bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Development and on-Body Tests of Wearable Electrochemical Sensors Fabricated By Screen Printing
Authors: Shitanda Isao
Published: December 2024

We have developed a biofuel cell that uses environmentally and physically safe enzymes to generate electricity from sugar and lactate contained in body fluids. We have also developed a self-driven healthcare device that senses the components of body fluid based on the output value. We have studied the feasibility of a wearable healthcare device that does not require battery replacement, is thin and light, and does not feel uncomfortable to wear, such as for fatigue management of athletes and monitoring for heat stroke in mid-summer.

Development of various elemental technologies, evaluation technologies, and utilization technologies to enhance the practicality of biofuel cells was promoted, and the performance of biofuel cells as a whole was raised to the world's highest level.

In particular, we developed a diaper biofuel cell that generates electricity from urinary sugar in diapers to measure urinary sugar levels and a lactate biofuel cell that generates electricity from lactate in sweat to measure lactate levels.

We have also conducted research on lactate and ion sensors for on-body test. We have conducted implementation tests of self-driven lactate sensors, lactate sensors, ion sensors, and perspiration sensors on actual human wearers. A trend of correlation between blood lactate and sweat lactate has been observed through exercise using an aerobic bike. This presentation will highlight these results.
Characterization of Electrochemical Deposition of Aluminum from AlCl3-Urea DES with NaCl
Authors: Yoo BungUk , Lee Jun Young , Lee Jooyul , Seunghoe Choe , Lee Kyu Hwan
Published: December 2024

Non-aqueous electrolytes had a wider electrochemical window than aqueous electrolytes, allowing the plating of metals such as aluminum that could not otherwise be plated in aqueous solutions. Non-aqueous plating solutions include organic solvents, molten salts (MS), ionic liquids (IL), and deep eutectic solvents (DES). Of these, IL and DES exist in liquid form at room temperature and were less flammable and less volatile than organic solvents, making them suitable for replacing toxic organic solvents. However, DES was not suitable for plating process than IL due to its low conductivity. Therefore, in this study, to improve the conductivity of DES, NaCl was added to AlCl3-urea to improve the conductivity and aluminum was electrochemically electrodeposited. The synthesis of the solutions in various compositions with and without NaCl was carried out, and the electrochemical characterization of the synthesized solutions was performed. The conductivity improvement and plating efficiency improvement were confirmed by comparing the plating solution with and without NaCl addition, and the microstructure analysis of the electrodeposited aluminum under various applied current density conditions was performed.
Ni Nanoparticles in Functionalized Ionic Liquids for Chemoselective Hydrogenation Catalysis
Authors: Riisager Anders , Krishnan Deepthy , Schill Leonhard , Axet M. Rosa , Philippot Karine
Published: December 2024

The decomposition of organometallic Ni0 complexes with stabilizing agents - named the organometallic approach - is an attractive method to obtain size-controlled Ni nanoparticles (NPs) in solution. The method allows fine control of the NPs growth, while offering a clean metal surface due to the absence of byproducts formed from the precursor complex. Moreover, the nature of the stabilizer can be tuned to affect the catalytic properties of the Ni NPs [1].

Ionic liquids (ILs) can function as both stabilizers and dispersion media for the synthesis of small and narrow-sized Ni NPs by the organometallic approach under mild conditions [2]. Such systems can also benefit from the use of functionalized ILs (FILs) that can interact with the metallic surface and create ligand effects during catalysis [3]. Controlled oxidation forming Ni-NiO NPs is another approach to modify the catalytic reactivity, as previously shown for solid NiO catalysts [4].

In this work, well-defined Ni NPs were synthesized in different ILs (Ni/ILs) and exploited as catalysts for the chemoselective reduction of 2-cyclohexen-1-one, as a representative of the group of α,β-unsaturated carbonyl compounds with industrial relevance [5]. Interestingly, the Ni/ILs systems were found to be efficient catalysts for selective hydrogenation of the substrate to cyclohexanone using hydrogen gas with performance dependence on the applied ILs whereas the oxidized counterparts (Ni-NiO/ILs) were active and selective for catalytic transfer hydrogenation to 2-cyclohexen-1-ol with 2-propanol as H-source and solvent, both under mild reaction conditions (Figure 1).

The work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 860322.

[1] C. Amiens, D. Ciuculescu-Pradines, K. Philippot, Coord. Chem. Rev. 2016, 308, 409.

[2] M.H.G. Prechtl, P.S. Campbell, J.D. Scholten, G.B. Fraser, G. Machado, C.C. Santini, J. Dupont, Y. Chauvin, Nanoscale 2010, 2, 2601.

[3] D. Krishnan, L. Schill, M.R. Axet, K. Philippot, A. Riisager, Nanomater. 2023, 13, 1459.

[4] J. He, M.R. Nielsen, T.W. Hansen, S. Yang, A. Riisager, Catal. Sci. Technol. 2019, 9, 1289.

[5] D. Krishnan, L. Schill, M.R. Axet, K. Philippot, A. Riisager, ChemCatChem 2024, 16, e202301441.

Figure 1
(Invited) Surface and Interface Structure Control of Water Electrolysis Electrodes
Authors: Todoroki Naoto
Published: December 2024

The development of highly active and durable electrode for the oxygen evolution reaction (OER) is essential for efficient hydrogen production by polymer electrolyte membrane water electrolysis (PEMWE). Ir oxide is currently used as OER catalysts, while their extreme scarcity and high cost hinder the widespread adoption of PEMWE. Recently, Ru oxide has attracted attention as a non-iridium OER catalyst with high electronic conductivity. However, since its electrochemical stability under acidic environment is quite low compared to Ir oxide, significant stability improvement is needed for practical applications of Ru-oxide catalysts.

In this talk, I will present our recent work on surface and interface control to improve the performance of Ru oxide using single crystal thin film electrodes prepared by arc-plasma deposition. First, I will introduce the beneficial role of Ti doping on RuO2(hkl) surfaces (hkl = 110, 001, 100). The OER activity, stability, and corrosion resistance were enhanced by a small amount of Ti doping on all the hkl surfaces. Second, the importance of structural control of noble metal oxide catalyst/transition metal oxide support interface will be discussed. The SnO2 interlayer effectively improved not only the electronic resistance, but also the structural stability at the catalyst/support interface [1]. These studies demonstrate that metal oxide thin film model electrodes are powerful platforms to elucidate the role of surface and interfacial structure on the water electrolysis electrodes.

This study was partly supported by JSPS KAKENHI Grant Number 21H01661, 22K19078 and Toyota Mobility Foundation Hydrogen Initiative.

[1] N. Todoroki, R. Kudo, K. Hayashi, M. Yokoi, N. Naraki and T. Wadayama, ACS Catalysis, 13, 2023, 11433.
The Cooperative Effect of Iron Single Atoms on Palladium Catalyst for Electrochemical Oxidation Carbohydrazide
Authors: Wang Yaxin , Cui Liting , Tao Li , Lu Shanfu , Wang Haining , Zhang Jin
Published: December 2024

Carbohydrazide (CHZ) is attractive as a liquid fuel in fuel cells due to its high energy density and environment-friendly characteristic. Nevertheless, the sluggish kinetics of metal catalysts for the CHZ oxidation reaction (CHZOR) has hinder the wide application of the fuel. In the present work, transition metal single atom catalyst (MSA, M=Fe, Co and Ni) supported palladium nanoparticles (NPs) have been studied for the CHZOR. Distinct from the conventional active carbon supports, the MSA nanotubes play a bifunctional role by acting as the catalyst support and tuning the electronic structure of Pd NPs and simultaneously increasing the activity of Pd for CHZOR. Among them, Pd/FeSA shows the fast kinetics for CHZOR in terms of mass activity, specific activity and electron transfer number (Figure 1A). That is due to the stronger electron donation of Fe atoms to the Pd nanoparticles than other samples. Furthermore, density functional theory calculation and significantly emission of gases including CO2 and N2 in CHZOR from differential electrochemical mass spectrometer confirm that reaction mainly goes through the dehydrogenation of N-H bond and then cleavage of C-N bond with formation of N2 and COads at low potential and subsequent CO2 emission at high potential, while small amount of *N2H3 species undergo N-N bond cleavage accompanied with trace amount of NH3emission (Figure 1B).

Figure 1
(Invited) Morphology-Engineered Hematite for Addressing Short Hole-Diffusion Lengths
Authors: Jang Ji-Hyun
Published: December 2024

This study addresses challenges in photoelectrochemical (PEC) water oxidation on hematite photoanodes, with a focus on overcoming the limited hole diffusion length (~4 nm) and poor electrical properties. To achieve this, an efficient overlayer is integrated onto the branched structure, generating a highly porous architecture by leveraging additional reaction interfaces exploiting the Kirkendall effect. This phenomenon occurs during high-temperature annealing, particularly at the interface of the overlayer and Ti-FeOOH (hematite precursor), utilizing distinct diffusion rates of metal atoms. By introducing additional interfaces on the hematite precursor surface, porosity and pore size are effectively controlled, resulting in a highly nanoporous structure. Through morphological engineering, the overlayer facilitates heteroatom diffusion (doping) into the hematite lattice, thereby promoting facile charge transport. The overlayer material selection is guided by density functional theory calculations. The resulting optimized photoanode, combined with an efficient cocatalyst (NiFe(OH)x), exhibits a maximum photocurrent density of 5.1 mA cm-2 at 1.23 V vs. RHE, marking a 3.2-fold increase compared to the reference hematite photoanode. This enhancement is attributed to the highly nanoporous structure and optimal doping. Thus, this study represents a significant advancement in enhancing the PEC performance of hematite-based photoanodes for future applications.
(Invited) Transparent Conductive Porous Supports for Photoelectrochemical and Photocatalytic H2 Production
Authors: Sivula Kevin
Published: December 2024

Gas diffusion electrodes are essential components of common fuel and electrolysis cells that use gas phase reactants and products, but are typically made from graphitic carbon or metallic materials, which do not allow light transmittance, and thus limit the development of photoelectrode membrane assemblies for gas-phase solar fuel production. In this presentation, the application of solar H2 production from humid air is motivated and the simple and scalable preparation of transparent porous conductive substrates (TPCSs) using F-doped SnO2 (FTO) coated SiO2 interconnected fiber felt substrates is introduced. The resulting substrates have a porosity of 90 %, a roughness factor of 15.8 and a Young’s Modulus of 0.2 GPa. A sheet resistivity of 20 ± 3 Ω sq−1 and a loss of incident light of 41% at an illumination wavelength of 550 nm is found with FTO coating. The application of various semiconductors on the substrates was established including Fe2O3 (chemical bath deposition), BiVO4 (SILAR), CuSCN and Cu2O (electrodeposition), and semiconducting polymers (dip coating) and the liquid-phase photoelectrochemical performance commensurate with flat FTO substrates was confirmed. Gas phase H2 production was demonstrated with a polymer semiconductor photocathode membrane assembly at 1-Sun photocurrent density on the order of 1 mA cm–2 and Faradaic efficiency of 40%. Finally, the prospects for using the TPCSs as supports for photocatalysts are discussed.
Bias-Free Environmental Pollutants Conversion By Integrating Bi-Functional Catalyst with Dual Organic Photoelectrode System
Authors: Kim Yejoon , Lee Sanghan
Published: December 2024

The rapid increase in human activities has led to an oversupply of nitrate and glycerol, emerging as significant environmental pollutants, disrupting the delicate balance of the global nitrogen and carbon cycles. Addressing this challenge, photoelectrochemical (PEC) conversion harnesses solar energy to effectively convert excess nitrate into ammonia and surplus glycerol into high-value carbon compounds, thereby mitigating their environmental impact and enhancing both environmental sustainability and cost-effectiveness. Notably, among the resulting products, ammonia and formic acid have garnered attention as prominent carriers for hydrogen storage and transportation, given their high hydrogen storage capacity relative to their mass and volume, further emphasizing the importance of PEC conversion.

Organic semiconductor materials, characterized by high photovoltage and photocurrent density, present promising prospects for producing efficient photoelectrodes. However, their utility has been hindered by poor stability in aqueous electrolytes. In this study, we address this challenge by employing an encapsulation method to fabricate stable organic semiconductor-based photocathodes and photoanodes operable in aqueous electrolytes. Moreover, we have devised a novel photoelectrochemical system capable of operating without external voltage, facilitated by a dual photoelectrode system.

The Ni-Fe-P alloy, with its unique combination of bimetallic and phosphide properties, stands out as a promising non-noble metal catalyst. Nickel facilitates hydrogenation and enhances product selectivity, while iron boosts initial adsorption and reaction activity. Phosphorus disrupts electron distribution, creating additional active sites for intermediate adsorption. This multifaceted catalytic activity enables the Ni-Fe-P alloy to function effectively in both nitrate reduction and glycerol oxidation simultaneously.

By integrating a bifunctional Ni-Fe-P catalyst into our dual photoelectrode system, we've achieved significant progress. This system efficiently reduces nitrates and converts glycerol, yielding valuable hydrogen carriers like ammonia and formic acid. Importantly, we've attained photocurrent densities of several mA cm⁻² without the need for bias. This breakthrough marks a robust and effective development in photoelectrochemical systems, addressing both environmental remediation and hydrogen carrier production challenges.
(Invited) Operando Spectroscopic Analysis for Understanding Interfacial Photo/Electrocatalytic Processes
Authors: Kim Wooyul
Published: December 2024

Observing key intermediates directly on the catalyst surface poses a significant challenge in various photo/electrocatalytic processes, including CO2 reduction and O2 reduction reactions. To gain a comprehensive understanding of the reaction mechanisms, it is essential to conduct combined studies utilizing complementary tools such as electrochemical characterization, computational calculations, and operando spectroscopies. Among these, time-resolved attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) stands out as particularly suited for investigating electrochemical CO2RR due to its ability to observe interfacial processes in real-time with high surface sensitivity. Time-resolved analysis offered by ATR-SEIRAS allows for the exploration of the kinetic relevance of intermediates and their dynamics in relation to reactants and products during the reaction. Furthermore, integrating operando spectroscopic studies with material characterization enables the correlation of intermediate behavior with catalyst conditions. In this context, I will introduce in situ time-resolved FT-IR (or ATR mode) spectroscopic techniques to capture isotopically labeled products and key intermediates generated during the photoreduction of carbon dioxide.
(Invited) Paired Photoelectrochemical Conversion of CO2/H2o and Glycerol at High Rate
Authors: Janaky Csaba
Published: December 2024

Photoelectrochemistry holds the promise of directly converting sunlight to valuable chemical products since its birth over 50 years ago. Photoelectrochemical (PEC) methods, however, lag behind their electrochemical (EC) counterparts (which can be powered by a solar photovoltaic (PV) power source) in terms of current density, by orders of magnitude. In this work, we demonstrate that by integrating the recent achievements of the PV and EC communities (in terms of using concentrated sunlight and gas diffusion electrodes, respectively), we can achieve current densities similar to EC methods, but with lower energy input. Specifically, in this proof-of-concept study, we combined the direct PEC oxidation of glycerol (on a NiOOH co-catalyst-coated n-Si photoanode) with the dark hydrogen evolution (HER) or CO2 reduction (CO2R) in an anion exchange membrane (AEM) separated continuous-flow PEC cell. We achieved over 110 mA cm–2 photocurrent density under 10 Sun irradiation, which is at least an order of magnitude larger than those typically reported in the literature, for any of these PEC half reactions. We demonstrated that the product distribution of glycerol oxidation is notably different in PEC and EC scenarios at the same current density, and the parasitic oxygen evolution reaction (OER) can be suppressed in the PEC case. This approach raises new opportunities to drive electrochemical reactions with complex reaction pathways in a more selective manner even at high current densities. In the second part of my talk I will demonstrate the effect of the co-catalyst properties in tailoring the product distribution.
Au@Cu7S4/ZnS Ternary Yolk@Shell Nanostructures for Photocatalytic Hydrogen Production
Authors: Kuo Hsuan Hung , Fang Mei-Jing , Hsu Yung-Jung
Published: December 2024

Due to energy shortages and environmental issues, sustainable energy and clean fuels are widely researched and highly expected to serve as replacements to solve the problems. Photocatalytic hydrogen production is considered a green and economical approach from the viewpoint of sustainable energy and environment protection. However, photocatalytic hydrogen production suffers from a severe obstacle, which is low energy conversion efficiency, usually about 1% solar to hydrogen (STH) value, hindering it from commercialization. In order to solve the low-efficiency issue, preventing fast recombination of carriers and harvesting more photons from solar spectrum are two solutions to conquer the issue. In this work, we synthesized the Au@Cu7S4/ZnS ternary yolk@shell nanostructures and employed them as photocatalysts to conduct hydrogen production. The Au, Cu7S4, and ZnS were in direct contact, which can promote charge carrier separation. Furthermore, the ultraviolet region, visible region, and near-infrared region of the solar spectrum can be absorbed by bandgap absorption of ZnS and localized surface plasmon resonance of Au and Cu7S4, maximizing the harvesting of solar spectrum. In addition, the special yolk@shell nanostructure can enhance photocatalytic efficiency by endowing large surface area and promoting homogeneous reaction, accelerating mass transport kinetics. By finely adjusting the Cu and Zn ratio for Au@Cu7S4/ZnS, an optimal photocatalytic activity can be attained.
(Invited) Understanding Degradation Pathways during the Oxygen Evolution Reaction on Iridium-Based Electrocatalysts Via Liquid Phase Transmission Electron Microscopy
Authors: Moreno-Hernandez Ivan A.
Published: December 2024

The oxygen evolution reaction (OER) is a key reaction in several photocatalytic and photoelectrochemical reaction schemes. While iridium-based materials such as iridium dioxide are commonly used to catalyze the OER, contemporary findings indicate that iridium dioxide will undergo substantial corrosion during operation. A fundamental understanding of the degradation pathways during the OER is necessary to design materials that exhibit improved stability and enable the long-term operation of photocatalytic and photoelectrochemical devices. The Moreno-Hernandez Laboratory utilizes liquid phase transmission electron microscopy techniques that enable nanoscale and near-atomic spatial resolution imaging in liquid environments during electrocatalyst operation. These techniques were used to probe the stability of iridium dioxide nanocrystals and observe electrocatalyst degradation at near-atomic resolution for individual nanocrystals, and at nanoscale resolution for nanocrystal ensembles. Our observations indicate several reaction pathways and nanocrystal properties that were previously underexplored could have a substantial impact on the macroscale performance of iridium-based materials.
Determination of the Rate Change of Electrical Resistance of Aluminium Oxide Film By White Light-Optical Interferometry
Authors: Habib Khaled
Published: December 2024

A white light, i.e., Fabry-Perot, interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminum samples during the initial stage of anodization processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by Fabry-Perot interferometry, an electromagnetic method rather than an electronic method, the abrupt rate change of the resistance was called electrical resistance–emission spectroscopy. The anodization process of the aluminum samples was carried out by the DC method in different sulphuric acid concentrations (0.0,2,4,6,8,10% H2SO4) at room temperature. In the meantime, the Fabry-Perot interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the DC experiment for the aluminum samples in 0.0,2,4,6,8,10% H2SO4 solutions. The Fabry-Perot interferometry was based on a fiber-optic sensor in order to make real time-white light interferometry possible at the aluminum surfaces in the sulphuric acid solutions. The electrical resistance-emission spectra represent a detailed picture of not only the rate change of the electrical resistance throughout the anodization processes but also the spectra represent the rate change of the growth of the oxide films on the aluminum samples in different solutions. As a result, a new spectrometer was developed based on the combination of the Fabry-Perot, i.e., white light, interferometry and DC method for studying in situ the electrochemical behavior of metals in aqueous solutions. In addition, the obtained values of the resistance of the combination of the Fabry-Perot interferometry and DC method were compared with resistance values of the aluminum samples in 0.0,2,4,6,8,10% H2SO4 solutions by the electrochemical impedance spectroscopy (EIS).

Keywords: Fabry-Perot interferometry, White light interferometry, Electrical resistance, Anodization, Fiber-optics sensor, DC method & EIS.

Figure 1
(Invited) Well-Defined Electrocatalysis
Authors: Fairhurst Alasdair , Lim Chaewon , Ransom Benjamin , Haering Dominik , Stamenkovic Vojislav
Published: December 2024

Electrochemical energy conversion hydrogen technologies, such as fuel cells and electrolyzers have evolved as a prevailing option in achieving environmentally neutral energy and transportation sectors. Global deployment calls for improved performance of employed materials that are mainly based on scarce elements. Research aimed towards the design and synthesis of materials with advanced electrochemical properties, while diminishing the need for rare constituents, will be presented. Emphasis will be placed on the fundamental understanding of well-defined electrified interfaces and resolving their functionality at atomic and molecular scale. The research strategy is built on insights at the atomic/molecular level that define events controlled by electrode potential, which triggers electron and ion transfers across the electrochemical interfaces. The role of structure, spatial arrangement and nature of the surface atoms will be discussed for different reactive species, spectators, and impurities.
A Carbon-Efficient Bicarbonate Electrolyzer
Authors: Zhang Zhen , Li Ju
Published: December 2024

Carbon efficiency is one of the most pressing problems of carbon dioxide electroreduction today. While there have been studies on anion exchange membrane electrolyzers with carbon dioxide (gas) and bipolar membrane electrolyzers with bicarbonate (aqueous) feedstocks, both suffer from low carbon efficiency. In anion exchange membrane electrolyzers, this is due to carbonate anion crossover, whereas in bipolar membrane electrolyzers, the exsolution of carbon dioxide (gas) from the bicarbonate solution is the culprit. Here, we first elucidate the root cause of the low carbon efficiency of liquid bicarbonate electrolyzers with thermodynamic calculation and then achieve carbon-efficient carbon dioxide electroreduction by adopting a near-neutral-pH cation exchange membrane, a glass fiber intermediate layer, and carbon dioxide (gas) partial pressure management. We convert highly concentrated bicarbonate solution to solid formate fuel with a yield (carbon efficiency) of greater than 96%. A device test is demonstrated at 100 mA cm-2 with a full-cell voltage of 3.1 V for over 200 h [1].

Reference:

[1] Zhang et al., A carbon-efficient bicarbonate electrolyzer, Cell Rep. Phys. Sci.
4, 101662 (2023).
Electrocatalytic Reduction of Simulated Industrial CO2 and CO Mixtures: Revising Chronoamperometry to Enable Selective Gas Mixture Reduction via Cyclic Voltammetry
Authors: Lisak Grzegorz , Chen Wen Qian , Loong Cyrus Foo Jit , Ge Liya , Veksha Andrei , Chan Wei Ping , Shen Yafei
Published: December 2024

The reduction of carbon oxide mixtures remains underexplored despite advances in the electrocatalytic reduction of pure CO2 or CO. A novel approach for the electrocatalytic reduction of carbon oxide mixtures was developed and optimized through the controlled application of cyclic voltammetry (CV). This method, serving as an alternative to conventional chronoamperometry, ensures a continuous reduction reaction by cycling between the optimized reduction potentials of CO2 (−1.4 V) and CO (−1.6 V). The approach resulted in a significant increase in production efficiency, ranging from 25% to 40% for predominant products (HCOOH and C2H4).

The methodology involved the use of CV to conduct reduction reactions within a defined negative potential window, ensuring a continuous reduction process throughout the entire cycling. This led to an enhanced performance, dependent on the scan rate of cycling, revealing plausible correlations with mass transfer and electrode surface dynamics. Furthermore, the findings indicated that the selectivity towards HCOOH and C2H4 is closely related to the CO2/CO ratios of gas sources, providing insight into the potential for modulating selectivity of industrial gas reduction for improved product quality and customization.

This novel approach of electrocatalytic reduction of carbon oxide mixtures proves to have high universality and potential for industrial applications. The method not only achieves increased efficiency in the production of key products but also offers the ability to modulate selectivity based on gas source ratios. This research provides a new perspective for improved product efficiency and customization in industrial gas reduction processes, making it highly valuable for development of green and renewable energy technologies.

Ref.

[1] W.Q. Chen, J.L.C. Foo, L.Y. Ge, A. Veksha, W.-P. Chan, Y. Shen, G. Lisak, Electrocatalytic reduction of simulated industrial CO2 and CO mixtures: Revising chronoamperometry to enable selective gas mixture reduction via cyclic voltammetry, Chemical Engineering Journal 487 (2024) 150602.

Figure 1
Enhancing Electrochemical Reactive Capture of CO2 for Improved Efficiency of Desired Carbon Products
Authors: Ynzunza Jenna
Published: December 2024

Modern society’s existence hinges on the utilization of chemicals and fuels predominately produced from fossil fuels. Though fossil fuels are of the utmost importance for the chemical industry and stabilizing our energy grid, they are the main cause of increased CO2 in the atmosphere leading to rising global temperatures. Technologies currently employed to reduce net emissions are carbon capture and electrochemical CO2 conversion. Though these two methods have been explored in isolation, only recently have they attracted interest as an integrated technology, otherwise known as Reactive Capture of Carbon dioxide (RCC). While these technologies have well-established techniques and methods, they are for the most part non-transferable to RCC, leading to a demand for designing RCC specific systems.One specific approach within the RCC uses amines enriched with CO2, containing less free CO2 gas, and fed into an electrolyzer.These captured CO2-adducts have an intrinsically different kinetic pathway compared to aqueous ECR. Recent results on monometallic post-transition metal catalysts (Sn, In, Bi) shows an increase in hydrogen evolution reaction (HER), a competing reaction for ECR. The facile kinetics of HER dominates in aqueous environments and now under RCC conditions. This leads to the question of whether ECR activity descriptors, or quantitative property descriptors that influence catalyst reactions, can translate to RCC. Electrochemical experiments will be performed on monometallic metals (Sn, Bi, In), within a flow cell reactor for increased mass transport. The capture sorbents, primary and secondary alkanolamines, are studied under pulse electrolysis to tune product distribution away from HER and favor ECR products. The double layer constitutes a charged boundary layer where ions in electrolyte align themselves at the solid interface to neutralize surplus charge on the metal. Electrolysis is performed at millisecond pulses to control favorable reaction intermediates, such as *OCHO and *CO, directing selectivity towards formic acid and carbon monoxide. Catalyst activity is understood from electrochemical analytical techniques as well as full product distribution and catalyst characterization.
VOC Detection Using p-Type Sm(Fe,Co)O3 Perovskite Oxides
Authors: Itagaki Yoshiteru , Mori Masami , Joutsuka Tatsuya , Aono Hiromichi
Published: December 2024

In recent years, there has been concern about the resurgence of sick house syndrome caused by volatile organic compounds (VOCs) emitted from building materials, and there is an urgent need to develop sensors that can continuously detect VOCs with high sensitivity. Our research group is conducting research on VOC detection characteristics using SmFeO3. SmFeO3 is a p-type semiconductor with a perovskite crystal structure and has high oxidation activity against VOCs. However, SmFeO3 has high electrical resistance in air, and sensors using SmFeO3 require heating to a measurable resistance range (approximately 300°C or higher), and also require a measurement system with high input impedance. For this reason, a high cost for apparatus and high power consumption are issues for practical application. Therefore, in this study, we focused on SmFe1-xCoxO3 as the sensing electrode material to operate sensors at reduced temperature. Since SmFeO3 is a p-type semiconductor, Co substitution or hole doping is expected to increase electrical conductivity, and a good redox property of cobalt ion may enhance catalytic activity of VOC decomposition. Regarding the oxidation activity of SmFe1-xCoxO3 powder, the oxidation activity against toluene increased with increasing Co content. T50 = 210oC (x=0), 205 oC (x=0.1), 155 oC (x=0.3), 165 oC (x=0.5). The oxidation activity for ethanol also increased with the amount of substitution, T50 =130oC (x=0), 110 oC (x=0.1), 85 oC (x=0.3), 75 oC (x=0.5). The temperature at which the maximum response value of each sensor was shown is 300℃ (x=0), 250℃ (x=0.1), 250℃(x=0.3), and 200oC (x=0.5). It was found that the Co substitution effectively reduce operating temperature. The response value (RVOC/Rair) in ethanol was results in S=4.6 (x=0 at 300oC), S=6.4 (x=0.1 at 250oC) and the sensor with x=0.1 increased sensor response at reduced temperature. The increase in the response value is thought to be because the sensor with x=0.1 has a higher oxidation activity at 250 oC than that with x=0 at 300 oC, The response of the sensors followed the power law, S=aPVOC
n. Here, a and n are constants, and PVOC is the partial pressure of the gas. The constants a and n were determined from the equation log(S)=log(a)+nlog(PVOC), and the response value to 0.1 ppm ethanol was predicted as S=1.11 (x=0), 1.88 (x=0.1), 1.88 (x=0.3), and 1.94 (x=0.5), and it was expected that the response values at 0.1 ppm would increase due to cobalt substitution. Sensor properties mainly depend on material properties and sensor structure (sensing membrane structure). Therefore, it is suggested that higher sensitivity can be achieved by optimizing the sensor structure in the future, and it is considered that the use of cobalt substitutes as a sensor material is useful from the viewpoint of sensitivity.
Grain Boundary Passivation of Wide Bandgap Perovskites using Inorganic Potassium Lead Halides for Tandem Solar Cells
Authors: Kim Sunwoo , Yun Yeonghun , Vidyasagar Devthade , Im Doyun , Lee Sangwook
Published: December 2024

Wide bandgap (WBG) perovskite solar cells (PSCs) are a crucial component in advancing perovskite-based tandem solar cells for absorbing high-energy photons. However, increasing Br to I ratio in WBG perovskites decreases the formation energy, leading to rapid crystallization and small grain size. Consequently, the numerous grain boundaries are formed with charged defects such as vacancies, interstitials, and undercoordinated ions, leading to large open circuit voltage (V
OC) deficits and severe halide segregation under continuous light illumination. Therefore, passivating grain boundary defects is essential for achieving high V
OC and enhanced stability. Here, we introduce an effective strategy to passivate the grain boundaries with an inorganic protective layer as well as to reduce the density of grain boundaries on perovskite film, by incorporating potassium thiocyanate (KSCN) into I-Br mixed halide WBG perovskites. The incorporation of KSCN into the mixed halide forms band-shaped barriers on the film along the grain boundaries. Meanwhile, the KSCN enlarges the grains of the mixed halide film, which is attributed to the effect of SCN ions, as is well-known. The incorporation of potassium thiocyanate dramatically increases the fill factor and V
OC of WBG (1.82 eV) single junction PSCs owing to reduced trap density, achieving a high power conversion efficiency of 18.02%. Furthermore, both operational and shelf stability are improved with retarded light-induced halide segregation. Using the passivated WBG sub-cells, monolithic all-perovskite tandem solar cells are demonstrated.
Characterization and Electrochemical Performance of Na(Ni,Fe,Mn)O2 for Sodium-Ion Battery Cathodes
Authors: Kang Min-Seung , Young-guk Son , Jeong Il-Kyoung , Cho chae-Ryong
Published: December 2024

Given the escalating demand for sustainable energy storage solutions, sodium-ion batteries (SIBs) have emerged as formidable contenders against lithium-ion batteries (LIBs), capitalizing on the abundant and cost-effective nature of sodium resources. A pivotal determinant in advancing SIB technology lies in the quest for efficient anode materials, which significantly influence the overall performance and stability of the battery system. Among potential candidates, Na(Ni,Fe,Mn)O2, a layered transition metal oxide, holds promise as an anode material for SIBs.

To explore this potential, we employed the solid-state reaction method to synthesize and analyze three novel anode materials: NaNiO2, NaNi0.9Fe0.05Mn0.05O2, and NaNi0.8Fe0.1Mn0.1O2. Stoichiometric proportions of Na2O2, NiO, Fe2O3, and Mn2O3 served as the starting materials, supplemented with an additional 15% Na2O2 to ensure thorough decomposition during synthesis.

Following synthesis, we conducted a series of analyses to elucidate the structural characteristics of the materials. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to confirm the basic surface morphology, crystal structure, and phase composition. X-ray photoelectron spectroscopy (XPS) analysis provided insights into the elemental composition and chemical states.

Further investigation into the nanostructure and electrochemical performance was carried out using transmission electron microscopy (TEM) and in-situ XRD. TEM analysis revealed crystal defects, interface structures, and nanoparticle morphology, while in-situ XRD allowed for real-time observation of crystal structural changes during cycling.

Subsequently, the synthesized materials were utilized as active materials to fabricate Half Coincells, with sodium metal serving as the cathode. Electrochemical evaluations, including constant current charge-discharge tests at various current densities and rate performance assessments, were conducted. These evaluations enabled us to assess the specific capacity, rate capability, and cycling stability of each material, facilitating a comparative analysis of their suitability as anode materials for SIBs.

In summary, this study employs a comprehensive analytical framework to explore the structural characteristics and electrochemical behavior of Na(Ni,Fe,Mn)O2 for SIB applications. By integrating advanced characterization techniques with electrochemical measurements, we aim to uncover key insights into its potential as a high-performance cathode material, advancing the development of sustainable energy storage technologies.

This research was supported by the NRF funded by the MSIT and MEST (grant numbers NRF-2021R1A4A1022198, NRF-2022R1A2B5B01001943, and NRF-2018R1A5A1025594).

Figure 1
Investigating the Characteristics of Pulverized Coal Combustion Using Ansys Fluent: A CFD Study of a 300 kW Swirl Burner
Authors: Lertanan Thanaporn , Podjanasatja Visaruta , Chuchan Donlaya , Sukjai Yanin
Published: December 2024

Although the global focus is shifting towards clean energy to replace coal, an immediate technological transition is not yet feasible due to the widespread prevalence of the existing coal combustion technology. The main objective of the present work is to investigate the characteristics of pulverized coal combustion by using Ansys Fluent. This study describes the fluid flow and combustion reactions in the 2D axisymmetric computational fluid dynamics (CFD) model for the 300 kW cylindrical swirl pulverized coal burner. The study was conducted to analyze the combustion process including the volatilization and char combustion models, while varying the ratio of air inlet velocity, and examining the effect of swirl number on pulverized coal combustion. The numerical modeling results for burner′s operating conditions are validated with the steady‐state temperature measurement in the burner. The significant outcome of the associated parameters found that the flame in the burner formed a spiral before converging into the flame line in the main combustion chamber. As a result, increasing the primary airflow rate led to a decrease in the axial temperature in the preliminary combustion chamber and decreasing the primary airflow showed the highest temperature in all three cases. While the secondary airflow increases, the swirling flow will be induced inside the chamber, which affects the highest temperature profile in the preliminary combustion chamber. Changing the tertiary airflow rate did not significantly affect the combustion. However, increasing the tertiary airflow rate improved the completeness of combustion. The swirl numbers also influenced the phenomena of combustion, the volatile released, and combustion reactions which could occur more rapidly with a higher swirl number due to a higher concentration of vortex region. Similarly, the highest swirl numbers resulted in the lowest excess O2 at the exit and the least amount of CO formation.
A Hyperchaotic Lorenz and DNA‐Encoded Image Encryption Algorithm
Authors: Li Shuangyuan , Li Mengfan
Published: December 2024

In order to solve the problem that images are easy to leak and tamper during transmission and enhance the safety of image encryption, an image encryption algorithm based on deoxyribonucleic acid (DNA) coding and hyperchaotic Lorenz system is proposed. First, the hyperchaotic Lorenz system is proposed to replace the traditional logistic mapping algorithm so that the mapping range of the chaotic sequence reaches surjection, and the hyperchaotic Lorenz system is discretized using the fourth‐order Runge–Kutta algorithm. The generated chaotic sequence is encoded according to DNA coding rules, and the encoded image is encrypted and scrambled by using the index of chaotic sequence. Finally, DNA algorithm rules are used for diffusion processing to obtain the ciphertext image. Key space analysis, histogram analysis, correlation analysis of adjacent pixels, and information entropy analysis of the algorithm results are performed. Meanwhile, the mean square error (MSE) of pepper and salt noise density is analyzed by the peak signal‐to‐noise ratio (PSNR). It shows that the algorithm can resist various external attacks and has high security.
Predictors for Sedation Failure in Mitral Transcatheter Edge‐to‐Edge Repair Procedures
Authors: Frerker Christian , Mathern Malte , Saraei Roza , Marquetand Christoph , Graf Tobias , Alhagi Mulham , Stiermaier Thomas , Genske Florian , Jurczyk Dominik , Rawish Elias , Dejanovikj Momir , Foth Friederike , Eitel Ingo , Schmidt Tobias
Published: December 2024

Background: Mitral transcatheter‐edge‐to‐edge‐repair (M‐TEER) is mostly done with using general anesthesia (GA). Limited data including specific risk factors exist for a deep sedation (DS) approach.

Methods and Results: 464 M‐TEER procedures were included for comparison of a DS approach versus those who required a conversion to GA. Specific predefined risk factors were analyzed to identify those patients who might not benefit from a DS strategy by the need of conversion to GA. The conversion rate from DS to GA was 6.7% (n = 433 successful DS and n = 31 conversion to GA). Mean age was 80 years. Classical surgical risk scores did not show any significant difference between the two groups. Patients with DS had a higher procedural success rate (96.1% versus 80.1%; p < 0.001). The time on the intensive care unit (ICU) (3.9 h versus 126 h; p = 0.023) was shorter for patients with DS. Patients who were in the need for a conversion to GA had a lower 30‐day and 1‐year survival rate. A multivariate analysis for conversion to GA showed body mass index (p = 0.023), pre‐existing kidney failure (p < 0.001), obstructive sleep apnea syndrome (OSAS) (p = 0.031), systolic pulmonary pressure value (p = 0.013), and concomitant tricuspid regurgitation (p = 0.049) as risk factors.

Conclusions: Using DS in M‐TEER is feasible with a low conversion rate to GA. In case of a conversion, the procedure is less successful regarding reduction of MR and more complications occurred with a lower survival rate up to 12 months. These data suggest that conversion from DS to GA is high risk. Therefore, we could identify different predictors for the need of a conversion to GA. However, our results could only be hypothesis‐generated and should be evaluated in a randomized study.
An Overview of the Biological Complexity of Vitiligo
Authors: Matarrese Paola , Puglisi Rossella , Mattia Gianfranco , Samela Tonia , Abeni Damiano , Malorni Walter
Published: December 2024

Vitiligo is a skin disease that affects all ethnicities and genders and is characterized by the loss of pigment essentially due to the selective loss of melanocytes. Although it is generally considered a systemic disease associated with polymorphisms in genes involved in the immune response, vitiligo is also considered an oxidative imbalance‐associated disease. It represents a multifactorial pathology in which some genetic predisposition and epigenetic factors coupled with some critical biochemical and molecular pathways could play a pivotal role. The aim of this work was thus to review some of the fine cellular mechanisms involved in the etiopathogenesis of vitiligo, mainly focusing on the nonimmunological ones, extensively highlighted elsewhere. We took into consideration, in addition to oxidative stress, both the cause and the hallmark of the pathology, some less investigated aspects such as the role of epigenetic factors, e.g., microRNAs, of receptors of catecholamines, and the more recently recognized role of the mitochondria. Sex differences associated with vitiligo have also been investigated starting from sex hormones and the receptors through which they exert their influence. From literature analysis, a picture seems to emerge in which vitiligo can be considered not just a melanocyte‐affecting disease but a systemic pathology that compromises the homeostasis of a complex tissue such as the skin, in which different cell types reside playing multifaceted physiological roles for the entire organism. The exact sequence of cellular and subcellular events associated with vitiligo is still a matter of debate. However, the knowledge of the individual biological factors implicated in vitiligo could help physicians to highlight useful innovative markers of progression and provide, in the long run, new targets for more tailored treatments based on individual manifestations of the disease.
Differential DNA Methylation in the Benign and Cancerous Prostate Tissue of African American and European American Men
Authors: Chernoff Meytal , Demanelis Kathryn , Gillard Marc , Delgado Dayana , Gleason Kevin J. , Oliva Meritxell , Chen Lin , Williams Anthony , Szmulewitz Russel Z. , Vander Griend Donald J. , Pierce Brandon L.
Published: December 2024

Background:

African American (AA) men are at increased risk of prostate cancer compared with European American (EA) men. Biological mechanisms, including epigenetics, likely contribute to this disparity, but prior studies have been limited by sample size, candidate gene approaches, or lack of epigenome-wide DNA methylation (DNAm) data.

Methods:

To improve our understanding of these mechanisms, we compared DNAm features distinguishing tumor and paired histologically benign tissue from 76 AA and 75 EA patients with prostate cancer. We generated genome-wide array-based DNAm data and conducted differential methylation analyses comparing tumor and benign tissues in each ancestry group. We then examined the predictive ability of our identified sites and differential methylation by ancestry group.

Results:

We identified 90,747 and 98,929 differentially methylated CpGs in AA and EA, respectively, with 76,400 common to both groups. We identified 6,267 genes with differentially methylated promoters common to both ancestries and 639 and 1,301 genes unique to AA and EA respectively, as well as differentially methylated pathways. Only 10 CpGs were needed to distinguish tumor from benign based on a receiver operating characteristic curve (AUC > 0.9), with differentially methylated CpGs in one ancestry accurately predicting tumor versus benign in the other group. We also identified ancestry-associated CpGs (89 in tumor, 423 in benign).

Conclusions:

Methylation features distinguishing tumor and benign were similar for EA and AA men; however, subtle differences were identified.

Impact:

Differences in tumor and ancestry-associated CpGs may reveal differential tumor growth strategies, an important area for future disparities research.