Inorganics

14 pages, 12579 KiB

Open AccessArticle

Luminescence Efficiency and Spectral Compatibility of Cerium Fluoride (CeF₃) Inorganic Scintillator with Various Optical Sensors in the Diagnostic Radiology X-ray Energy Range

by Vasileios Ntoupis, Christos Michail, Nektarios Kalyvas, Athanasios Bakas, Ioannis Kandarakis, George Fountos and Ioannis Valais

Inorganics 2024, 12(8), 230; https://doi.org/10.3390/inorganics12080230 - 22 Aug 2024

Viewed by 717

Abstract

The aim of this study was to experimentally assess the luminescence efficiency of a cerium fluoride (CeF₃) inorganic scintillator in crystal form as a possible alternative to high-luminescence but hygroscopic cerium bromide (CeBr₃). The experiments were performed under typical [...] Read more.

The aim of this study was to experimentally assess the luminescence efficiency of a cerium fluoride (CeF₃) inorganic scintillator in crystal form as a possible alternative to high-luminescence but hygroscopic cerium bromide (CeBr₃). The experiments were performed under typical diagnostic radiology X-rays (50–140 kVp). Parameters such as the crystal’s absolute luminescence efficiency (AE) and the spectral matching with a series of optical detectors were examined. The replacement of bromine with fluorine appeared to drastically reduce the AE of CeF₃ compared to CeBr₃ and other commercially available inorganic scintillators such as bismuth germanate (Bi₄Ge₃O₁₂-BGO). CeF₃ reaches a maximum luminescence efficiency value of only 0.8334 efficiency units (EUs) at 140 kVp, whereas the corresponding values for CeBr₃ and BGO were 29.49 and 3.41, respectively. Furthermore, the emission maximum (at around 313 nm) moved towards the lower part of the visible spectrum, making CeF₃ suitable for spectral coupling with various photocathodes and photomultipliers applied in nuclear medicine detectors, but completely unsuitable for spectral matching with CCDs and CMOS. The obtained luminescence efficiency results denote that CeF₃ cannot be applied in medical imaging applications covering the range 50–140 kVp; however, examination of its luminescence output in the nuclear medicine energy range (~70 to 511 keV) could reveal possible applicability in these modalities. Full article

(This article belongs to the Special Issue Functional Inorganic Biomaterials for Molecular Sensing and Biomedical Applications)

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18 pages, 8274 KiB

Open AccessArticle

Preparation of Non-Noble Metal Catalyst FeCo₂O₄/MoS₂ for Production of Hydrogen and Oxygen by Electrochemical Decomposition of Water

by Zhouqian Chen, Zongmei Li, Manyi Zhang, Yujia Wang, Siang Zhang and Yuanyuan Cheng

Inorganics 2024, 12(8), 229; https://doi.org/10.3390/inorganics12080229 - 22 Aug 2024

Viewed by 898

Abstract

FeCo₂O₄/MoS₂ binary composite catalysts were prepared by the hydrothermal method and calcination method. In this paper, the morphology and structure of the materials were characterized by means of SEM, EDS, XRD, and XPS. It was found that MoS [...] Read more.

FeCo₂O₄/MoS₂ binary composite catalysts were prepared by the hydrothermal method and calcination method. In this paper, the morphology and structure of the materials were characterized by means of SEM, EDS, XRD, and XPS. It was found that MoS₂ has high activity and good stability in HER, and and it has more prospect than noble metal catalysts. In oxygen evolution chemical kinetics, its rich redox potential allowed it to adsorb OH⁻ on (Co²⁺/Co³⁺, Fe²⁺/Fe³⁺) and enhanced the activity of OER. The cross-nanosheet structure of the FeCo₂O₄/MoS₂ composite catalyst exposed more catalytic sites and accelerated charge transfer to achieve more efficient mass transfer. FeCo₂O₄/MoS₂ as an anode and cathode was assembled into a two-electrode system in overall water splitting, which showed good catalytic activity. When the composite ratio of FeCo₂O₄ to MoS₂ was 1:0.3, the composite catalyst had the best catalytic activity. The results show that when FeCo₂O₄/MoS₂ is used as a cathode and anode to assemble an alkaline cell, respectively, the voltage for total water electrolysis is 1.59 V at a current density of 10 mA cm⁻² in a 1 M KOH electrolyte, it can keep good stability in a 10 h test with electrolyzed water, and its current retention rate is 98.5%. Full article

(This article belongs to the Section Inorganic Materials)

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16 pages, 5968 KiB

Open AccessArticle

Infrared Light Annealing Effect on Pressure Sensor Fabrication Using Graphene/Polyvinylidene Fluoride Nanocomposite

by Victor K. Samoei, Katsuhiko Takeda, Keiichiro Sano, Angshuman Bharadwaz, Ambalangodage C. Jayasuriya and Ahalapitiya H. Jayatissa

Inorganics 2024, 12(8), 228; https://doi.org/10.3390/inorganics12080228 - 21 Aug 2024

Viewed by 861

Abstract

This paper reports the designing and testing, as well as the processing and testing, of a flexible piezoresistive sensor for pressure-sensing applications, utilizing a composite film of graphene/polyvinylidene fluoride (Gr/PVDF). Graphene serves as the conductive matrix, while PVDF acts as both the binder [...] Read more.

This paper reports the designing and testing, as well as the processing and testing, of a flexible piezoresistive sensor for pressure-sensing applications, utilizing a composite film of graphene/polyvinylidene fluoride (Gr/PVDF). Graphene serves as the conductive matrix, while PVDF acts as both the binder and a flexible polymer matrix. The composite film was fabricated using the solution casting technique on a flexible polyethylene substrate. We investigated the impact of post-infrared annealing on the pressure response of the Gr/PVDF films. The experimental results indicated that the films IR-annealed for 2 min exhibited improved pressure sensitivity compared with the as-deposited films. The stability and durability of the sensors were assessed through the application of pressure over more than 1000 cycles. The mechanical properties of the films were examined using a universal tensile testing machine (UTM) for scenarios both with and without infrared light annealing. Raman spectroscopy was employed to analyze the quality and characteristics of the prepared nanocomposites. This study enhances our understanding of the interplay between the Gr/PVDF composite, the IR annealing effect, and the hysteresis effect in the pressure-sensing mechanism, thereby improving the piezoresistance of the Gr/PVDF nanocomposite through the infrared annealing process. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Advanced Technology)

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15 pages, 13117 KiB

Open AccessArticle

Raman Spectroscopy and Microstructural Characterization of Hot-Rolled Copper/Graphene Composite Materials

by Antoine Bident, Jean-Luc Grosseau-Poussard, Florence Delange, Ahmed Addad, Gang Ji, Yongfeng Lu, Jean-Louis Bobet, Amélie Veillere and Jean-François Silvain

Inorganics 2024, 12(8), 227; https://doi.org/10.3390/inorganics12080227 - 20 Aug 2024

Viewed by 684

Abstract

Given the increase in current density in the constituent materials of electrical systems, improving the electrical conductivity of these materials, particularly copper (Cu), is crucial. This would also help to mitigate the heat generated by Joule heating. The incorporation of graphene (Gr) into [...] Read more.

Given the increase in current density in the constituent materials of electrical systems, improving the electrical conductivity of these materials, particularly copper (Cu), is crucial. This would also help to mitigate the heat generated by Joule heating. The incorporation of graphene (Gr) into a composite material (Cu/Gr) is a viable solution. However, to ensure the proper transfer of properties between the reinforcement and the matrix, several elements must be considered, including the orientation of the reinforcement. As a 2D material, controlling graphene’s orientation within the structure is essential but often overlooked. To address this issue, hot rolling was implemented to improve the alignment of the reinforcement. The inclusion of graphene led to a 12 HV increase in the material’s hardness, demonstrating a positive composite effect. Simultaneously, rolling increased the material’s hardness from 67.6 to 75.1 HV by introducing more dislocations into the material. To characterize the graphene’s alignment, polarized Raman spectroscopy was used. This technique highlighted the improved alignment of the reinforcement in the rolling direction, a change that was visible and confirmed by scanning electron microscopy micrographs. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Advanced Technology)

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13 pages, 3260 KiB

Open AccessArticle

Two Perovskite Modifications of BiFe_0.6Mn_0.4O₃ Prepared by High-Pressure and Post-Synthesis Annealing at Ambient Pressure

by Alexei A. Belik

Inorganics 2024, 12(8), 226; https://doi.org/10.3390/inorganics12080226 - 19 Aug 2024

Cited by 1 | Viewed by 577

Abstract

BiFeO₃-related perovskite-type materials attract a lot of attention from the viewpoint of applications and fundamental science. In this work, we prepared two modifications of heavily Mn-doped BiFeO₃ with the composition of BiFe_0.6Mn_0.4O₃. A high-pressure [...] Read more.

BiFeO₃-related perovskite-type materials attract a lot of attention from the viewpoint of applications and fundamental science. In this work, we prepared two modifications of heavily Mn-doped BiFeO₃ with the composition of BiFe_0.6Mn_0.4O₃. A high-pressure (HP) modification was prepared at about 6 GPa and 1400 K. An ambient pressure (AP) modification was prepared by heating the HP modification at 780 K in the air at AP (post-synthesis annealing). Crystal structures of both modifications and in situ transformation were investigated with synchrotron powder X-ray diffraction. The transformation started at about 700 K and finished at about 780 K. The HP modification crystallized in space group Pnma with a = 5.57956 Å, b = 15.70576 Å, and c = 11.22557 Å, and the AP modification crystallized in space group Pbam with a = 5.63839 Å, b = 11.2710 Å, and c = 7.75923 Å (all parameters were at room temperature). Post-synthesis annealing of the HP modification (conversion polymorphism) is the only way to prepare the Pbam modification of oxygen stoichiometric BiFe_0.6Mn_0.4O₃. Magnetic properties of both modifications have been reported. The Néel temperatures are T_N = 350 K (HP) and T_N = 335 K (AP). HP modification shows larger spin canting. Both modifications show negative magnetization phenomena at low temperatures in low magnetic fields. Full article

(This article belongs to the Special Issue The State of the Art of Research on Perovskites Materials)

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18 pages, 10803 KiB

Open AccessArticle

Novel NH₄V₄O₁₀-Reduced Graphene Oxide Cathodes for Zinc-Ion Batteries: Theoretical Predictions and Experimental Validation

by He Lin, Chenfan Liu and Yu Zhang

Inorganics 2024, 12(8), 225; https://doi.org/10.3390/inorganics12080225 - 17 Aug 2024

Viewed by 1324

Abstract

This investigation explores the potential of enhancing aqueous zinc-ion batteries (AZIBs) through the introduction of a novel cathode material, NH₄V₄O₁₀ (NVO), combined with reduced graphene oxide (rGO). Utilizing Density Functional Theory (DFT), it was hypothesized that the incorporation [...] Read more.

This investigation explores the potential of enhancing aqueous zinc-ion batteries (AZIBs) through the introduction of a novel cathode material, NH₄V₄O₁₀ (NVO), combined with reduced graphene oxide (rGO). Utilizing Density Functional Theory (DFT), it was hypothesized that the incorporation of rGO would increase the interlayer spacing of NVO and diminish the charge transfer interactions, thus promoting enhanced diffusion of Zn²⁺ ions. These theoretical predictions were substantiated by experimental data acquired from hydrothermal synthesis, which indicated a marked increase in interlayer spacing. Significantly, the NVO–rGO composite exhibits remarkable cyclic durability, maintaining 95% of its initial specific capacity of 507 mAh g⁻¹ after 600 cycles at a current density of 5 A g⁻¹. The electrochemical performance of NVO–rGO not only surpasses that of pristine NVO but also outperforms the majority of existing vanadium oxide cathode materials reported in the literature. This study underscores the effective integration of theoretical insights and experimental validation, contributing to the advancement of high-performance energy storage technologies. Full article

(This article belongs to the Special Issue Advances in Electrodes and Electrolyte Engineering for High-Performance Zn Batteries and Supercapacitors)

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19 pages, 6237 KiB

Open AccessReview

The Story, Properties and Applications of Bioactive Glass “1d”: From Concept to Early Clinical Trials

by Dilshat U. Tulyaganov, Simeon Agathopoulos, Konstantinos Dimitriadis, Hugo R. Fernandes, Roberta Gabrieli and Francesco Baino

Inorganics 2024, 12(8), 224; https://doi.org/10.3390/inorganics12080224 - 17 Aug 2024

Viewed by 945

Abstract

Bioactive glasses in the CaO–MgO–Na₂O–P₂O₅–SiO₂–CaF₂ system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside–fluorapatite–wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of [...] Read more.

Bioactive glasses in the CaO–MgO–Na₂O–P₂O₅–SiO₂–CaF₂ system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside–fluorapatite–wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of mechanical behaviour and overall bone-regenerative potential. In this review, we describe and critically discuss the genesis, development, properties and applications of bioactive glass “1d” and its relevant GC derivative products, which can be considered a good example of success cases in this class of SiO₂/CaO-based biocompatible materials. Bioactive glass 1d can be produced by melt-quenching in the form of powder or monolithic pieces, and was also used to prepare injectable pastes and three-dimensional porous scaffolds. Over the past 15 years, it was investigated by the authors of this article in a number of in vitro, in vivo (with animals) and clinical studies, proving to be a great option for hard tissue engineering applications. Full article

(This article belongs to the Special Issue New Advances into Nanostructured Oxides, 2nd Edition)

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24 pages, 37699 KiB

Open AccessArticle

Synthesis and Redox Properties of Iron and Iron Oxide Nanoparticles Obtained by Exsolution from Perovskite Ferrites Promoted by Auxiliary Reactions

by Dmitrii Filimonov, Marina Rozova, Sergey Maksimov and Denis Pankratov

Inorganics 2024, 12(8), 223; https://doi.org/10.3390/inorganics12080223 - 16 Aug 2024

Viewed by 1012

Abstract

Nanoparticles of iron and iron oxides, as well as their composites, are of great scientific and technological interest. However, their properties and sustainability strongly depend on the preparation methods. Here, we present an original approach to synthesizing Fe and FeNi_x metal nanoparticles [...] Read more.

Nanoparticles of iron and iron oxides, as well as their composites, are of great scientific and technological interest. However, their properties and sustainability strongly depend on the preparation methods. Here, we present an original approach to synthesizing Fe and FeNi_x metal nanoparticles by exsolution, in a reducing environment at elevated temperatures from perovskite ferrites (La_1−xCa_xFeO_3−γ, CaFeO_2.5, etc.). This approach is made possible by the auxiliary reactions of non-reducible A-site cations (in ABO₃ notation) with the constituents of reducing compounds (h-BN etc.). The nanoparticles exsolved by our process are embedded in oxide matrices in individual voids formed in situ. They readily undergo redox cycling at moderate temperatures, while maintaining their localization. Fe nanoparticles can be obtained initially and after redox cycling in the high-temperature γ-form at temperatures below equilibrium. Using their redox properties, a new route to producing hollow and layered oxide magnetic nanoparticles (Fe₃O₄, Fe₃O₄/La_1−xCa_xFeO_3−γ), by separating the oxidized exsolved particles, was developed. Our approach provides greater flexibility in controlling exsolution reactions and matrix compositions, with a variety of possible starting compounds and exsolution degrees, from minimal up to ~100% (in some cases). The described strategy is highly important for the development of a wide range of new functional materials. Full article

(This article belongs to the Special Issue New Advances into Nanostructured Oxides, 2nd Edition)

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19 pages, 6823 KiB

Open AccessReview

Exploring the Frontiers of Cathode Catalysts in Lithium–Carbon Dioxide Batteries: A Mini Review

by Jing Guo, Xin Yan, Xue Meng, Pengwei Li, Qin Wang, Yahui Zhang, Shenxue Yan and Shaohua Luo

Inorganics 2024, 12(8), 222; https://doi.org/10.3390/inorganics12080222 - 16 Aug 2024

Viewed by 858

Abstract

To mitigate the greenhouse effect and environmental pollution caused by the consumption of fossil fuels, recent research has focused on developing renewable energy sources and new high-efficiency, environmentally friendly energy storage technologies. Among these, Li–CO₂ batteries have shown great potential due to [...] Read more.

To mitigate the greenhouse effect and environmental pollution caused by the consumption of fossil fuels, recent research has focused on developing renewable energy sources and new high-efficiency, environmentally friendly energy storage technologies. Among these, Li–CO₂ batteries have shown great potential due to their high energy density, long discharge plateau, and environmental friendliness, offering a promising solution for achieving carbon neutrality while advancing energy storage devices. However, the slow kinetics of the CO₂ reduction reaction and the accumulation of Li₂CO₃ discharge on the cathode surface lead to a significant reduction in space and active sites. This in turn results in high discharge overpotential, low energy efficiency, and low power density. This study elucidates the charge–discharge reaction mechanisms of lithium–carbon dioxide batteries and systematically analyzes their reaction products. It also summarizes the latest research advancements in cathode materials for these batteries. Furthermore, it proposes future directions and efforts for the development of Li–CO₂ batteries. Full article

(This article belongs to the Special Issue Novel Materials in Li–Ion Batteries)

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33 pages, 7728 KiB

Open AccessReview

C–H Activation via Group 8–10 Pincer Complexes: A Mechanistic Approach

by Juan S. Serrano-García, Andrés Amaya-Flórez, Jordi R.-Galindo, Lucero González-Sebastián, Luis Humberto Delgado-Rangel and David Morales-Morales

Inorganics 2024, 12(8), 221; https://doi.org/10.3390/inorganics12080221 - 15 Aug 2024

Viewed by 1268

Abstract

C–H bond activation is a crucial synthetic strategy widely utilized in both academic and industrial settings. Due to the strong and kinetically inert nature of the C–H bond, its functionalization typically requires metal-based catalysts. This review highlights the most significant advancements in homogeneously [...] Read more.

C–H bond activation is a crucial synthetic strategy widely utilized in both academic and industrial settings. Due to the strong and kinetically inert nature of the C–H bond, its functionalization typically requires metal-based catalysts. This review highlights the most significant advancements in homogeneously catalyzed reactions using pincer complexes with metals from groups 8–10, capable of promoting challenging C–H activation, published since 2010. In particular, it focuses on C–H bond activation for borylation, isomerization, and dehydrogenation, among other processes, discussing their scope and mechanistic insights. Full article

(This article belongs to the Special Issue C–H Bond Activation by Transition Metal Complexes)

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16 pages, 6371 KiB

Open AccessArticle

Tetrahydroxidohexaoxidopentaborate(1-) Salts of C₆-Linked Substituted Diimidazolium and Dipyrrolidinium Cations: Synthesis, Characterization and XRD Studies

by Ahmad R. Al-Dulayymi, Michael A. Beckett, Radek Braganca, Simon J. Coles, Peter N. Horton and Thomas A. Rixon

Inorganics 2024, 12(8), 220; https://doi.org/10.3390/inorganics12080220 - 15 Aug 2024

Viewed by 710

Abstract

Several tetrahydroxidohexaoxidopentaborate(1-) salts of N-substituted diimidazolium cations or N-substituted dipyrrolidinium cations linked through N-C₆-N chains have been synthesized and characterized spectroscopically (NMR, IR) and by single-crystal XRD studies: [R(NC₃H₃N)(CH₂)₆(NC [...] Read more.

Several tetrahydroxidohexaoxidopentaborate(1-) salts of N-substituted diimidazolium cations or N-substituted dipyrrolidinium cations linked through N-C₆-N chains have been synthesized and characterized spectroscopically (NMR, IR) and by single-crystal XRD studies: [R(NC₃H₃N)(CH₂)₆(NC₃H₃N)R][B₅O₆(OH)₄]₂·xH₂O (R = Me, x = 0 (1); R = Et, x = 3 (2); [Me(NC₃H₃N)(CH₂(C₆H₄)CH₂)(NC₃H₃N)Me][B₅O₆(OH)₄]₂ (3), [(C₄H₈N)(R)(CH₂)₆(R)(NC₄H₈)][B₅O₆(OH)₄]₂·xB(OH)₃ (R = Me, x = 0 (4, two polymorphs); R = Et, x = 0 (5); R = Bu, x = 4 (6); R = allyl, x = 0 (7)). Representative samples (1 and 7) were also characterized by thermal (TGA/DSC) studies; compounds are thermally decomposed to B₂O₃ in air. Numerous anion-anion H-bonding interactions are present in the solid-state structures of 1–5 and 7 as giant anionic networks. Unusually, in 6 there are no R₂²(8) anion-anion interactions as the co-crystallized B(OH)₃ bridges between all pentaborate anions. H-bonding interactions in 1–7 have been examined using Etter graph set analysis; C(8), C₃³(18), R₂²(8), R₂²(12) and R₄⁴(12) motifs have been identified. Full article

(This article belongs to the Section Inorganic Solid-State Chemistry)

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13 pages, 5777 KiB

Open AccessArticle

Characterization and Degradation of Perovskite Mini-Modules

by R. Ebner, A. Mittal, G. Ujvari, M. Hadjipanayi, V. Paraskeva, G. E. Georghiou, A. Hadipour, A. Aguirre and T. Aernouts

Inorganics 2024, 12(8), 219; https://doi.org/10.3390/inorganics12080219 - 15 Aug 2024

Viewed by 915

Abstract

Organic–inorganic hybrid metal halide perovskites are poised to revolutionize the next generation of photovoltaics with their exceptional optoelectronic properties and compatibility with low-cost and large-scale fabrication methods. Since perovskite tends to degrade over short time intervals due to various parameters (oxygen, humidity, light, [...] Read more.

Organic–inorganic hybrid metal halide perovskites are poised to revolutionize the next generation of photovoltaics with their exceptional optoelectronic properties and compatibility with low-cost and large-scale fabrication methods. Since perovskite tends to degrade over short time intervals due to various parameters (oxygen, humidity, light, and temperature), advanced characterization methods are needed to understand their degradation mechanisms. In this context, investigation of the electrical and optoelectronic properties of several perovskite mini-modules was performed by means of photo- and electroluminescence imaging as well as Dark Lock-In Thermography methods. Current–voltage curves at periodic time intervals and External Quantum Efficiency measurements were implemented alongside other measurements to reveal correlations between the electrical and radiative properties of the solar cells. The different imaging techniques used in this study reveal the changes in radiative emission processes and how those are correlated with performance. Alongside the indoor optoelectronic characterization of perovskite reference samples, the outdoor monitoring of two perovskite modules of the same structure for 23 weeks is reported. Significant performance degradation is presented outdoors from the first week of testing for both samples under test. The evolution of the major electrical characteristics of the mini-modules and the diurnal changes were studied in detail. Finally, dark storage recovery studies after outdoor exposure were implemented to investigate changes in the major electrical parameters. Full article

(This article belongs to the Special Issue The State of the Art of Research on Perovskites Materials)

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13 pages, 3050 KiB

Open AccessArticle

Boosting the Performance of Lithium-Sulfur Batteries with PY−DHBD−COF-Enhanced Separators

by Hong He, Wei Wang and Xiaobei Guo

Inorganics 2024, 12(8), 218; https://doi.org/10.3390/inorganics12080218 - 14 Aug 2024

Viewed by 835

Abstract

Lithium–sulfur batteries (LSBs) hold promise for use in next-generation high-energy-density energy storage systems. However, the commercial application of LSBs is hindered by the shuttle effect of polysulfides. In this study, we synthesized a covalent organic framework material (PY−DHBD−COF) and employed it to modify [...] Read more.

Lithium–sulfur batteries (LSBs) hold promise for use in next-generation high-energy-density energy storage systems. However, the commercial application of LSBs is hindered by the shuttle effect of polysulfides. In this study, we synthesized a covalent organic framework material (PY−DHBD−COF) and employed it to modify the separators of LSBs in order to buffer the shuttle effect of polysulfides. A modified separator, involving PY−DHBD−COF coating of the commercial Celgard 2500 PP separator, is prepared via a vacuum-assisted self-assembly method. The PY−DHBD−COF features hydroxyl and imine bonds, which can adsorb lithium polysulfides (LiPSs) and buffer the shuttle effect. The PY−DHBD−COF coating exhibits a thin thickness and oriented nanochannels, facilitating electrolyte wetting and Li⁺ transport. As a result, the LSBs with PY−DHBD−COF-modified separators exhibit a high specific capacity of 373 mAh g⁻¹ at 4 C with only 0.005% capacity decay per cycle after 450 cycles at 2 C, demonstrating an excellent cycling performance. Full article

(This article belongs to the Section Inorganic Materials)

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17 pages, 3113 KiB

Open AccessArticle

Compositional and Fabrication Cycle Optimization of Ceria-Zirconia-Supported Mo-Based Catalysts for NH₃-SCR NO_x Reduction

by Luca Spiridigliozzi, Viviana Monfreda, Serena Esposito, Olimpia Tammaro, Nicola Blangetti, Fabio Alessandro Deorsola and Gianfranco Dell’Agli

Inorganics 2024, 12(8), 217; https://doi.org/10.3390/inorganics12080217 - 10 Aug 2024

Viewed by 625

Abstract

The reduction of nitrogen oxides (NO_x), critical pollutants from stationary to mobile sources, mainly relies on the selective catalytic reduction (NH₃-SCR) method, employing ammonia to reduce NO_x into nitrogen and water. However, conventional catalysts, while effective, pose both [...] Read more.

The reduction of nitrogen oxides (NO_x), critical pollutants from stationary to mobile sources, mainly relies on the selective catalytic reduction (NH₃-SCR) method, employing ammonia to reduce NO_x into nitrogen and water. However, conventional catalysts, while effective, pose both environmental and operational challenges. This study investigates ceria-zirconia-supported molybdenum-based catalysts, exploring the effects of zirconium doping and different catalyst synthesis techniques, i.e., co-precipitation and impregnation. The catalytic performance of the differently prepared samples was significantly influenced by the molybdenum incorporation method and the zirconium content within the ceria-zirconia support. Co-precipitation at higher temperatures resulted in catalysts with better structural attributes but slightly lower catalytic activity compared to those prepared via impregnation. Optimal NO_x reduction (close to 100%) was observed at a 15 mol% zirconium doping level when using the impregnation method. Full article

(This article belongs to the Special Issue Metal Catalyst Discovery, Design and Synthesis)

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5 pages, 191 KiB

Open AccessEditorial

Iron–Sulfur Clusters: Assembly and Biological Roles

by Nunziata Maio

Inorganics 2024, 12(8), 216; https://doi.org/10.3390/inorganics12080216 - 9 Aug 2024

Viewed by 1183

Abstract

Iron–sulfur (Fe-S) clusters are critical to a wide range of biological processes, from DNA repair and transcriptional regulation to mitochondrial respiration and enzymatic catalysis [...] Full article

(This article belongs to the Special Issue Iron-Sulfur Clusters: Assembly and Biological Roles)

16 pages, 1934 KiB

Open AccessArticle

Nickel Ions Activated PbO–GeO₂ Glasses for the Application of Electrolytes and Photonic Devices

by L. Vijayalakshmi, Shaik Meera Saheb, R. Vijay, Kishor Palle, P. Ramesh Babu, Seong-Jin Kwon and G. Naga Raju

Inorganics 2024, 12(8), 215; https://doi.org/10.3390/inorganics12080215 - 8 Aug 2024

Viewed by 795

Abstract

In this study, PbO–GeO₂ glasses were melt-quenched at different nickel oxide concentrations. XRD and DSC techniques were characterized whether the samples are glass or crystalline materials. IR, Raman, and optical absorption techniques are used to obtain structural details. The IR spectra have [...] Read more.

In this study, PbO–GeO₂ glasses were melt-quenched at different nickel oxide concentrations. XRD and DSC techniques were characterized whether the samples are glass or crystalline materials. IR, Raman, and optical absorption techniques are used to obtain structural details. The IR spectra have revealed that the glass network contained conventional structural units GeO₄ and GeO₆. The Ni²⁺ ion octahedral transition exhibited luminescence spectra in the region of 1200–1500 nm; it is due to ³T₂ (3F) → ³A₂(3F) transition. The glasses containing the highest concentration of NiO have been found to have high values of luminescence efficiency and the cross-section. The dielectric characteristics, such as the dielectric constant, loss, and a.c. conductivity (σ_ac), were analyzed across extensive frequency and temperature ranges, with a specific emphasis on the nickel oxide concentration. Analyzing optical absorption and dielectric properties of the samples, it has been found that nickel ions’ majority occur in tetrahedral sites. It is proved that the dielectric constant and loss values are highest for the sample N₁₀ and ac conductivity due to dipoles being lowest for the sample N₁₀. It is revealed that the glasses are highly conducting due to the modifying action of Ni²⁺ ions so these glasses are suitable for solid electrolyte uses besides their optical applications in NLO devices. Full article

(This article belongs to the Special Issue Recent Research and Application of Amorphous Materials)

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12 pages, 3705 KiB

Open AccessArticle

Improving Charge Transport in Perovskite Solar Cells Using Solvent Additive Technique

by Ahmed Hayali and Maan M. Alkaisi

Inorganics 2024, 12(8), 214; https://doi.org/10.3390/inorganics12080214 - 8 Aug 2024

Viewed by 811

Abstract

Perovskite solar cells (PSCs) have demonstrated remarkable progress in performance in recent years, which has placed perovskite materials as the leading promising materials for future renewable energy applications. The solvent additive technique in perovskite composition is a simple but effective process used to [...] Read more.

Perovskite solar cells (PSCs) have demonstrated remarkable progress in performance in recent years, which has placed perovskite materials as the leading promising materials for future renewable energy applications. The solvent additive technique in perovskite composition is a simple but effective process used to improve the surface quality of the perovskite layers and to improve the performance and charge transport processes essential to the functions of PSCs. These additives can have a considerable effect on the topography, crystallinity, and surface properties of the perovskite active layer, ultimately influencing the stability of the PSCs. A “two-step spin coating” deposition method to make PSCs in ambient air laboratory conditions was employed. Acetonitrile (ACN) was conventionally utilized as a chemical additive to enhance the performance of PSCs. In this study, our film properties exhibited that the incorporation of ACN in the triple cation perovskite precursor led to the passivation of surface defects and a noticeable increase in the size of the crystal grains of the perovskite films, which led to enhanced stability of devices. The efficiency achieved for PSCs prepared with 10% ACN was 15.35%, which is 30% higher than devices prepared without ACN. In addition, devices prepared with ACN have shown a lower hysteresis index and more stable behavior compared to devices prepared without ACN. This work presents an easy, low-cost method for the fabrication of high performance PSCs prepared under ambient air laboratory conditions. Full article

(This article belongs to the Special Issue The State of the Art of Research on Perovskites Materials)

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10 pages, 3745 KiB

Open AccessArticle

Polysilane–Barium Titanate Polymeric Composite Obtained through Ultrasonication

by Răzvan Rotaru, Maria Emiliana Fortună, Elena Ungureanu and Liviu Sacarescu

Inorganics 2024, 12(8), 213; https://doi.org/10.3390/inorganics12080213 - 7 Aug 2024

Viewed by 864

Abstract

This work describes the synthesis of a polysilane (PSH)–barium titanate (BT) ferroelectric polymer composite that keeps stable in the presence of ultraviolet light (UV). To evaluate the stability in the presence of UV radiation and the mechanism of interaction between the PSH matrix [...] Read more.

This work describes the synthesis of a polysilane (PSH)–barium titanate (BT) ferroelectric polymer composite that keeps stable in the presence of ultraviolet light (UV). To evaluate the stability in the presence of UV radiation and the mechanism of interaction between the PSH matrix and BT, FTIR measurements were carried out. The UV/VIS absorption measurement reveals that PSH absorbs strongly in the ultraviolet range, while the composite behaves similarly to BT. Although PSH is a semiconductor, the dielectric spectrometry analysis determined that BT is a ferroelectric material due to its high dielectric constant and low dielectric losses. In contrast to the polymer matrix, the composite polymer has a greater dielectric constant and a lower loss permittivity. PSH is a semiconductor, as indicated by its electrical conductivity of 10⁻⁵ S/cm; nevertheless, the UV-irradiated polymer has antistatic properties (10⁻⁸ S/cm). Irradiated or not, the polymer composite is a semiconductor, with conductivity of 10⁻⁶ S/cm, significantly lower than that of PSH. The interaction with electromagnetic radiation indicates electromagnetic shielding behavior for both BT (highest absorption magnitude of −57 dB) and the polymer composite (maximum absorption magnitudes range from 8.4 to −15.2 dB). Based on these research results, the novel composite with specific characteristics may be used in electronic applications in UV-irradiated conditions. Full article

(This article belongs to the Special Issue Advanced Inorganic Semiconductor Materials, 2nd Edition)

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13 pages, 5577 KiB

Open AccessArticle

Effect of Salt Variability on the Low-Temperature Metal-Catalyzed Graphitization of PAN/DMSO Solutions for the Synthesis of Nanostructured Graphitic Carbon

by Taewoo Kim, Byoung-Suhk Kim, Tae Hoon Ko and Hak Yong Kim

Inorganics 2024, 12(8), 212; https://doi.org/10.3390/inorganics12080212 - 2 Aug 2024

Viewed by 938

Abstract

Graphitic carbon plays a pivotal role in numerous technological applications, including energy storage, energy conversion, and different fields of material science. The transformation of amorphous carbon into graphitic carbon, a process known as graphitization, is important for optimizing the properties of carbon materials. [...] Read more.

Graphitic carbon plays a pivotal role in numerous technological applications, including energy storage, energy conversion, and different fields of material science. The transformation of amorphous carbon into graphitic carbon, a process known as graphitization, is important for optimizing the properties of carbon materials. In this study, we explore the catalytic graphitization of polyacrylonitrile (PANs) using various metal salts (LiNO₃, Ca(NO₃)₂·4H₂O, and Ni(NO₃)₂·6H₂O). We prepared dimethyl sulfoxide (DMSO) solutions of PAN with different salt concentrations of 5, 10, and 15 wt.%. The different prepared metal salt-mixed PAN/DMSO solutions were dried at 45 °C and this was followed by carbonization processes at 950 °C, with a heating rate of 1 °C min⁻¹ for 1 h under an N₂ atmosphere. The resulting graphitic carbon was characterized to determine the influence of salt type and concentration on the degree of graphitization. Our findings provide valuable insights into PAN-derived graphitic carbon’s structural and compositional properties. This work underscores the influence of salt concentration in optimizing the graphitization process, offering a pathway to design facile and cost-effective graphitic carbon materials. Full article

(This article belongs to the Section Inorganic Solid-State Chemistry)

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11 pages, 941 KiB

Open AccessArticle

First-Principles Study of Strain Effects on the Perpendicular Magnetic Anisotropy of Fe/MgO Heterostructures

by Safdar Nazir, Sicong Jiang and Kesong Yang

Inorganics 2024, 12(8), 211; https://doi.org/10.3390/inorganics12080211 - 2 Aug 2024

Cited by 1 | Viewed by 895

Abstract

The interfacial perpendicular magnetic anisotropy (PMA) observed at ferromagnet/oxide interfaces presents great promise for energy-efficient spintronic technologies. The epitaxial strain induced by the lattice mismatch between films and substrates serves as an effective strategy for the tuning of the material properties. However, the [...] Read more.

The interfacial perpendicular magnetic anisotropy (PMA) observed at ferromagnet/oxide interfaces presents great promise for energy-efficient spintronic technologies. The epitaxial strain induced by the lattice mismatch between films and substrates serves as an effective strategy for the tuning of the material properties. However, the current understanding of the strain effects on interfacial PMA remains insufficient. Here, we present an extensive study of the biaxial strain effects on the interfacial magnetism and interfacial magnetic anisotropy constant (

K_{i}

) in a slab-based Fe/MgO heterostructure using first-principles density functional theory calculations. Our results reveal a strong correlation between the spin moment of interfacial Fe atoms and the Fe-O bond length in both unstrained and strained systems. The overall

K_{i}

, which includes contributions from both the Fe/MgO interface and the Fe surface, increases as the compressive strain increases. This is consistent with recent experimental findings that show that the PMA energy increases when the in-plane lattice constant of Fe decreases. In contrast, the overall

K_{i}

initially decreases with a small tensile strain of less than 0.4% and shows an increasing trend as the tensile strain increases from 0.4% to 2%. However, beyond 2%, the overall

K_{i}

decreases again. These changes in

K_{i}

can be explained by the strain-induced variations of Fe 3d orbitals near the Fermi energy. This study provides a comprehensive understanding of the strain effects on magnetic anisotropy in Fe-based heterostructures, offering insights for the further optimization of interfacial magnetic properties. Full article

(This article belongs to the Special Issue Magnetic Materials and Their Applications)

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17 pages, 3948 KiB

Open AccessArticle

Thionitrosyl Complexes of Rhenium and Technetium with PPh₃ and Chelating Ligands—Synthesis and Reactivity

by Domenik Nowak, Adelheid Hagenbach, Till Erik Sawallisch and Ulrich Abram

Inorganics 2024, 12(8), 210; https://doi.org/10.3390/inorganics12080210 - 31 Jul 2024

Cited by 1 | Viewed by 1029

Abstract

In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S₂Cl₂ and (ii) by reaction of [...] Read more.

In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S₂Cl₂ and (ii) by reaction of halide complexes with trithiazyl chloride. The first synthetic route was applied for the synthesis of novel rhenium and technetium thionitrosyls with the metals in their oxidation states “+1” and “+2”. [M^VNCl₂(PPh₃)₂], [M^VNCl(PPh₃)(L^OMe)] and [M^VINCl₂(L^OMe)] (M = Re, Tc; {L^OMe}⁻ = (η⁵-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III)) complexes have been used as starting materials for the synthesis of [Re^II(NS)Cl₃(PPh₃)₂] (1), [Re^II(NS)Cl₃(PPh₃)(OPPh₃)] (2), [Re^II(NS)Cl(PPh₃)(L^OMe)]⁺ (4a), [Re^II(NS)Cl₂(L^OMe)] (5a), [Tc^II(NS)Cl(PPh₃)(L^OMe)]⁺ (4b) and [Tc^II(NS)Cl₂(L^OMe)] (5b). The triphenylphosphine complex 1 is partially suitable as a precursor for ongoing ligand exchange reactions and has been used for the synthesis of [Re^I(NS)(PPh₃)(Et₂btu)₂] (3a) (HEt₂btu = N,N-diethyl-N′-benzoyl thiourea) containing two chelating benzoyl thioureato ligands. The novel compounds have been isolated in crystalline form and studied by X-ray diffraction and spectroscopic methods including IR, NMR and EPR spectroscopy and (where possible) mass spectrometry. A comparison of structurally related rhenium and technetium complexes allows for conclusions about similarities and differences in stability, reaction kinetics and redox behavior between these 4d and 5d transition metals. Full article

(This article belongs to the Special Issue Metal Complexes Diversity: Synthesis, Conformations, and Bioactivity)

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15 pages, 2752 KiB

Open AccessArticle

Physical Vapor Deposition of Indium-Doped GeTe: Analyzing the Evaporation Process and Kinetics

by Andi Zaidan, Vladislava Ivanova and Plamen Petkov

Inorganics 2024, 12(8), 209; https://doi.org/10.3390/inorganics12080209 - 30 Jul 2024

Viewed by 622

Abstract

Chalcogenide glasses have broad applications in the mid-infrared optoelectronics field and as phase-change materials (PCMs) due to their unique properties. Chalcogenide glasses can have crystalline and amorphous phases, making them suitable as PCMs for reversible optical or electrical recording. This study provides an [...] Read more.

Chalcogenide glasses have broad applications in the mid-infrared optoelectronics field and as phase-change materials (PCMs) due to their unique properties. Chalcogenide glasses can have crystalline and amorphous phases, making them suitable as PCMs for reversible optical or electrical recording. This study provides an in-depth analysis of the evaporation kinetics of indium-doped chalcogenides, GeTe₄ and GeTe₅, using the physical vapor deposition technique on glass substrates. Our approach involved a detailed examination of the evaporation process under controlled temperature conditions, allowing precise measurement of rate changes and energy dynamics. This study revealed a significant and exponential increase in the evaporation rate of GeTe₄ and GeTe₅ with the introduction of indium, which was particularly noticeable at higher temperatures. This increase in evaporation rate with indium doping suggests a more complex interplay of materials at the molecular level than previously understood. Furthermore, our findings indicate that the addition of indium affects the evaporation rate and elevates the energy requirements for the evaporation process, providing new insights into the thermal dynamics of these materials. This study’s outcomes contribute significantly to understanding deposition processes, paving the way for optimized manufacturing techniques that could lead to more efficient and higher-performing optoelectronic devices and memory storage solutions. Full article

(This article belongs to the Section Inorganic Materials)

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44 pages, 14415 KiB

Open AccessReview

Towards Construction of the “Periodic Table” of 1-Methylbenzotriazole

by Christina Stamou, Zoi G. Lada, Sophia Paschalidou, Christos T. Chasapis and Spyros P. Perlepes

Inorganics 2024, 12(8), 208; https://doi.org/10.3390/inorganics12080208 - 30 Jul 2024

Cited by 1 | Viewed by 689

Abstract

Metal complexes of benzotriazole-type ligands continue to attract the intense interest of many inorganic chemistry groups around the world for a variety of reasons, including their aesthetically beautiful structures, physical properties and applications. 1-methylbenzotriazole (Mebta) is the N-substituted archetype of the parent [...] Read more.

Metal complexes of benzotriazole-type ligands continue to attract the intense interest of many inorganic chemistry groups around the world for a variety of reasons, including their aesthetically beautiful structures, physical properties and applications. 1-methylbenzotriazole (Mebta) is the N-substituted archetype of the parent 1H-benzotriazole. The first attempt to build a “periodic table” of Mebta, which includes its complexes with several metal ions, is described in this work. This, at first glance, trivial ligand has led to interesting results in terms of the chemistry, structures and properties of its metal complexes. This work reviews the to-date published coordination chemistry of Mebta with Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), Cu(II), Zn(II), Pd(II), Au(I) and {U^VIO₂}²⁺, with emphasis on their preparations, reactivity, structures and properties. Unpublished results from our group comprising other Co(II), Ni(II), Cu(II) and Zn(II) complexes, as well as Cd(II), Hg(II), Ag(I), In(III) and Sn(IV) ones are briefly reported. Mebta can also provide access to 1D and 3D heterometallic thiocyanato-bridged Co(II)/Hg(II) and Ni(II)/Hg(II) compounds. In almost all cases, Mebta behaves as a monodentate ligand with the nitrogen of position 3 of the azole ring as the donor atom. However, there are two copper complexes in which this molecule adopts a bidentate bridging coordination behavior. Our efforts to complete the “periodic table” of Mebta are continued. Full article

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9 pages, 3530 KiB

Open AccessArticle

Investigation of the Dislocation Behavior of 6- and 8-Inch AlGaN/GaN HEMT Structures with a Thin AlGaN Buffer Layer Grown on Si Substrates

by Yujie Yan, Jun Huang, Lei Pan, Biao Meng, Qiangmin Wei and Bing Yang

Inorganics 2024, 12(8), 207; https://doi.org/10.3390/inorganics12080207 - 30 Jul 2024

Viewed by 846

Abstract

Developing cost-effective methods to synthesize large-size GaN films remains a challenge owing to the high dislocation density during heteroepitaxy. Herein, AlGaN/GaN HEMTs were grown on 6- and 8-inch Si(111) substrates using metal–organic chemical vapor deposition, and their basic properties and dislocation evolution characteristics [...] Read more.

Developing cost-effective methods to synthesize large-size GaN films remains a challenge owing to the high dislocation density during heteroepitaxy. Herein, AlGaN/GaN HEMTs were grown on 6- and 8-inch Si(111) substrates using metal–organic chemical vapor deposition, and their basic properties and dislocation evolution characteristics were investigated thoroughly. With the insertion of a 100 nm thin AlGaN buffer layer, bow–warp analysis of the epitaxial wafers revealed excellent stress control for both the 6- and 8-inch wafers. HR-XRD and AFM analyses validated the high crystal quality and step-flow growth mode of GaN. Further, Hall measurements demonstrated the superior transport performance of AlGaN/GaN heterostructures. It is worth noting that dislocations tended to annihilate in the AlN nucleation layer, the thin AlGaN buffer layer, and the GaN buffer layer in the initial thickness range of 200–300 nm, which was indicated by ADF-STEM. To be specific, the heterointerfaces exhibited a significant effect on the annihilation of c-type (b = <0001>) dislocations, which led to the formation of dislocation loops. The thin inserted layers within the AlGaN buffer layer played a key role in promoting the annihilation of c-type dislocations, while they exerted less influence on a-type (b = 1/3<11

\bar{2}

0>) and (a+c)-type (b = 1/3<11

\bar{2}

3>) dislocations. Within an initial thickness of 200–300 nm in the GaN buffer layer, a-type and (a+c)-type dislocations underwent strong interactions, leading to considerable dislocation annihilation. In addition, the EELS results suggested that the V-shaped pits in the AlN nucleation layer were filled with the AlGaN thin layer with a low Al content. Full article

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21 pages, 3800 KiB

Open AccessArticle

New Iron(III)-Containing Composite of Salinomycinic Acid with Antitumor Activity—Synthesis and Characterization

by Juliana Ivanova, Rositsa Kukeva, Radostina Stoyanova, Tanya Zhivkova, Abedulkadir Abudalleh, Lora Dyakova, Radostina Alexandrova, Irena Pashkunova-Martic, Johannes Theiner, Peter Dorkov, Michaela Hejl, Michael A. Jakupec, Bernhard Keppler and Ivo Grabchev

Inorganics 2024, 12(8), 206; https://doi.org/10.3390/inorganics12080206 - 29 Jul 2024

Viewed by 817

Abstract

In this study we demonstrated for the first time synthetic procedures for composites of salinomycin (SalH) and two-line ferrihydrite. The products were characterized by various methods such as elemental analysis, attenuated total reflectance–Fourier-transform spectroscopy (ATR-FTIR), electron paramagnetic resonance spectroscopy (EPR), powder X-ray diffraction [...] Read more.

In this study we demonstrated for the first time synthetic procedures for composites of salinomycin (SalH) and two-line ferrihydrite. The products were characterized by various methods such as elemental analysis, attenuated total reflectance–Fourier-transform spectroscopy (ATR-FTIR), electron paramagnetic resonance spectroscopy (EPR), powder X-ray diffraction analysis (XRD), electrospray-ionization mass spectrometry (ESI-MS), thermogravimetric analysis with differential thermal analysis (DTA) and mass spectrometry (TG-DTA/MS). The EPR spectra of the isolated compounds consisted of signals associated with both isolated Fe³⁺ ions and magnetically coupled Fe³⁺ ions. Powder XRD analyses of the isolated products showed two intense and broad peaks at 9° and 15° 2Θ, corresponding to salinomycinic acid. Broad peaks with very low intensity around 35°, assigned to two-line ferrihydrite, were also registered. Based on the experimental results, we concluded that salinomycin sodium reacted with Fe(III) chloride to form composites consisting of two-line ferrihydrite and salinomycinic acid. One of the composites exerted pronounced antitumor activity in the sub-micromolar concentration range against human cervical cancer (HeLa), non-small-cell lung cancer (A549), colon cancer (SW480), and ovarian teratocarcinoma (CH1/PA1) cells. Full article

(This article belongs to the Section Coordination Chemistry)

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17 pages, 5294 KiB

Open AccessArticle

Designing of High-Performance MnNiS@MXene Hybrid Electrode for Energy Storage and Photoelectrochemical Applications

by Maqsood Ahmad, Muhammad Imran, Amir Muhammad Afzal, Muhammad Ahsan ul Haq, Areej S. Alqarni, Muhammad Waqas Iqbal, Shams A. M. Issa and Hesham M. H. Zakaly

Inorganics 2024, 12(8), 205; https://doi.org/10.3390/inorganics12080205 - 29 Jul 2024

Viewed by 1296

Abstract

The overconsumption of fossil fuels is leading to worsening environmental damage, making the generation of clean, renewable energy an absolute necessity. Two common components of electrochemical energy storage (EES) devices are batteries and supercapacitors (SCs), which are among the most promising answers to [...] Read more.

The overconsumption of fossil fuels is leading to worsening environmental damage, making the generation of clean, renewable energy an absolute necessity. Two common components of electrochemical energy storage (EES) devices are batteries and supercapacitors (SCs), which are among the most promising answers to the worldwide energy issue. In this study, we introduce an exceptionally efficient electrode material for supercapacitors, composed of a hydrothermally synthesized composite known as MnNiS@MXene. We utilized XRD, SEM, and BET to analyze the material’s crystallinity, morphology, and surface area. The Qs of MnNiS@MXene was a remarkable 1189.98 C/g or 1983.3 F/g at 2 A/g under three electrode assemblies in 1 M KOH electrolyte solution. Activated carbon was used as the negative electrode, while MnNiS@MXene served as the positive electrode in the assembled supercapattery device (MnNiS@MXene//AC). This device showed exceptional performance, a specific capacity of 307.18 C/g, a power density of 1142.61 W/kg, and an energy density of 34.79 Wh/kg. Additionally, cyclic durability was evaluated through 7000 cycles of charging/discharging, demonstrating that it maintained approximately 87.57% of its original capacity. The successful integration of these materials can lead to electrodes with superior energy storage capabilities and efficient photoelectrochemical performance. The aforementioned findings suggest that MnNiS@MXene exhibits promising potential as an electrode material for forthcoming energy storage systems. Full article

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15 pages, 8725 KiB

Open AccessArticle

Accomplishment of α-Chymotrypsin on Photodynamic Effect of Octa-Substituted Zn(II)- and Ga(III)-Phthalocyanines against Melanoma Cells

by Vanya Mantareva, Diana Braikova, Neli Vilhelmova-Ilieva, Ivan Angelov and Ivan Iliev

Inorganics 2024, 12(8), 204; https://doi.org/10.3390/inorganics12080204 - 29 Jul 2024

Viewed by 946

Abstract

Octa-methylpyridiloxy-substituted Zn(II)- and Ga(III)-phthalocyanines (ZnPc1 and GaPc1) were studied on human pigmented melanoma (SH4) and keratinocyte (HaCaT) cell lines. The efficacy of ZnPc1 and GaPc1 against melanoma cells was compared to the results in the presence of a proteaseα-chymotrypsin (ChT). The [...] Read more.

Octa-methylpyridiloxy-substituted Zn(II)- and Ga(III)-phthalocyanines (ZnPc1 and GaPc1) were studied on human pigmented melanoma (SH4) and keratinocyte (HaCaT) cell lines. The efficacy of ZnPc1 and GaPc1 against melanoma cells was compared to the results in the presence of a proteaseα-chymotrypsin (ChT). The synthesis and characterization of compounds were carried out using well-known approaches. The formation of physical conjugates due to the addition of ChT was studied via absorption and fluorescence. The proteolytic activity of ChT was verified with casein as a substrate. The photosafety of compounds was proven on embryonal cells (BALB 3T3) under solar exposure (LED 360–1100 nm). The photodynamic activity of GaPc1 and ZnPc1 was studied for a concentration range of irradiation (LED 660 nm). The reduction of the proteolytic activity of ChT was observed only for the irradiation of ZnPc1 or GaPc1. GaPc1 and ChT and their conjugates, except ZnPc1 (PIF ~6), were evaluated as photo-safe to solar light (PIF < 2). The efficiency of GaPc1 was shown to be much higher than that of ZnPc1 in their individual applications. The phototherapeutic index of GaPc1 (PI = 1.71) on SH4 cells was higher for the conjugate. α-Chymotrypsin and phthalocyanine have the advantages of reducing high toxicity and increasing the phototherapeutic index. Full article

(This article belongs to the Special Issue Biological Activity of Metal Complexes)

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19 pages, 11306 KiB

Open AccessArticle

Unveiling the Effect of Solution Concentration on the Optical and Supercapacitive Performance of CoWO₄ Nanoparticles Prepared via the Solvothermal Method

by Sagar M. Mane, Aviraj M. Teli, Sonali A. Beknalkar, Jae Cheol Shin and Jaewoong Lee

Inorganics 2024, 12(8), 203; https://doi.org/10.3390/inorganics12080203 - 29 Jul 2024

Viewed by 877

Abstract

This study explores the influence of solution concentration, specifically that of water and ethylene glycol mixtures, on the optical and supercapacitive properties of cobalt tungstate (CoWO₄) nanoparticles. CoWO₄ nanoparticles were synthesized using varying ratios of water to ethylene glycol to [...] Read more.

This study explores the influence of solution concentration, specifically that of water and ethylene glycol mixtures, on the optical and supercapacitive properties of cobalt tungstate (CoWO₄) nanoparticles. CoWO₄ nanoparticles were synthesized using varying ratios of water to ethylene glycol to ascertain the optimal conditions for enhanced performance. Detailed characterization was conducted using UV–Vis spectroscopy, photoluminescence (PL) spectroscopy, cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) to evaluate the optical properties and electrochemical behavior, respectively. The results revealed that the solution concentration significantly impacted the bandgap, absorbance, and emission properties of the CoWO₄ nanoparticles. Effective bandgap tuning was achieved by altering the solution concentration. When using only water, the nanoparticles displayed the lowest bandgap of 2.57 eV. In contrast, a solution with equal water and ethylene glycol concentrations resulted in the highest bandgap of 2.65 eV. Additionally, the electrochemical studies demonstrated that the water/ethylene glycol ratio markedly influenced the charge storage capacity and cyclic stability of the nanoparticles. The results indicated that the solvent concentration significantly influenced the crystallinity, particle size, and surface morphology of the CoWO₄ nanoparticle nanoparticles, which affected their optical properties and electrochemical performance. Notably, nanoparticles synthesized with a 1.25:0.75 proportion of water to ethylene glycol exhibited superior supercapacitive performance, with a specific capacitance of 661.82 F g⁻¹ at a current density of 7 mA cm⁻² and 106% capacitance retention after 8000 charge–discharge cycles. These findings underscore the critical role of solvent composition in tailoring the functional properties of CoWO₄ nanoparticles, providing insights for their application in optoelectronic devices and energy storage systems. Full article

(This article belongs to the Special Issue Advanced Electrode Materials for Energy Storage Devices)

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15 pages, 1964 KiB

Open AccessArticle

Anti-Cancer Stem Cell Cobalt(III)-Polypyridyl Complexes Containing Salicylic Acid

by Jiaxin Fang, Kuldip Singh and Kogularamanan Suntharalingam

Inorganics 2024, 12(8), 202; https://doi.org/10.3390/inorganics12080202 - 27 Jul 2024

Viewed by 757

Abstract

Metal-containing compounds are an important class of chemotherapeutics used to treat various manifestations of cancer. Despite the widespread clinical use and success of metallopharmaceuticals, they are ineffective towards a sub-population of tumours called cancer stem cells (CSCs). CSCs evade current chemotherapeutic regimens (including [...] Read more.

Metal-containing compounds are an important class of chemotherapeutics used to treat various manifestations of cancer. Despite the widespread clinical use and success of metallopharmaceuticals, they are ineffective towards a sub-population of tumours called cancer stem cells (CSCs). CSCs evade current chemotherapeutic regimens (including metallopharmaceuticals) and promote cancer relapse and metastasis. Here, we report the synthesis, characterisation and anti-breast CSCs properties of a series of cobalt(III)-polypyridyl complexes with salicylic acid. The lead cobalt(III) complex 6 (containing 3,4,7,8-tetramethyl-1,10-phenanthroline) displayed low micromolar potency towards breast CSCs, significantly lower than the gold-standard anti-breast CSC agent, salinomycin, and the clinically used metallodrug, cisplatin. Mechanistic studies indicate that the cobalt(III) complex 6 induces its anti-breast CSC effect by entering breast CSCs, penetrating the nuclei, damaging nuclear DNA and triggering caspase-dependent apoptosis. The cytotoxic mechanism of action of the cobalt(III) complex 6 is also dependent on the modulation of cyclooxygenase-2 (COX-2) expression. This work highlights the anti-breast CSC properties of cobalt(III) coordination complexes with non-steroidal anti-inflammatory drugs (NSAIDs) and more widely spotlights the importance of metallopharmaceuticals in the development of new anticancer agents that can tackle chemotherapeutic-resistant sub-populations. Full article

(This article belongs to the Section Bioinorganic Chemistry)

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15 pages, 3847 KiB

Open AccessArticle

2,1,3-Benzoselenadiazole as Mono- and Bidentate N-Donor for Heteroleptic Cu(I) Complexes: Synthesis, Characterization and Photophysical Properties

by Valentina Ferraro, Fabian Hoffmann, Olaf Fuhr, Burkhard Luy and Stefan Bräse

Inorganics 2024, 12(8), 201; https://doi.org/10.3390/inorganics12080201 - 25 Jul 2024

Viewed by 718

Abstract

Mono- and binuclear Cu(I) complexes were isolated employing 2,1,3-benzoselenadiazole (BSeD) as the N-donor ligand, and triphenylphosphine or bis[(2-diphenylphosphino)phenyl] ether (DPEphos) as P-donors. Then, ⁷⁷Se NMR was measured for the free ligand and the corresponding Cu(I) derivatives, and the related signal was downshifted [...] Read more.

Mono- and binuclear Cu(I) complexes were isolated employing 2,1,3-benzoselenadiazole (BSeD) as the N-donor ligand, and triphenylphosphine or bis[(2-diphenylphosphino)phenyl] ether (DPEphos) as P-donors. Then, ⁷⁷Se NMR was measured for the free ligand and the corresponding Cu(I) derivatives, and the related signal was downshifted by 12.86 ppm in the case of [Cu(BSeD)(PPh₃)₂(ClO₄)], and around 15 ppm for the binuclear species. The structure of [Cu(BSeD)(PPh₃)₂(ClO₄)] and [Cu₂(μ₂-BSeD)(DPEphos)₂(ClO₄)₂] was confirmed by single-crystal X-ray diffraction. The geometry of the Cu(I) complexes was optimized through DFT calculations, and the nature of the Cu···O interaction was investigated through AIM analysis. The three Cu(I) complexes were characterized by intense absorption under 400 nm and, after being excited with blue irradiation, [Cu(BSeD)(PPh₃)₂(ClO₄)] and [Cu₂(μ₂-BSeD)(PPh₃)₄(ClO₄)₂] exhibited weak red emissions centered at 700 nm. The lifetimes comprised between 121 and 159 μs support the involvement of triplet excited states in the emission process. The photoluminescent properties of [Cu(BSeD)(PPh₃)₂(ClO₄)] were supported by TDDFT computations, and the emission was predicted at 710 nm and ascribed to a metal-to-ligand charge transfer (³MLCT) process, in agreement with the experimental data. Full article

(This article belongs to the Special Issue State-of-the-Art Inorganic Chemistry in Germany)

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