bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanocellulose-Based Chiroptical Sensors for Detecting Circularly Polarized Light
Authors: Kang Saewon
Published: December 2024

Natural materials exhibit fascinating optical properties that manipulate light across multiple length scales through hierarchical photonic structures, forming a promising platform for advanced optical materials. However, developing photonic structures that are both environmentally sustainable and capable of maintaining superior optical and structural properties for use in electronic devices remains a significant challenge.

In this work, we present chiroptical nanocellulose papers as flexible circularly polarized light (CPL) photodetectors. Optoelectrically activated 2D semiconducting channels are seamlessly integrated onto the nanocellulose papers, enabling high polarization-sensitive photoresponsivity that detects CPL handedness, facilitated by selective light propagation with substantial asymmetry. These flexible devices also demonstrate excellent mechanical durability while retaining their structural and chiroptical properties. We will discuss polarization-dependent optoelectronic behavior in the context of CPL sensing, with applications in next-generation bio-photonic devices.
Radially Oriented Ni3(HITP)2 Microspheres: High-Performance Anodes for Li-Ion Capacitors
Authors: Yoo Jungjoon , Kang Sanghui , Kim Bumjin , Baek JeongHun , Lee Chan-Woo
Published: December 2024

Creating high-energy, high-power-density energy storage devices poses a significant challenge. Despite their potential as electrode materials for such devices, metal–organic frameworks (MOFs) face issues like poor electrical conductivity and weak ligand–metal coordination. In this study, we employ a highly conductive MOF called Ni3(HITP)2, consisting of radially oriented microspheres, as the anode for Li-ion capacitors (LICs). Our experiments show that the half-cell exhibits a notable reversible capacity of 834 mAh g−1 at 50 mA g−1 with minimal capacity degradation. This performance can be attributed to the involvement of carbon and nitrogen functional groups from the ligand and Ni2+ ions in the redox reactions during charge/discharge cycles. Particularly, density functional theory calculations reveal that the outer rings of Ni3(HITP)2, in addition to the inner ones, contribute significantly to the high Li+ storage capacity. When integrated into an LIC setup with a Ni3(HITP)2 anode and a commercial activated-carbon cathode, the system achieves a high specific energy of 120.7 Wh kg−1 at 89.2 W kg−1, nearly doubling the performance of graphite-based LICs. Moreover, it maintains a specific energy of 25.8 Wh kg−1 even under high specific power (7.16 kW kg−1) across the voltage range of 1–4.4 V, while exhibiting excellent cycling stability (76% capacity retention over 10000 cycles). These findings suggest that radially oriented Ni3(HITP)2 microspheres hold promise for enhancing the performance of energy storage devices, particularly as anodes.

Acknowledgement: This research was supported by the National Research Council of Science & Technology(NST) grant by the Korea government (MSIT) (No. CAP22072-000).
Cathode Reaction Analysis of Lithium-Oxygen Battery Based on Operando XRD Measurements
Authors: Maeda Kazuno , Aoki Makoto , Dilixiati Dilinigeer , Kondo Toshihiro
Published: December 2024

Introduction

The lithium-air battery (LAB), which has ten times the energy density of conventional lithium-ion batteries (LIB), is one of the promising candidates for the next-generation storage batteries, and there are great expectations for its development [1]. However, the reaction mechanism of the cathode reaction is still unclear, and the type of Li2O2 that is the product of the cathode in discharging is still unknown. The main reason for this is considered to be that it was difficult to directly observe the compounds generated at the cathode during LAB operation. By improving the laboratory XRD and the observation cell, we succeeded in operando XRD measurements of the cathode reaction in the LAB. In addition, under general conditions, the cathode product was Li1.5O2 with some Li missing from the crystal lattice of Li2O2 [2]. Here, we describe the details and discuss the reaction mechanism.

Experimental

An electrochemical cell covered with a Kapton® dome was constructed to allow constant oxygen flow to the cathode side of the LAB, and was attached to the diffractomator of a Rigaku Ultima IV XRD measurement system. A Cu Ka was used as the incident x-ray, a high-speed one-dimensional detector was used as the detector, a Ketjen black free-standing film was used as the cathode material, and tetraglyme solution with 0.5 M LiTFSI + 0.5 M LiNO3 + 0.2 M LiBr was used as the electrolyte solution. The LAB was discharged and charged at a constant current density of 0.4 mA/cm2 for 10 hours (4.0 mAh/cm2) each, and the XRD profile was recorded every 20 minutes. Each XRD profile was subjected to Rietveld analysis using Rigaku’s SmartLab Studio II software to determine the cathode product and its crystal structure.

Results and discussion

In the XRD profile measured during discharging, a lot of peaks due to the cell parts were observed. But, several peaks due to the cathode product were also observed. As a result of detailed Rietveld analysis of these peaks, the cathode product at the discharging capacity of 4.0 mAh/cm2 was not Li2O2 but Li1.5O2. Instead of the normal LiO2 with a rectangular crystal structure, LiO2 with a hexagonal crystal structure, which is the same as that of Li2O2, was observed immediately after the discharge. As the discharge progressed, Li was added to it, and the lattice constant gradually extended in the c-axis direction, forming Li1.5O2 at a discharge of 4.0 mAh/cm2. In the presentation, the charging process and the charge-discharge cycle characteristics would also be discussed.

References

[1] W. J. Kwak, et al., Chem. Rev.
120, 6626 (2020).

[2] M. Aoki and T. Kondo, et al., J. Phys. Chem. C
127, 15051 (2023).
High-Performance Solid-State Li Metal Batteries Based on a Solid Polymer Electrolyte
Authors: Wang Peng , Bucur Claudiu , Andrei Petru
Published: December 2024

Over the past decades, lithium-ion batteries (LIBs) have garnered considerable attention, emerging as the foremost commercial battery technology. Widely employed in portable electronics, electric vehicles, and energy storage stations, LIBs face challenges including safety concerns and low energy densities, prompting extensive research into next-generation battery technologies. Solid-state batteries are recognized as one of the most promising alternatives to conventional LIBs. Polymer-based solid-state electrolytes have garnered extensive attention for their softness and flexibility, offering relief from interface issues between electrodes and separators in contrast to inorganic solid electrolytes. Nonetheless, their drawbacks, including limited Li+ conductivity or narrow electrochemical windows (< 4 V), constrain their potential applications.

This presentation introduces a novel solid-state electrolyte (SSE) derived from a new polymer developed by Piersica Inc. (www.piersica.com), tailored for use in all-solid-state lithium metal batteries. The SSE exhibits remarkable conductivity (0.2 mS/cm) at room temperature and exceptional oxidized stability (approximately 4.9 V). When integrated into a solid cathode and lithium metal anode configuration, without the addition of any liquid electrolyte, the resulting solid-state pouch cell (~40 mAh) demonstrates over 90% of theoretical capacity, superior rate performance, and long-term stability (85% retention after 200 cycles) at room temperature. The polymer from Piersica Inc. holds considerable promise for advancing the development and performance of solid-state batteries.
Nitrogen-Doped Mesoporous Carbons Fabricated from Self-Assembled Block Copolymers for Electrochemical Production of H2O2
Authors: Kong Youngwon , Miyamori Yuta , Hatakeyama-Sato Kan , Hayakawa Teruaki , Nabae Yuta
Published: December 2024

Nitrogen-doped mesoporous carbons are attracting significant attention as next-generation electrocatalytic materials due to their high specific surface area, high electrical conductivity, and exceptional chemical stability. Especially, due to the facilitated mass transport of products, high selectivity for the two-electron oxygen reduction reaction is expected, making it applicable to the synthesis of hydrogen peroxide (H2O2).¹ In this study, we focused on the soft template method by utilizing the self-assembly of a block copolymer (BCP) through microphase separation.² In our laboratory, we have been working on the synthesis of poly(4-vinylpyridine)-b-poly(2,2,2-trifluoroethyl methacrylate) (P4VP-b-PTFEMA). The significant repulsive interaction between these two components allows extensive control of the domain size. Furthermore, poly(4-vinylpyridine) serves as both the nitrogen and carbon sources and is selectively crosslinked by resol, thus enabling a high carbonization yield to be obtained. We employed this BCP as a soft template and introduce resol as a cross-linker for fabricating nitrogen-doped mesoporous carbons. Here, we investigated in detail the effects of the composition of the block copolymer and the amount of the crosslinker on the morphology and nitrogen content of the mesoporous carbon.

P4VP-b-PTFEMA was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. A mixture of P4VP-b-PTFEMA and resol was dissolved in DMF at 5 wt%, and the solution was evaporated and dried under vacuum at 100 °C for 24 hours to prepare a composite film. Subsequently, the film was heated to 900 °C to fabricate nitrogen-doped mesoporous carbons.

Small-angle X-ray scattering (SAXS) analysis of the composite film revealed various microphase-separated structures depending on the BCP-to-resol ratio (Fig. 1 (a)). Furthermore, nitrogen-doped mesoporous carbons with pore diameters ranging from 6.2 nm to 24 nm were fabricated using various molecular weights of PTFEMA (Fig. 1 (b)). Additionally, in our presentation, we will discuss how the pore size affects the selectivity of the two-electron reaction and the catalytic efficiency in the oxygen reduction reaction.

[Reference]

(1) Park et al., ACS Catal. 2014, 4, 3749.

(2) Liu et al., Polym. Chem.
2014, 5, 6452.

[Acknowledgement]

This study was financially supported by JSPS-KAKENHI(21K04828).

Figure 1
Impedance Analysis on Ant-Nest Corrosion of Copper- Effect of Phosphorus Content in Copper on Corrosion Morphology-
Authors: Kashiwa Takumi , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki , Ito Shinichi , Hosogi Tetsuro
Published: December 2024

In recent years, leakage of refrigerant due to ant-nest corrosion has become a problem in copper piping used in heat exchangers of air-conditioning equipment.1) In our laboratory, we have succeeded in electrochemically reproducing ant-nest corrosion by galvanostatic polarization of phosphorus-deoxidized copper immersed in 600 ppm, formic acid solution of pH 5.5 at a current density of 0.3 mA/cm2..2) The pits of ants-nest corrosion have a fractal structure with a repetitive branching shape. Our laboratory reported that the number of branching in ant-nest corrosion can be determined by using a transmission line model (TLM) with blanched structure equivalent circuit from impedance spectra.3) Furthermore, the oxidation phosphorus dissolved from copper causes a decrease in pH at the bottom of the small pore, and the pH decrease accelerates the branching. In this experiment, galvanostatic polarization was applied to copper tubes with different phosphorus contents as working electrodes to reproduce ant-nest corrosion. Furthermore, the number of branching of ant-nest corrosion was determined by impedance analysis using TLM. Based on these results, the effect of phosphorus content on corrosion morphology was discussed.

Experimental conditions:

The electrolyte solution was a 600 ppm formic acid solution of pH 5.5. Copper tubes with various phosphorus contents (0.003, 0.004, 0.007, 0.015, 0.31 wt%) were used as working electrodes. The outside of the copper tube was used as the working electrode (test surface), and the rest of the test surface was covered with insulating tape to define the electrode area (electrode area: 7.85 cm2). In addition, the bottom hole of the copper tube was covered with a rubber stopper to prevent the solution from entering to inside of the copper tube. The test surface was polished with abrasive papers No. 800, 1200, and 2000, polished with diamond pastes of 6, 3, and 1 μm particles diameters, and then cleaned with methanol. Constant current polarization was performed for 72 h at a current density of 0.3 mA/cm2 using a platinum wire as a counter electrode, a saturated KCl silver/silver chloride electrode (SSE) as a reference electrode.

References

1) S. Ito, T. Hosogi, M. Watanabe, H. Tsueoka, M. Itagaki, Zairyo-to-Kankyo，67, 37-40 (2018).

2) M. Itagaki, A. Makita, H. Watanabe, I. Shitanda, T. Hosogi, S. Ito, Electrochim. Acta 479, 143873 (2024).

3) M. Itagaki, Y. Hatada, I. Shitanda, K. Watanabe, Electrochim. Acta 55, 6255–6262 (2010).
Thermodynamic Analysis of Asteroid Mining Systems: Insights from Optical Mining Bag Materials
Authors: Sare Hadarou , Dong Dongmei
Published: December 2024

This study investigates the thermodynamic behaviors of materials within an optical mining system aimed at extracting water from asteroids. The spacecraft utilizes solar reflectors to concentrate sunlight onto the captured asteroid, initiating the extraction process. The focus lies on analyzing the thermodynamic properties of the asteroid mining bag, constructed with layers of Nomex (outer layer), Kevlar (supporting layer), and a PANI thin film (inner layer). Through a MATLAB Simulink model, a 10-day mining simulation is conducted, revealing the system's capability to extract water at a rate of 77 g/s. Key parameters such as temperature, pressure, heat flow rate, and gas flow rate are measured within the mining bag. Additionally, the study accounts for thermal insulation effects on the asteroid bag and heat losses to the surrounding environment. The thermodynamic equations governing heat transfer, mass conservation, and energy within the asteroid bag are analyzed, providing insights into the efficiency and effectiveness of the mining process. This research contributes to understanding the thermodynamic principles underlying asteroid mining operations and guides future developments in this field.
Preparation of Ordered Nanohole Arrays by Anodization of Textured Metal Substrates
Authors: Umeki Kota , Yanagishita Takashi
Published: December 2024

The anodization of metals can form nanohole array structures composed of various metal oxides. The resulting anodic oxide film is expected to be used in various applications, such as catalysts, electrodes, and sensors, because of the material's properties and unique geometric structure. When applying nanohole arrays obtained by anodization of metal substrates to various functional devices, it is important to control geometrical structures such as pore size and pore depth, which affect device performance. We previously reported that forming a pattern of depressions on substrate surfaces prior to anodization allows the formation of ordered nanohole arrays by subsequent anodization [1–3]. In previous studies, the depression pattern was formed by dry etching with a mask, which made it impossible to increase the area of the pattern. In this study, we investigated the formation of depression patterns using a template process and the control of the starting point of pore generation by anodic oxidation to form large-area ordered nanohole arrays. Herein, we present the results of our study using Sn as the model material.

Anodized porous alumina, which can self-assemble large-area ordered structures, was used as a template to form ordered depression patterns on the Sn substrates. An ordered anodic porous alumina membrane, used as a template, was obtained by selectively dissolving the Al substrate from the anodized sample. The Sn thin film was formed on the back side of the obtained template by thermal evaporation and electrodeposition, and the alumina membrane was peeled off to obtain a Sn thin film with an ordered depression pattern on the surface. The resulting Sn thin film was anodized to generate holes from each depression, resulting in an ordered nanohole array.

SEM observations confirmed that the ordered pattern on the anodic porous alumina backside was successfully transferred to the Sn surface by this process. Anodization of the obtained Sn thin films induced pore generation from each depression, resulting in ordered nanohole arrays. This process is expected to produce large-area ordered nanohole arrays because the anodic porous alumina used as a template can be fabricated in large areas. The Sn oxide nanohole arrays obtained by this method are expected to have various applications.

References

[1] T. Yanagishita T. Masuda, T. Kondo, and H. Masuda, Electrochem. Commun., 123, 106916 (2021).

[2] T. Yanagishita, T. Masuda, and H. Masuda, RSC Adv., 12, 6848 (2022).

[3] T. Yanagishita, Y. Osada, T. Masuda, and H. Masuda, J. Electrochem. Soc., 169, 063502 (2022).
Reaction of Calcium Titanate with Al Metal in Molten CaCl2
Authors: Kaneda Hisayoshi , Takenaka Toshihide
Published: December 2024

A new innovative production process of Ti production replacing the Kroll process is desired. The authors have been researching the production of Al-Ti alloy by Al reduction of TiO2 in molten CaCl2. It was shown in our previous study that Ti was reduced by the reaction of Al metal and CaTiO3 in molten CaCl2 at 1500°C, and that excess CaO addition was effective. However, the Ti content in the obtained Al-Ti alloy was still very small. In this study, the effect of Al-Ti alloy formation in molten CaCl2 containing Ca4Ti3O10 was investigated, and the appropriate condition for Al-Ti alloy formation was studied.

Calcium titanate: Ca4Ti3O10 was prepared by sintering a molded mixture of CaO and TiO2, and a small Al lump was used as reductant. The influence de-greasing of the Al lump by NaOH solution as pretreat was examined in this study. Molten CaCl2 containing Ca4Ti3O10 with the Al lump was kept for 1~1.5 hour at 1400°C~1450°C, and cooled down. The Al lump after the experiment was rinsed with pure water, and analyzed by XRD and SEM-EDX.

Figure 1 shows the dependence of Ti content in the Al lump on the immersion time. A small amount of Ti was detected in Al lump, and the Ti content varied with the immersion time. In the case that the Al lump without the pretreatment was used, the Ti content slightly increased with the immersion time, but the content was only 0.32 at% for 1.5 hour immersion at 1400°C. It was shown in our previous study that the Ti content was 0.06 at% in molten CaCl2 with CaTiO3, and that the content became 0.62 at% in the bath containing CaTiO3 with extra CaO where the molar ratio of CaO to TiO2 was 4:3. The result in this study is consistent with our previous study, which implies that the type of titanate ion in the bath strongly affects its chemical reduction by Al. The pretreatment of the Al lump strongly affected the Ti content; in the case that the Al lump with the pretreatment was used, the Ti content remarkably increased with the immersion time, and the content became 6.74 at% for 1.5 hour immersion. Since the Ti content did not reach a plateau even after 1.5 hour, a higher Ti content is expected by longer immersion. The Ti contents at 1400°C and 1450°C were almost the same, so the temperature dependence of this reaction seems not significant. Since the reaction seemed not to reach the equilibrium and the Ti content in Al was still insufficient, a further investigation should be necessary for the development of effective Ti production by this method. The researches on the influence of the titanate concentration and on the interface control other than de-greasing can lead more effective reaction.

Figure 1
Electrochemical and Spectroscopic Analyses for Extracted Rh(III) Complex in Phosphonium-Based Ionic Liquids
Authors: Tokumitsu Shun , Matsumiya Masahiko , Sasaki Yuji
Published: December 2024

In this study, the phosphonium-based ionic liquids (IL) have been investigated for the extraction of Rh(III). The ion-pair extraction of Rh(III) was confirmed by slope analysis with the concentration dependence of the phosphonium cation. On the other hand, the IL-Rh(III) complex was identified by means of UV-Vis-NIR and Raman spectroscopic analyses. According to the spectroscopic analysis, the extracted IL-Rh(III) complex found to be present in IL medium and the [NTf2]- anion is not coordinated at the first coordination sphere. In addition, the electrochemical analysis revealed that the extracted Rh(III) can be reduced to Rh(0) by a single step. The diffusion coefficient of the extracted Rh(III) was also evaluated from the semi-differential analysis. Furthermore, the electrodeposits can be recovered from continuous solvent extraction and electrodeposition process. Consequently, SEM/EDX, XPS and XRD identified the electrodeposits as predominantly Rh metal.
A Novel Process to Achieve Enhanced Mechanical and Electrical Properties of (Mn,Co)3O4-Based Electrical Contact Layer for Solid Oxide Cells
Authors: Adjah-Tetteh Christabel , Wang Yudong , He Zizhou , Xu Nengneng , Zhou Xiao-Dong
Published: December 2024

To reduce ohmic losses and increase power output in an SOFC stack, electrical contact materials have been employed between the interconnect and oxide cathode. One of the possible candidate materials for the electrical contact layer is (Mn, Co)3O4, which is also used as the interconnect coating in an SOFC stack, due largely to its coefficient of thermal expansion that matches with the interconnect and cathode [1, 2]. The (Mn, Co)3O4 is electrically conducting, yet its conductivity remains several orders of magnitude lower than certain perovskite counterparts, such as (La, Sr)CoO3. In addition, (Mn, Co)3O4 often requires high sintering temperature (≥ 1000°C) when the oxide powders are used as starting materials [1, 3]. There is a need to develop novel processes to reduce the sintering temperature of (Mn, Co)3O4 to about 850°C, at which the sealing glass is sintered. In this work, we employ a new approach to fabricate (Mn, Co)3O4 spinels as the electrical contact materials. This innovation significantly enhanced the conductance of the contact layer and its bonding strength. The bonding strength with interconnect is evaluated by evaluating the maximum shear stress when the spinel layer is sandwiched by two 430 stainless steel coupons. Electrical resistance is measured for the contact layer with different Mn-Co ratios.

References

[1] J. H. Zhu and H. Ghezel-Ayagh, "Cathode-side electrical contact and contact materials for solid oxide fuel cell stacking: A review," International Journal of Hydrogen Energy, vol. 42, no. 38, pp. 24278-24300, 2017.

[2] Z. Yang, G. Xia, and J. W. Stevenson, "Mn1. 5Co1. 5 O 4 spinel protection layers on ferritic stainless steels for SOFC interconnect applications," Electrochemical and Solid-State Letters, vol. 8, no. 3, p. A168, 2005.

[3] A. Petric and H. Ling, "Electrical conductivity and thermal expansion of spinels at elevated temperatures," Journal of the American Ceramic Society, vol. 90, no. 5, pp. 1515-1520, 2007.
Activity and Stability of Ruir Binary Oxides with Different Ir/Ru Ratios for Oxygen Evolution Reaction in Acidic Environmental
Authors: Banno Akichika , Negishi Mayu , Maruyama Takahiro , Saida Takahiro
Published: December 2024

Proton exchange membrane water electrolysis (PEMWE) is one answer for the mass production of hydrogen. However, PEMWE requires relatively high electric power because the oxygen evolution reaction (OER) at the anode has a high overpotential. In addition, IrO2, used as the general anode catalyst of PEMWE, is very expensive. Although it is known that RuO2 shows higher OER activity and lower cost than that of IrO2, the stability of RuO2 is quite low. Naturally, it is desirable to improve the OER activity in IrO2 or to enhance the stability of RuO2.

Wu et al. reported that the RuIr nano coral with 6% Ir content showed high OER activity and stability [1]. In contrast, the majority of previous reports employed around 50% Ir contents, and the variation range of Ir contents in RuIr catalyst was large, such as 25%, 50%, and 75% of Ir. Therefore, it is difficult to judge the effect of a tiny amount of Ir content on OER activity and stability at this time. The OER activity and stability of RuIr nano coral may originate from the nano coral shape rather than Ir content.

This study focused on the Ir/Ru ratio in RuIr binary oxide to investigate the effects of a tiny quantity of Ir atoms in RuO2 on OER activity and stability. The catalyst shape limited the nanoparticle and excluded the effect from the shape.

The different compositions of RuIr binary oxides were synthesized by the Adams method. The Ir ratio was controlled at about 1%, 2%, 5%, 10%, and 50%, respectively. The atomic composition of synthesized samples was estimated using XRF analysis. The electrochemical measurement was conducted by a three-electrode cell composed of a working electrode, a Pt wire counter electrode, an Ag/AgCl reference electrode, and 0.5 M H2SO4 (room temp.). In addition, a working electrode was rotating at 4,000 rpm during the electrochemical measurements. In this study, the potential was converted to vs. RHE from vs. Ag/AgCl.

All synthesized catalysts had a rutile-type crystal structure. With the increase in Ir contents, the crystallite size increased from ~1 nm to 3.6 nm. The Ir rates relative to total metal atoms in the synthesized samples were 1.3%, 1.8%, 4.5%, 13.5%, and 46.8%. OER activity at the initial state was improved in comparison with RuO2 when the Ir ratio was 5%. On the other hand, stability at 1.7 V was decreased in samples with a low Ir ratio. In the case of stability, a relatively high Ir ratio sample would be favored.

The results of this study could indicate that initial OER activity is dependent on the Ir ratio of RuIr binary oxide, and stability may be affected by the catalyst shape.

[1] Dongshuang Wu et al, nature comunication (2021) 1-9.
Electrochemical Pump for Hydrogen Separation and Purification from Exhausted Gas Mixture
Authors: Jung Hyemin , Choi Jung Min , Choi Insoo
Published: December 2024

The hydrogen economy is a vital strategy for mitigating climate change and energy security through the establishment of an environmentally sustainable energy framework. To use hydrogen as a stable fuel, high purity is essential. Hydrogen separation technology can be classified into two types: Pressure Swing Adsorption (PSA) and Electrochemical Hydrogen Pump (ECHP). PSA operates by adjusting the pressure to release the adsorbed gas. It has disadvantages such as complexity, large footprint and high energy consumption. The electrochemical hydrogen pump is a technology that can overcome these disadvantages. Electrochemical hydrogen pump consists of electrode, gas diffusion layer, catalyst, and proton exchange membrane. Among these components, the catalyst is a direct factor affecting the performance and durability. Pt, mainly used as a catalyst, is known to have excellent performance in the HOR and HER. However, it suffers from CO2 poisoning, which causes performance degradation. As the requirement of hydrogen separation in gas mixture has increased, the need for a catalyst that can maintain performance under exhausted gas mixture. This study manufactures Iridium-based catalyst electrodes with strong resistance to CO2 poisoning. We deposit an Iridium oxide layer onto Carbon paper using an electrochemical deposition method, enabling the formation of thin and uniform catalyst layers by adjusting the voltage and time. Through a thermal reduction process, we form a metallic Iridium layer on the surface. The application of electrode with thin and uniform Ir/IrOx catalyst layer to lab-scale ECHP is expected to improve long-term performance.
The Influence of Fluoroalkyl Group in Alcohol on the Interaction between Alcohols and Fluoride Ion
Authors: Yoneda Nozomi , Tada Kohei , Matsumoto Kazuhiko
Published: December 2024

Fluoride ion combined with large cations shows high basicity and reactivity. Taming F− with a hydrogen bonding donor such as an alcohol can moderate its basicity, sometimes enabling its effective use in chemical and electrochemical reactions.[1][2] Alkali metal fluoride−alcohol systems are interesting candidates because of its high solubility of F−, basicity, and chemical and electrochemical stability, and simple preparation. This study focuses on CsF−IP (2-propanol) and CsF−HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) systems. Electrochemical behavior of HFIP-based electrolytes was investigated recently owing to its high oxidative stability.[3][4]

In this study, the structural and physical properties of the CsF−HFIP and CsF−IP systems were comparatively discussed. The interaction energy calculations revealed that the interaction between HFIP and F− is stronger than that between IP and F−, which involves the conformational change of HFIP. The peak shift in IR and 1H NMR spectra and the decrease in activity coefficient of alcohols upon the addition of CsF also identified the strong OH∙∙∙F− interaction in the CsF−HFIP system. All these observations suggested that introduction of fluoroalkyl group to an alcohol strengthens the interaction between the OH and F−, which facilitates the dissociation of the cation and anion and enhances the ionic conductivity as also indicated by the diffusion coefficient measurements. On the other hand, IP can also dissolve CsF to a high concentration but the cation and anion highly associate in the solution without giving a sufficient number of conductive species compared to CsF−HFIP system.

References:

[1] J. W. Lee, M. T. Oliveira, H. B. Jang, S. Lee, D. Y. Chi, D. W. Kim, C. E. Song., Chem. Soc. Rev.
45, 4638-4650 (2016).

[2] K. M. Engle,V. Gouverneur., Chem Sci , 6, 5293-5302 (2015).

[3] R. Francke, D. Cericola, R. Kötz, D. Weingarth, S. R. Waldvogel, Electrochim. Acta, 62, 372-380 (2012).

[4] N. Shida, H. Takenaka, A. Gotou, T. Isogai, A. Yamauchi, Y. Kishikawa, Y. Nagata, I. Tomita, T. Fuchigami, S. Inagi, J. Org. Chem., 86, 16128-16133 (2021).
Advancements in Paper-Based Electrochemical Sensors for Cancer Biomarker Detection
Authors: Begay Makeiyla , Wilson Katelyn , Platero Justin , Platero Joshua , Plummer Dallen , Billey Wayant , Soundappan Thiagarajan
Published: December 2024

Cancer is currently the third leading cause of death among the people of the Navajo Nation and is the most common cause of death worldwide. American Indians are often diagnosed when cancer has reached the advanced stages compared to other communities. Major contributors for the cancer inside the Navajo Nation is the exposure to uranium, other heavy metals, and radon gas. In the Navajo Nation, uranium mining boomed from 1944 to 1986; decades later, uranium tailings and toxic waste from the milling process have caused an increased rate of cancer in the Navajo Nation.

Further cancer detection and monitoring remain critical challenges in healthcare. This research explores the fabrication of paper-based electrochemical sensors modified with nanoparticles and antigens at the Nanoelectrochemical Analysis and Energy Storage Laboratory (NEST LAB) at Navajo Technical University (NTU) for the sensitive and selective detection of cancer biomarkers.

These electrochemical sensors harness the unique qualities of paper, such as low cost and ease of fabrication, combined with the specific binding capabilities of nanoparticles and antigens. Modifying paper electrode surfaces enhances sensitivity and selectivity, making these sensors a cost-effective and portable option for early cancer detection. In contrast to traditional methods like imaging and biopsies, electrochemical sensors are low-cost, offer minimally invasive screening, high sensitivity, and affordability, making them valuable tools in the early diagnosis and management of cancer. These sensors' accessibility and potential to detect cancer at its earliest stages can significantly improve patient outcomes, particularly in resource-limited areas such as Native American reservations.

Keywords: Cancer biomarkers, paper-based electrochemical sensors, nanoparticle modification, antigen modification, early detection, point-of-care diagnostics, cost-effective healthcare.
Rational Design of Pyrene and Thienyltriazine-Based Conjugated Microporous Polymers for High-Performance Energy Storage and Visible-Light Photocatalytic Hydrogen Evolution from Water
Authors: Sharma Santosh , Sharma Santosh U. , Kuo Shiao Wei , Elsayed Mohamed Hammad , Mekhemer Islam M.A. , Meng Tso Shiuan , Chou Ho-Hsiu
Published: December 2024

Conjugated microporous polymers (CMPs) have found extensive applications in various fields, such as optoelectronics, CO2 capture, and catalysis. However, their potential in electrochemical supercapacitors as energy storage and H2 production systems remains relatively unexplored. This limited exploration can be attributed to certain challenges, including issues related to structural and electrochemical stability, as well as the relatively modest specific capacitance. Additionally, many of the CMPs discovered thus far have exhibited lower energy densities, further contributing to this underexplored aspect of their utility. In this study, we prepared two different CMPs [TPET-TTh and PyT-TTh CMPs] containing thienyltriazine units (TTh) for the redox mechanism and constructed electrodes for supercapacitor applications. The synthesized TPET-TTh and PyT-TTh CMPs displayed exceptionally high specific surface areas of 545 and 528 m² g⁻¹, respectively. Furthermore, their pore sizes were very similar, centered at approximately 0.39 and 0.36 nm, respectively. To evaluate their electrochemical properties, the TTh-CMPs were examined using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). The resulting CV curves exhibited rectangular shapes, indicative of the characteristic behavior of electric double-layer capacitors, across a range of potential and scan rates. These TPET-TTh and PyT-TTh CMPs delivered nominal specific capacitances of 74 and 76 F g−1 at 0.5 A g−1, respectively. In addition, they exhibited outstanding capacity retentions of 95.2 and 97.30 % even after 2000 cycles [analyzed at 10 A g−1]. The TTh-CMPs also exhibited excellent light-capture capabilities. The PyT-TTh CMP has faster charge separation and lower charge recombination rates than TPET-TTh CMP. This results in a higher hydrogen evolution rate from the water decomposition reaction. The H2 production rate of PyT-TTh CMP could be as high as 18,533 μmol g−1 h−1, which is approximately 4-fold that of TPET-TTh CMP. This study offers a strategy for the design of TTh-containing CMPs that exhibit exceptional energy storage application and photocatalytic efficiency for H2 evolution.

Figure 1
(Invited) Photocatalytic Water Splitting to Form Green Hydrogen
Authors: Kudo Akihiko
Published: December 2024

Photocatalytic water splitting is a promising reaction to solve resources, energy, and environment issues, and achievement of carbon neutrality, because it produces green hydrogen. This reaction is regarded as artificial photosynthesis because light energy is converted to storable chemical energy. There are several systems for green hydrogen production; a PV cell + electrolyzer system, a photoelectrochemical cell, and a photocatalyst system. Among them, the powder-based photocatalyst system is expected to be a low-cost technology. In the present paper, various metal oxide and sulfide powdered photocatalysts for water splitting are introduced and discussed.

Rh0.5Cr1.5O3/AgTaO3 (BG 3.4 eV) of a valence-band-controlled metal oxide photocatalyst gave 40% of a quite high apparent quantum yield at 340 nm as a single particulate photocatalyst [1]. However, a solar to hydrogen conversion efficiency was 0.13% because this photocatalyst with a wide band gap responds to only UV light. It is a challenging topic to develop photocatalysts responding to light with long wavelength. Rh and Sb-codoped SrTiO3 photocatalyst loaded with IrO2 cocatalyst was active for water splitting into H2 and O2 under visible light and simulated sunlight irradiations as a single particle type photocatalyst [2]. This photocatalyst responds to 520 nm of visible light. Moreover, we have recently developed Ir-doped SrTiO3 that showed the activity for water splitting responding up to 600 nm of visible light.

There are Z-scheme photocatalyst systems for water splitting under visible light irradiation. SrTiO3:Rh and several metal sulfides of a H2-evolving photocatalyst and BiVO4 of an O2-evolving photocatalyst constructed various type of Z-schematic photocatalyst systems with Fe3+/Fe2+, [Co(bpy)3]3+/2+, [Co(phen)3]3+/2+, and a conductive reduced graphene oxide (RGO) as an electron mediator and even without an electron mediator [3]. Various types of Z-scheme systems for water splitting under visible light irradiation were also successfully developed by employing Rh- and Ir-doped metal oxide powdered materials with relatively narrow energy gaps (EG) to utilize wide range of visible light [4].

References

[1] K. Watanabe, A. Iwase, A. Kudo, Chem. Sci.,
2020
,11, 2330.

[2] R. Asai, H. Nemoto, Q. Jia, K. Saito, A. Iwase, A. Kudo, Chem. Commun. Chem.,
2014
, 50, 2543.

[3] T. Kato, Y. Hakari, S. Ikeda, Q. Jia, A. Iwase, A. Kudo, J. Phys. Chem. Lett.,
2015
, 6, 1042.

[4] A. Kudo, S. Yoshino, T. Tsuchiya, Y. Udagawa, Y. Takahashi, M. Yamaguchi, I. Ogasawara, H. Matsumoto, A. Iwase, Faraday Discussions, 2019, 215, 345.
(Invited) The Impact of "Fujishima-Honda Effect" in the Early Stage of Photoelectrochemical Research
Authors: Uosaki Kohei
Published: December 2024

Studies on semiconductor electrochemistry have been actively carried out since the 1950's mainly from fundamental points of view. Many reviews and books were published by the early 1970s (1-7). The paper by Fujishima and Honda on "Electrochemical Photolysis of Water at a Semiconductor Electrode" was published in Nature in 1972 (8) and it became very important as the 1st oil crisis took place in 1973 as this paper suggested that solar energy may be directly converted to chemical energy, hydrogen, by using semiconductor/aqueous electrolyte solution/metal cells.

In this talk, I will describe the impact of the "Fujishima and Honda Effect" in the early days of photoelectrochemical research.

References

Green, in Modem Aspects of Electrochemistry, No. 2. Ed. by J. O'M. Bockris, Butterworths, London, 343-407 (1959).

F. Dewald. in Semiconductors. ACS Monograph, No. 140, Ed. by N. B. Hannay, Reinhold, New York, 727-752 (1959).

Gerischer.in Adv. Electrochem. Electrochem. Eng., Vol. 1, Ed. by P. Delahay, lnterscience, New York, 139-232 (1961).

P. Holmes. Ed., The Electrochemistry of Semiconductors, Academic. London, 1962.

V. Myamlin and Yu.V. Pleskov, Electrochemistry of Semiconductors. Plenum, New York. 1967.

Gerischer, in Physical Chemistry: An Advanced Treatise, Vol. IXA. Ed. by H. Eyring. Academic. New York. 1970, Chap. 5.

R. Morrison, Prog. Surf. Sci., 1(1971) 105.

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

PV 77-3, "Semiconductor Liquid-Junction Solar Cells", by A. Heller.

PV 82-3, "Photoelectrochemistry: Fundamental Processes and Measurement Ed. by W. L. Wallace, A. J. Nojik, and S. K. Deb.

PV 88-14, "Photoelectrochemistry and Electrosynthesis on Semiconducting Materials", by D.S. Ginley, A. Nojik, N. Armstrong, K. Honda, A. Fujishima, T. Sakata, and T. Kawai.
(Invited) Investigation of Borophene-like 2D Materials for Electronic Devices and Electrocatalysis
Authors: Kambe Tetsuya , Sallier de la Tour Nicole , Masaoka Shigeyuki
Published: December 2024

Graphene has been the focus of countless research efforts across multiple fields. Nowadays, various 2D materials, including metal complex nanosheets, have been reported. In our previous work, we investigated the bottom-up synthesis of metal complex nanosheets (1) and atomicity-controlled clusters.(2) In this study, we achieved a single-layer material like graphene by using boron elements.(3) The prepared atomic boron nanosheet also demonstrated a liquid crystalline nature.(4) The properties are attractive for the application of electronic devices and the support of catalysts.

The atomically flat boron network skeleton was synthesized through a simple solution-based method from KBH4. X-ray diffraction analysis, electron microscopy, IR spectroscopy, and atomic force microscopy revealed the 2D structure, wherein layers of boron atoms with oxygen atoms to form a hexagonal 2D network were sandwiched between layers of potassium cations. The characteristic conducting properties of stacked borophene sheets were also revealed through temperature dependence experiments. Additionally, the liquid crystalline feature was achieved through chemical modification. The obtained liquid crystal exhibited high thermal stability and was applied to a switching device driven by electronic stimuli. In this presentation, we also show the details of a composite with a pentanuclear iron complex (5) with high activity for electrocatalytic water oxidation.

[References] (1) T. Kambe, et al.
J. Am. Chem. Soc.
2013, 135, 2462; J. Am. Chem. Soc.
2014, 136, 14357. (2) T. Kambe, et al. Nat. Commun.
2017, 8, 2046. (3) T. Kambe, et al.
J. Am. Chem. Soc.
2019, 141, 12984; Dalton Trans., 2023, 52, 15297. (4) T. Kambe, et al.
Nat. Commun.
2022, 13, 1037. (5) S. Masaoka, et al.
Nature
2016, 530, 465.
Synthesis of Halide-Substituted Bismuth Compounds for Extreme Ultraviolet Photoresist
Authors: Kim Youngkwon
Published: December 2024

As semiconductor devices become increasingly miniaturized, there is a growing need for photoresist materials capable of forming ultra-fine patterns with high etching resistance and low exposure requirements. This study introduces a series of bismuth compounds designed for extreme ultraviolet (EUV) lithography. By using simple synthetic routes involving triphenylbismuth and carboxylic acid derivatives, we successfully developed four distinct compounds with varying halide substitutions, demonstrating significant potential in high-resolution pattern formation. We synthesized four bismuth compounds using phenyl and acetate ligands, with the key difference being the halide groups attached to the acetate termini. These compounds are: triphenylbismuth diacetate (TPBA), triphenylbismuth bis(fluoroacetate) (TPBF), triphenylbismuth bis(chloroacetate) (TPBC), and triphenylbismuth bis(iodoacetate) (TPBI). To evaluate their suitability as EUV photoresist materials, we conducted E-beam lithography tests. Both TPBA and TPBF showed no response to E-beam exposure, while TPBC and TPBI exhibited promising photoresist behavior. In particular, TPBC required a minimum exposure dose of 150.1 μC/cm², and TPBI required only 90.3 μC/cm². This result suggests that as the halide size increases, the EUV absorption efficiency improves, leading to better performance as EUV photoresists. These findings provide valuable insights into the design of next-generation photoresist materials for semiconductor applications.
Bipolar Membrane Development and Applications: A Review
Authors: Black Julian , Song Qilei
Published: December 2024

Bipolar membranes (BPMs) are a versatile technology with the ability to drive water dissociation and ion transport, making them valuable for applications in energy storage, carbon capture, and water treatment. BPMs consist of a cation exchange membrane, an anion exchange membrane, and a catalyst layer between the two. This composite membrane enables water dissociation where an applied electric field can drive H+ and OH- ions out of the BPM in opposite directions. The pH gradient developed by the BPM’s water dissociation and ion transport enables chemical reactions that would otherwise require extreme conditions. BPMs can be used to operate the anode and cathode at a different pH, providing ideal conditions for electrocatalysts. This makes them a promising technology for electrolysers and fuel cells. BPMs are also being researched for use in CO2 capture and electrolysis. Current industrial uses include desalination, pH adjustment in water treatment, acid-base synthesis, and a variety of other applications where a pH gradient is required.

In this review poster we survey current research on BPMs, from materials development to fabrication techniques. We also discuss their current applications in industry and promising technologies utilising BPMs. We review the materials development for high performance BPMs, looking in particular at how catalysts and membranes are developed and can work together to efficiently transport ions and perform water dissociation. Different catalysts from literature are surveyed and compared by their water dissociation performance. The latest cation and anion exchange membranes with high ion conductivity, high permselectivity, and good stability are reviewed. Finally, we describe different methods of fabricating BPMs, including layer-by-layer assembly, solution casting, hot pressing, and electrospinning. We map out the current state of the art and discuss potential avenues for research, including the use of novel catalysts and membranes, and advanced fabrication techniques for improved efficiency.
Occurrences of per- and Polyfluoroalkyl Substances (PFAS) in the Environment and Their Oxidative Degradation By Modified Fenton Treatment
Authors: Walker Tasia
Published: December 2024

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This research examines the remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also evaluated, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants. Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This literature review examines the occurrence, health impacts, regulation, and remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also discussed, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants.