bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the Impedance of an Iron/Iron Redox Flow Battery at Different State of Charge Conditions – a Distribution of Relaxation Times Analysis
Authors: Challuri Sai Venkata Akhil Kumar , Noack Jens 
Published: February 2024

New energy storage technologies are needed to offset the erratic power supply of renewable energy sources due to the rising global energy demand and the urgency of climate change action. The Iron/Iron redox flow battery is a viable contender for large-scale energy storage, even if there are still issues with operational parameters and efficiency. Due to the positive electrode's moderate pH and low voltage, which preserves minimum toxicity and aggressivity, iron is a very affordable active material, making it feasible to develop inexpensive energy storage systems and batteries. The Electrochemical impedance spectroscopy technique was utilized to understand the degradation of the iron/iron redox flow battery during charging and discharging operation modes. However, discriminating between processes occurring at similar time scales is difficult since they overlap in the generally used Nyquist or Bode representation. Distribution of relaxation times (DRT) analysis tackles this issue by converting the EIS data with respect to the time constants of the individual processes. Individual processes such as electrochemical reactions inside the iron/iron redox flow cell, transport processes through porous structures, and iron ion transport were investigated.
The impedance measurements were carried out to evaluate the ohmic resistance during the charging and discharging phases of the iron/iron redox flow battery with varied states of charge ranging from 0-100% while charging and 100-0% while discharging. In this series, a DC offset load of 100 mA in the charging and discharging directions was used to test the resistance differential associated with the battery's state of charge. In the charging phase of the battery of three DC offset load parameters, the iron ions were transported faster in the process while the state of charge of a battery increased at lower frequencies. The impedance increased when the state of charge decreased at a higher frequency range, involving the iron ions transported through the negative half-cell in an iron/iron redox flow battery. The overall ohmic resistance in the charging phase of the battery decreased up to 6 % until the battery was fully charged, but in discharging phase, the overall ohmic resistance increased to 2 %. This indicated that the DC offset load in the charging and discharging direction were dependent on the battery's state of charge.

Figure 1
Realization High-Voltage Stabilization of O3-Type Layered Oxide Cathodes for Sodium-Ion Batteries by Sn Simultaneously Dual Modification
Authors: Song Tengfei , Chen Lin , Gastol Dominika , DONG Bo , Marco José F , Berry Frank J , Slater Peter R. , Reed Daniel , Kendrick Emma 
Published: February 2024

The total global production of lithium-ion batteries (LIBs) used in electric vehicles and stationary energy storage devices has increased sharply to reach the targeted Net Zero by 2050. This leads to concerns about the future and long-term availability and cost of critical raw materials (cobalt, nickel, lithium and copper) employed in LIBs. Therefore, alternative new-generation batteries with comparable performance but using less critical raw materials are needed.
Sodium-ion Batteries (NIBs) offer a wealth of possibilities for inexpensive and sustainable energy storage devices. To maximize their potential, new cathode materials with high energy densities and stable structures are required. Cobalt-free sodium transition metal oxides of O3 type are a predominant cathode for NIBs due to their appreciable specific capacity, reduction in the use of critical elements, and the potential to rival LiFePO4 in terms of energy density. However, rapid capacity fading caused by serious structural and interfacial degradation hamper this process.
Herein, we provide a novel Sn-modified O3-type NaNi1/3Fe1/3Mn1/3O2 cathode with improved high-voltage stability by bulk Sn doping and surface coating simultaneously. The bulk substitution of Sn4+ stabilizes the crystal structure by alleviating the irreversible high voltage phase transition and lattice structure degradation. In the meantime, the spontaneously formed tin rich surface layer effectively inhibits surface parasitic reactions and improves interfacial stability during cycling. As a result, the Sn-modified NaNi1/3Fe1/3Mn1/3O2 cathode exhibited excellent cycling performance by an almost doubled capacity retention increase after 200 cycles within 2.0-4.1V. The influence of Sn modification on the crystal structure and electrochemical properties has been investigated for the first time, and the mechanism was studied through an extensive analysis by in situ XRD, HRTEM, FIB-SEM, XPS and Mössbauer spectroscopy.
This work offers an industrially feasible strategy to simultaneously stabilize the bulk structure and interface for O3-type layered cathodes for SIBs and raises the possibility of similar effective strategies to be employed for other energy storage materials

Figure 1
The Effect of Oxygen Vacancies on Oxygen Evolution: The Case of BiVO_4
Authors: Österbacka Nicklas , Ouhbi Hassan , Wiktor Julia , Ambrosio Francesco 
Published: February 2024

Bismuth vanadate, BiVO4, is one of the most promising photoanode materials for the challenging oxygen evolution half-reaction in solar-driven water splitting. The material tends to be rich in oxygen vacancies, which strongly affects its photoelectrochemical properties. Experimental evidence suggests that oxygen deficiency is beneficial for the oxygen evolution reaction in the material, but the mechanism behind this enhancement is still controversial. The defects could be involved directly in the reaction if present at the surface, and the occupancy of the defect states could also play an important role. The latter is seldom considered in mechanistic studies, however.
Using density functional theory, we show that the surface oxygen vacancy in bismuth vanadate is stablest when fully ionized. We investigate how this affects the oxygen evolution mechanism by mapping out the stablest reaction intermediates and compare the resulting pathway with those on the unionized oxygen-deficient surface as well as the defect-free material. The overpotentials required to drive the reaction in each case are computed to quantify whether or not vacancy formation, and subsequent ionization, improves the thermodynamics of oxygen evolution.
Strategies for Sustainable Fuel Production Via Photoelectrochemical Synthesis
Authors: Im Sejin , Lim Yoongu , Surendran Subramani , Sim Uk 
Published: February 2024

Developing sustainable energy is highly imperative for humankind owing to the drastic rise in world population and the proportional rise in energy demand at the expense of energy consumption. Various efforts have been made to explore, generate, store, and utilize renewable energy to replace fossil fuels. Among them, solar energy is considered an alternative to fossil fuels because it is inexhaustible, clean, cost-effective, and versatile. Interestingly, this prime source provides massive energy that is high enough (1.9 × 108 TWh/yr) to counterattack global energy consumption (1.3 × 105 TWh/yr).
Photoelectrochemistry has been considered a promising route to harness this incredible energy by producing sustainable energy fuels and carriers such as hydrogen, hydrocarbon, and ammonia. PEC systems have the great advantages of simple process steps and very low environmental burdens. However, this technology must overcome many challenges regarding commercial applications, particularly in fabricating electrode materials for PEC water splitting.
One of the most important challenges to overcome this problem is discovering efficient catalysts for implementing photoelectrochemical (PEC) fuel production. A critical requirement for outstanding catalysts is an ability to boost the kinetics of a chemical reaction and durability against electrochemical and photo-induced degradation. Moreover, the charge-separation and transfer mechanism are the two paramount properties to consider while designing photoelectrodes. Briefly, the semiconductor materials to be used in PEC water splitting must possess a conduction band potential more negative than the reduction edge of hydrogen and a valence band potential positive to actuate water oxidation. In practice, the photocurrent density and solar-to-hydrogen (STH) efficiency of the n-type semiconductors are far behind the theoretical values.
To address this critical and long-standing technical barrier, I have focused on an intense search for efficient, durable, and inexpensive alternative catalysts with moderate band gap, efficient charge excitation-separation property, and high solar energy conversion efficiency for photoelectrochemical systems of water splitting, hydrocarbon conversion, and ammonia production.

Keywords

: Photoelectrochemistry, Sustainable Energy, Water Splitting, Ammonia synthesis, Urea synthesis, Hydrocarbon
A Urea Modified Ternary Aqueous Electrolyte with Tuned Intermolecular Interactions and Confined Water Activity for Highly Stable Zinc-Ion Batteries
Authors: Wang Ziqing , Mullins Charles Buddie 
Published: February 2024

Aqueous zinc-ion batteries (ZIBs) have gained attention as potential energy storage devices due to their high safety.1 However, the narrow electrochemical window and unfavorable side reactions (i.e., hydrogen and oxygen evolution reactions) induced by water decomposition restrict their development.2,3 Thus, constraining water activity is necessary to enhance stability and enlarge electrochemical window. In this study, we prepare a 2.9 m (mol kgsolvent
−1) Zn(ClO4)2−CO(NH2)2−H2O ternary aqueous electrolyte with restricted water activity at room temperature. Raman, Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) characterization techniques suggest strong intermolecular interactions between CO(NH2)2 and H2O, which decrease the free H2O molecules and reduce their associated activity to suppress the parasitic reactions at the electrodes. Density functional theory (DFT) calculations substantiate the strong hydrogen bonds between urea and water. Compared with eutectic electrolyte and water-in-salt electrolyte, this aqueous electrolyte exhibits a high ionic conductivity (6.83 mS cm−1) as conventional aqueous electrolytes without sacrificing the voltage window (2.5 V). Furthermore, DFT computations reveal the preferential adsorption of urea molecules onto the zinc surface, mediating zinc deposition process. The reduction of urea generates a robust organic solid electrolyte interphase (SEI), promoting homogeneous zinc deposition on the anode and hindering parasitic reactions. Consequently, this ternary aqueous electrolyte not only imparts Zn/Zn symmetric cells with prolonged cycling stability exceeding 1000 h at various current densities but also endows zinc−vanadium batteries a capacity of 250 mAh g−1 for 400 cycles at 1 A g−1. This finding highlights a promising approach for the development of stable aqueous zinc-ion batteries with an expanded electrochemical window.
Reference

A. Konarov et al. ACS Energy Letters
2018, 3 (10), 2620–2640.

C. Li et al. Joule
2022, 6 (8), 1733–1738.

J. Zhou et al. Advanced Materials
2021, 33 (33), 2101649.

Figure 1
Metastable Ni(I)-TiO2-X Photocatalyst: Self-Amplifying H2 Evolution from Plain Water without Noble Metal Co-Catalyst and Sacrificial Agent
Authors: Altomare Marco , Qin Shanshan , Saveleva Viktoriia A. , Badura Zdenek , Tomanec Ondrej , Mazare Anca , Zoppellaro Giorgio , Vertova Alberto , Taglietti Angelo , Minguzzi Alessandro , Ghigna Paolo , Schmuki Patrik 
Published: February 2024

This contribution describes the self-assembling and self-activating nature of a TiO2 photocatalyst that generates hydrogen from water in the absence of sacrificial species or noble metal co-catalysts [1]. Such system forms when nanoparticles of reduced anatase TiO2 are illuminated in an aqueous Ni2+ solution [2,3]. UV illumination creates in-situ a Ni+/TiO2/Ti3+ photocatalyst that over time produces H2 at a higher rate. Thus, UV light is both the synthesis tool that forms this active metastable photocatalytic entity and the energy provider for this entity to enable H2 evolution from water.
Operando X-ray absorption (XAS) and electron paramagnetic (EPR) spectroscopies show that key to self-assembly and self-activation is the light-induced formation of defects in the semiconductor [4], which enables the formation of monovalent Ni+ surface states. Metallic nickel states, i.e., Ni0, do not form, neither in the dark (resting state) nor under illumination (active state). Once the catalyst is assembled, the Ni+ surface states act as electron relay for electron transfer to form H2 from water.
Self-amplifying reaction schemes of this type entail considerable potential for developing a new generation of photocatalysts via simple one-pot synthesis routes.
References
[1] M. Altomare, S. Qin, V.A. Saveleva, Z. Badura, O. Tomanec, G. Zoppellaro, A. Vertova, A. Taglietti, A. Minguzzi, P. Ghigna, P. Schmuki, under review.
[2] S. Qin, Z. Badura, N. Denisov, O. Tomanec, S. Mohajernia, N. Liu, S. Kment, G. Zoppellaro, P. Schmuki, Electrochem. Commun. 122 (2021) 106909.
[3] A. Naldoni, M. Altomare, G. Zoppellaro, N. Liu, Š. Kment, R. Zbořil, P. Schmuki, ACS Catal. 9 (2019) 345–364.
[4] E. Wierzbicka, X. Zhou, N. Denisov, J.E. Yoo, D. Fehn, N. Liu, K. Meyer, P. Schmuki, ChemSusChem. 12 (2019) 1900–1905.
Core-Shell and Yolk-Shell Nanocrystals for Hydrogen Production
Authors: Hsu Yung-Jung 
Published: February 2024

With the inherently high degree of complexity, heterostructures composed of two or more materials joined in unique architectures may exhibit superior synergetic properties that are difficult or impossible to acquire from their individual constituents.[1-3] For semiconductor heterostructures, the relative band alignment of the constituents promotes effective charge separation to bring them desirable properties for photocatalysis applications. Among the different types of heterostructures, core-shell and yolk-shell nanocrystals have received particular interest due to their fascinating properties. Several representative works from our lab will be introduced to demonstrate the promising potentials of core-shell and yolk-shell nanocrystals for hydrogen production applications.

References

[1] Chun-Wen Tsao, Mei-Jing Fang, Yung-Jung Hsu*, “Modulation of interfacial charge dynamics of semiconductor heterostructures for advanced photocatalytic applications”, Coordination Chemistry Reviews
2021, 438, 213876 (Invited Review).
[2] Mei-Jing Fang, Chun-Wen Tsao, Yung-Jung Hsu*, "Semiconductor Nanoheterostructures for Photoconversion Applications", Journal of Physics D: Applied Physics
2020, 53, 143001 (Invited Review).
[3] Yi-An Chen, Yu-Ting Wang, Hyun Sik Moon, Kijung Yong, Yung-Jung Hsu*, "Yolk-shell nanostructures: synthesis, photocatalysis and interfacial charge dynamics", RSC Advances
2021, 11, 12288-12305 (Invited Review; selected as themed collections of Photocatalysis).
(Invited) Acid Stable Water Oxidation Catalysts for PEM Water Electrolysis
Authors: Nakamura Ryuhei 
Published: February 2024

Water electrolysis is a promising method to produce hydrogen from renewable electricity. However, the development of 3d metal catalysts for the oxygen evolution reaction (OER) is a critical challenge, especially in the case of polymer electrolyte membrane (PEM) electrolyzers, which are considered to be one of the most efficient electrolysis systems. The scarcity of iridium required for these systems prevents their widespread deployment at the global terawatt scale, and therefore the development of alternative catalysts has been highlighted as a real bottleneck for water electrolysis.
In this talk, I will report on how the incorporation of Mn into the Co3O4 spinel lattice can result in a two order of magnitude increase in stability without compromising activity (1, 2). I will also report on how the lifetime of Mn-based catalysts in acid can be extended by modulating the lattice oxygen structure (3). Finally, I will discuss the performance of Mn-based OER catalysis under the actual conditions of PEM water electrolysis (3).
(1) A. Li, S. Kong, C. Guo, H. Ooka, K. Adachi, D. Hashizume, Q. Jiang, H. Han, J. Xiao, R. Nakamura, Enhancing the stability of cobalt spinel oxide towards sustainable oxygen evolution in acid, Nat. Catal., 2022, 5, 109-118, DOI: 10.1038/s41929-021-00732-9
(2) A. Li, H. Ooka, N. Bonnet, T. Hayashi, Y. Sun, Q. Jiang, C. Li, H. Han, R. Nakamura, Stable potential windows for long-term electrocatalysis by manganese oxides under acidic conditions, Angew. Chem., Int. Ed., 2019, 58, 5054-5058. DOI: 10.1002/anie.201813361
(3) S. Kong, et al (under review)
Photocatalytic TiO2 Nanotube Layers on 3D Substrates Using Bipolar Electrochemistry
Authors: Sopha Hanna , Sepúlveda Sepúlveda Lina Marcela , Macak Jan M. 
Published: February 2024

Self-organized TiO2 nanotube (TNT) layers have attracted considerable scientific and technological interest over the past almost 20 years, due to their wide range of applications, including (photo-) catalysis, hydrogen generation and biomedical uses [1,2]. The synthesis of these TNT layers is usually carried out by electrochemical anodization of valve Ti metal substrates in various F--containing electrolytes using a conventional 2-electrode set-up with the Ti substrate as anode and a Pt-foil as cathode.
By now, the TiO2 nanotube layer modification of Ti substrates is mainly focused on planar substrates, such as Ti foils and 2D Ti meshes, as these substrates can easily be connected to the potentiostat during anodization. However, for the real application in photocatalytic cleaners, 3D Ti substrates, such as 3D meshes or Ti spheres, are of high interest due to their significantly increased surface area compressed in a small volume.
To anodize such 3D Ti substrates towards TiO2 nanotube layers, bipolar electrochemistry can be employed instead of using a conventional set-up [3-5]. In such a bipolar set-up, the Ti substrate is not directly connected to the potentiostat but placed in an electrolyte between two so-called feeder electrodes. Due to the electric field between the feeder electrodes, the Ti substrate is polarized and can be anodized if the applied potential between the feeder electrodes is high enough. This method opens the door for the preparation of TNT layers with gradients in dimensions (i.e. diameter and length of the nanotubes) [3-5] as well as for the preparation of TNT layers on Ti substrates, which cannot be directly connected to the potentiostat, e.g. small Ti spheres [6] and complicated 3D printed structures [7].
In this presentation, the preparation of TNT layers on small Ti spheres [6] as well as on 3D printed Ti substrates [7] using bipolar electrochemistry will be shown. Their application in liquid and gas phase photocatalysis will be discussed. Furthermore, we will also show the possibility of using closed bipolar electrochemical cells, consisting of two closed half-cells with the Ti substrate as obstacle between the cells for the preparation of TiO2 nanotube layers with different dimensions on the two sides of a classical Ti foil [8].
References:
[1] J.M. Macak et al., Curr. Opin. Solid State Mater.
2007, 11, 3.
[2] Lee, K. et al., Chem. Rev.
2014, 114, 9385.
[3] G. Loget et al, J. Mater. Chem A
2014, 2, 17740.
[4] G. Loget et al., Langmuir
2014, 30, 15356.
[5] W. Wei et al., Electrochim. Acta
2015, 176, 1393.
[6] H. Sopha et al., Electrochem. Commun.
2020, 111, 106669.
[7] H. Sopha et al., Nano Lett.
2021, 21, 8701.
[8] H. Sopha et al., ChemElectroChem
2021, 8, 3827.
Catalytic Activity of Au-Cu Alloy on TiO2 Nanotubes for Alcohol Oxidation
Authors: Lipinska Wiktoria , Grochowska Katarzyna , Karczewski Jakub , Coy Emerson , Siuzdak Katarzyna 
Published: February 2024

First fuel cell was discovered 180 years ago and still the ideal, namely cheap and effective catalytic materials are highly required. Such device allows to convert chemical energy into electrical one without pollutant gasses emission. In the case of alcohol fuel cells, methanol, ethanol, ethylene glycol and glycerine are considered as a power source. Platinum is commonly used for alcohol electrocatalyst, because of its high activity and stability. However, due to the high cost and limited supply platinum should be replaced by material that small amount is enough to reach satisfactory catalytic effect. In our work, we present the activity of gold-copper modified titania nanotubes toward electrocatalytic alcohol oxidation [1].
The material is fabricated using three steps such as: 1) anodization of Ti plate, 2) thin 10 nm AuCu alloy layer magnetron sputtering, and 3) rapid thermal annealing in an argon atmosphere [2]. Scanning electron microscopy confirmed the presence of well-ordered TiO2 nanotubes (TiNT) with diameter of 101 ± 13 nm and length of 709± 53 nm. After AuCu alloy magnetron sputtering and thermal treatment spherical nanoparticles were formed on NT surface. Based on top view SEM images the diameter of gold copper nanoparticles is equal to 38 ± 5 nm. However, the TEM images showed that diameter of nanoparticles changes from 5 nm to 60 nm (Figure 1a-d) where the bigger particles are on the top of the nanotubes. Applied fabrication procedure allowed us to obtain electrode material that can be used in methanol, ethylene glycol or glycerine oxidation. The highest catalytic activity of AuCu alloy was obtained for glycerine oxidation. Prepared material exhibited 90 times higher current density after glycerine addition to the alkaline solution than pure TiNT (Figure 1e). Furthermore, higher current density towards alcohol oxidation was registered for thermally annealed sample (an-AuCu/TiNT) than for non-annealed one (n-AuCu/TiNT).
Cyclic voltammetry measurements for the an-AuCu/TiNT in glycerine solution at different scan rates confirmed diffusion controlled process. The oxidation peak current density located at +0.3 V and +1 V grows up to 120 mV/s with slope of 51 and 81 µA/cm2 respectively, which confirmed more privilege process at +1 V vs. Ag/AgCl/0.1M KCl. We believe that the information reported in our work provide wider knowledge about new and more efficient electrodes for alcohol oxidation.
Research is financed by National Science Centre (Poland): Grant No. 2019/35/N/ST5/02604
[1] W. Lipińska et al. Journal of Materials Science, 57 (2022) 13345, DOI:10.1007/s10853-022-07471-7
[2] W. Lipińska et al. ACS Applied Materials & Interfaces, 13 (2021) 52967, DOI:10.1021/acsami.1c16271

Figure 1