (2021)

2. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170, 113502 (2023)

3. J. Gao, B. J. Koch, and T. R. Garrick. "Electrochemical Systems, Methods, and Devices Using Stacked Electrode Assemblies with In-Stack Sensor Arrays." U. S. Patent App. No. 17/479,558

4. H. Zhang, T. R. Garrick, and B. J. Koch. "Method and System for Charging a Battery" U. S. Patent App. No. 17/894,691

5. J. Gao, B. J. Koch, T. R. Garrick, and W. Zeng. "System and Method for In-Situ Mapping on Electrode Potential and Thermal Distribution" U. S. Patent App. No. 17/891,120

6. B. J. Koch, A. McAllister, and R. S. Conell. "Reference Electrode" U. S. Patent 10,439,256
(Invited) Two-Dimensional Covalent Organic Framework-Based Nanocomposite Membranes with Light-Enhanced Properties for Efficient Blue Energy Harvesting
Authors: Lung Chia-An , Yeh Li-Hsien
Published: December 2024

Gibbs free energy stored in the form of a salinity gradient between seawater and river water can be harvested by using an ion-selective membrane, which is the so-called blue energy harvesting. However, the development of ion-selective membranes suffers from insufficient ion selectivity, poor ion permeability, and their inherent physicochemical properties. A trade-off between ion selectivity and ion permeability of the membrane leads to the reported power density is far below the commercial benchmark (5 W/m2). Here, we report an innovative strategy to fabricate a 2D/1D lamellar nanocomposite membrane (named as T-A-P COF/ANF) for highly efficient blue energy conversion. The T-A-P/ANF consists of a mixed type of TFP -Azo-Py COF (T-A-P) with excellent light-responsive properties and the AB stacking structure to improve ion selectivity, and the aramid nanofiber (ANF) with good flexibility to maintain mechanical properties. Using a salinity gradient between seawater and river water, the T-A-P COF/ANF can generate an ultrahigh power density up to ~6.14 W/m2, surpassing the state-of-the-art nanofluidic membranes reported. Moreover, an irradiation with 365 nm ultraviolet light promotes the power output towards an unbelievable ~8.16 W/m2, which increases 32.9% compared to the pristine T-A-P/ANF membrane.

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Expanding Single-Entity Electrochemistry with Agarose Hydrogel: Enhanced Signal Stability
Authors: Na Jaedo , Kwon Seong Jung
Published: December 2024

Single-entity electrochemistry (SEE) was performed using agarose hydrogel. Typically, SEE is studied in liquid electrolytes, where challenges arise from signal variation due to nanoparticle (NP) aggregation and perturbations of background signals caused by natural convection of the liquid electrolyte. To address these issues, we conducted SEE using a solid electrolyte agarose hydrogel. First, cyclic voltammetry measurements for hydrazine oxidation were conducted to confirm differences of mass transfer characteristics between liquid electrolytes and agarose hydrogel. The experimental results confirmed that the diffusion coefficient of hydrazine in agarose hydrogel was linearly decreased with increasing agarose hydrogel concentration. Subsequently, we conducted SEE of Pt NPs for the hydrazine oxidation reaction using agarose hydrogel with various concentrations of 0.5%, 1%, and 2%. As the concentration of agarose hydrogel increased, the structure's porosity became denser, resulting in slower diffusion rates of hydrazine and NPs. These differences were analyzed by changes in the size, shape, and frequency of the signals. In agarose hydrogel, diffusion of NPs and hydrazine was slower compared to liquid electrolytes, leading to decreased signal size and frequency. However, the agarose hydrogel matrix generates more uniform signals by excluding effects from aggregated NPs and impurities. Furthermore, minimizing background current fluctuations due to natural convection increases the signal-to-noise (S/N) ratio, making signal analysis more convenient.
Room Temperature Modification of Carbon Cloth for Water Splitting
Authors: Dalla Benetta Marilia Barreto , Breslin Carmel B , Dempsey Eithne
Published: December 2024

The energy production sector has faced many challenges, especially regarding the environmental impacts caused using fossil fuels. Renewable hydrogen, generated via electrolysis of water, has emerged as a possible solution to reducing global reliance on fossil fuels as a source of energy. Many emerging catalysts are made using hydrothermal synthesis, demonstrating good water-splitting performance. However, the methods used to make such materials can be time and energy-consuming, while generating a significant quantity of chemical waste, which remain in the environment for long periods. This study focuses on the development of a new environmentally benign, solvent-free, room-temperature synthesis design taking advantage of abundant, low-cost materials.

In the first stage of this study, a room temperature deposition of Molybdate (Mo) on the surface of Nickel Foam (NF) was identified. This material resulted in a very good performance in relation to the oxygen evolution reaction (OER). However, NF is an effective catalyst for water splitting, making it challenging to discriminate the effectiveness of immobilized electrocatalysts and the formation of oxides can give false results. To address these issues, in the second phase of the work, carbon cloth (CC) was used as a substrate due to its attractive features of low cost, porosity, and lack of catalytic performance in the absence of modification.

Copper was incorporated on the CC by electrodeposition and porous copper was formed by hydrogen bubble dynamic. The Copper Foam/ Carbon cloth (CF/CC) was further modified by this novel one-pot room temperature synthetic approach. CF/CC presented a significant improvement relative to its bare form. Performance data showed good current density, impressive onset potentials, good Tafel slopes, low impedance, and good stability. Both HER and OER were tested in this study. 1–3

1 H. C. Shin and M. Liu, Chemistry of Materials, , DOI:10.1021/cm048887b.

2 M. Mottakin, V. Selvanathan, M. Ariful Islam, H. Almohamadi, N. H. Alharthi, S. Yoshimura and M. Akhtaruzzaman, Chem Asian J, , DOI:10.1002/asia.202300532.

3 P. Wang, J. An, Z. Ye, W. Cai and X. Zheng, Front Chem, , DOI:10.3389/fchem.2022.913874.

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Remediation of Aquatic Environments Contaminated with As(III) and Mn2+(aq) Using Hematite Photocatalyst
Authors: Choi Junyeong , Jung Haesung
Published: December 2024

Arsenic (As) and manganese (Mn) commonly coexist in nature and are well known to have high carcinogenic and neurotoxicity effects. Therefore, many regulatory agencies impose a maximum contamination level for As and Mn in water at 10 and 400 μg L-1, respectively. Additionally, since As and Mn often occur together, there is a need for a method that can simultaneously remove As and Mn. However, currently, As is removed using iron oxide, and Mn is removed using Mn oxide. These methods suffer from decreased removal efficiency over time and have limitations in effectively removing As(III), which is more toxic, mobile, and difficult to eliminate. Therefore, a method is needed that can effectively and simultaneously remove As(III) and Mn. In this study, we investigated the simultaneous oxidation and removal of As(III) and Mn2+(aq) using a photocatalytic reaction with hematite. The reason we used hematite is that it is one of the most abundant iron oxides in the crust and has a favorable band gap of 2.1 eV, making it suitable for photocatalytic oxidation using sunlight. We found that 0.1 g/L hematite can simultaneously and rapidly oxidize 89 μM As(III) and 44 μM Mn2+(aq) through photocatalytic process under natural sunlight. Additionally, we confirmed that a positive hole is the primary pathway for the oxidation of As(III) and Mn2+(aq). Our finding provides that As(III) and Mn2+(aq) can be effectively removed using hematite from aquatic systems contaminated with As(III) and Mn2+(aq). Moreover, our finding provides insights to understand the redox processes among As(III/V), Mn2+(aq), and hematite in natural environments.