Inorganics

16 pages, 4035 KiB

Open AccessArticle

Realizing Environmentally Scalable Pre-Lithiation via Protective Coating of LiSi Alloys to Promote High-Energy-Density Lithium-Ion Batteries

by Yinan Liu, Wei Jiang, Congcong Zhang, Pingshan Jia, Zhiyuan Zhang, Yun Zheng, Kunye Yan, Jun Wang, Yunxian Qian, Junpo Guo, Rong Chen, Yike Huang, Yingying Shen, Lifen Long, Bang Zheng and Huaiyu Shao

Inorganics 2025, 13(4), 115; https://doi.org/10.3390/inorganics13040115 (registering DOI) - 6 Apr 2025

Abstract

Pre-lithiation using Li–Si alloy-type additives is a promising technical approach to address the drawbacks of Si-based anodes, such as a low initial Coulombic efficiency (ICE) and inevitable capacity decay during cycling. However, its commercial application is limited by the air sensitivity of the [...] Read more.

Pre-lithiation using Li–Si alloy-type additives is a promising technical approach to address the drawbacks of Si-based anodes, such as a low initial Coulombic efficiency (ICE) and inevitable capacity decay during cycling. However, its commercial application is limited by the air sensitivity of the highly reactive Li–Si alloys, which demands improved environmental stability. In this work, a protective membrane is constructed on Li₁₃Si₄ alloys using low-surface-energy paraffin and highly conductive carbon nanotubes through liquid-phase deposition, exhibiting enhanced hydrophobicity and improved Li⁺/e⁻ conductivity. The Li₁₃Si₄@Paraffin/carbon nanotubes (Li₁₃Si₄@P-CNTs) composite achieves a high pre-lithiation capacity of 970 mAh g⁻¹ and superb environmental stability, retaining 92.2% capacity after exposure to ambient air with 45% relative humidity. DFT calculations and in situ XRD measurements reveal that the paraffin-dominated coating membrane, featuring weak dipole–dipole interactions with water molecules, effectively reduces the moisture-induced oxidation kinetics of Li₁₃Si₄@P-CNTs in air. Electrochemical kinetic analysis and XPS depth profiling reveal the enhancement in charge transfer dynamics and surface Li⁺ transport kinetics (SEI rich in inorganic lithium salts) in P-SiO@C pre-lithiated by Li₁₃Si₄@P-CNTs pre-lithiation additives. Benefitting from pre-lithiation via Li₁₃Si₄@P-CNTs, the pre-lithiated SiO@C(P-SiO@C) delivers high ICE (103.7%), stable cycling performance (981 mAh g⁻¹ at 200 cycles) and superior rate performance (474.5 mAh g⁻¹ at 3C) in a half-cell system. The LFP||P-Gr pouch-type full cell exhibits a capacity retention of 83.2% (2500 cycles) and an energy density of 381 Wh kg⁻¹ after 2500 cycles. The Li₁₃Si₄@P-CNTs additives provide valuable design concepts for the development of pre-lithiation materials. Full article

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

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17 pages, 5778 KiB

Open AccessArticle

Adsorption of CuSO₄ on Anatase TiO₂ (101) Surface: A DFT Study

by Frank Maldonado, Darwin Castillo, Silvio Aguilar, Javier Carrión and Aramis Sánchez

Inorganics 2025, 13(4), 114; https://doi.org/10.3390/inorganics13040114 (registering DOI) - 5 Apr 2025

Abstract

The rapid growth of industrial activities has increased environmental pollution, and solar-driven heterogeneous photocatalysis using TiO₂ has emerged as a promising solution. However, its wide band gap limits its efficiency, prompting research into various optimization strategies. One of these approaches is surface [...] Read more.

The rapid growth of industrial activities has increased environmental pollution, and solar-driven heterogeneous photocatalysis using TiO₂ has emerged as a promising solution. However, its wide band gap limits its efficiency, prompting research into various optimization strategies. One of these approaches is surface functionalization. Thus, this study investigates the adsorption of CuSO₄ on the anatase TiO₂ (101) surface using density functional theory calculations. The adsorption process induced a magnetic moment of 0.97 µ_B and a slight reduction in overall bandwidth. A preferential adsorption geometry pattern with an energy of −4.31 eV was identified. Charge transfer analysis revealed a net transfer from the TiO₂ surface to the CuSO₄ molecule, with increased net atomic charges for atoms involved in new chemical bond formation, indicating a chemisorption process. These electronic structure modifications are expected to influence the electronic and catalytic properties of the material. The findings provide insights into the CuSO₄ adsorption mechanism on an anatase TiO₂ (101) surface and its impact on the properties of the material, contributing to a deeper understanding of this system. Full article

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17 pages, 10207 KiB

Open AccessArticle

Synthesis of Multiwalled Carbon Nanotubes on Different Cobalt Nanoparticle-Based Substrates

by Nicolas Moreau, Antonio Fonseca, Danilo Vuono, Joseph Delhalle, Zineb Mekhalif, Pierantonio De Luca and Janos B.Nagy

Inorganics 2025, 13(4), 113; https://doi.org/10.3390/inorganics13040113 - 3 Apr 2025

Abstract

The primary aim of this research was to identify the optimal experimental conditions for obtaining aligned carbon nanotubes, temporarily leaving aside aspects such as the purity of carbon nanotubes, which is nonetheless crucial for potential applications in the field of nanoelectronics. The predefined [...] Read more.

The primary aim of this research was to identify the optimal experimental conditions for obtaining aligned carbon nanotubes, temporarily leaving aside aspects such as the purity of carbon nanotubes, which is nonetheless crucial for potential applications in the field of nanoelectronics. The predefined alignment of CNTs can significantly influence the performance and efficiency of electronic components. In this study, two different catalytic supports based on cobalt nanoparticles, Co/SiO₂/Si and Co/C, have been utilized and compared in the catalytic chemical vapor deposition (CCVD) synthesis of CNTs. Various parameters have been examined, including the nature and thickness of the catalyst, the reaction temperature, and the pressure of the acetylene mixture entering the reactor. The results indicate that the optimal temperature for the Co/SiO₂/Si catalyst is 800 °C, while for the Co/C catalyst, it is 450 °C. The optimal Co layer thickness should be between 20 and 30 Å. CNT growth occurs from the top in the Co/C system, whereas bottom-up growth is characteristic of the Co/SiO₂/Si catalyst, making the latter more suitable for the synthesis of CNTs intended for nanoelectronic devices. Full article

(This article belongs to the Special Issue Carbon-Based Hybrid Materials for Environmental and Energy Applications)

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24 pages, 7829 KiB

Open AccessArticle

Facile Synthesis and Characterization of SrCO₃/MgO/CaO/CaCO₃ Novel Nanocomposite for Efficient Removal of Crystal Violet Dye from Aqueous Media

by Ehab A. Abdelrahman and Maram T. Basha

Inorganics 2025, 13(4), 112; https://doi.org/10.3390/inorganics13040112 - 3 Apr 2025

Abstract

Crystal violet dye poses significant environmental and human health risks due to its toxicity, persistence, and bioaccumulative nature. It contributes to potential carcinogenicity, cytotoxicity, and systemic toxicity upon human exposure. To address this issue, a novel SrCO₃/MgO/CaO/CaCO₃ nanocomposite was synthesized [...] Read more.

Crystal violet dye poses significant environmental and human health risks due to its toxicity, persistence, and bioaccumulative nature. It contributes to potential carcinogenicity, cytotoxicity, and systemic toxicity upon human exposure. To address this issue, a novel SrCO₃/MgO/CaO/CaCO₃ nanocomposite was synthesized using the Pechini sol-gel method, producing AE500 and AE700 at 500 and 700 °C, respectively, for the efficient removal of crystal violet dye from aqueous media. X-ray diffraction (XRD) analysis confirmed the formation of crystalline phases, with average crystallite sizes of 64.53 nm for AE500 and 75.34 nm for AE700. Energy-dispersive X-ray spectroscopy (EDX) revealed elemental compositions with variations in carbon, oxygen, magnesium, calcium, and strontium percentages influenced by synthesis temperature. Field-emission scanning electron microscopy (FE-SEM) showed morphological differences, where AE500 had irregular polyhedral structures, while AE700 exhibited more compact spherical formations, with average grain sizes of 99.98 and 132.23 nm, respectively. High-resolution transmission electron microscopy (HR-TEM) confirmed the structural integrity and nano-scale morphology, showing aggregated irregularly shaped particles in AE500, while AE700 displayed well-defined polyhedral and nearly spherical nanoparticles. The calculated average particle diameters were 21.67 nm for AE500 and 41.19 nm for AE700, demonstrating an increase in particle size with temperature. Adsorption studies demonstrated maximum capacities of 230.41 mg/g for AE500 and 189.39 mg/g for AE700. The adsorption process was exothermic, spontaneous, and physical, following the pseudo-first-order kinetic model and Langmuir isotherm, indicating monolayer adsorption onto a homogenous surface. Full article

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15 pages, 2726 KiB

Open AccessArticle

Electrochemical Quartz Microbalance for Studying Electrodeposited Pt Catalysts for Methanol Oxidation Reaction

by Bangfeng Zong, Xiaojun Pan, Bo Wei, Lifang Zhang, Xiangxiong Feng, Chenggong Hou, Hai Yan, Wenju Xie, Guicheng Liu and Feng Ye

Inorganics 2025, 13(4), 111; https://doi.org/10.3390/inorganics13040111 - 3 Apr 2025

Abstract

Pt catalysts are investigated for methanol oxidation in direct methanol fuel cells, utilizing the electrochemical quartz microbalance method (EQCM) with exceptional resolution and sensitivity. Pt catalysts were deposited onto the gas-diffusion layer of carbon using stationary potential electrodeposition. Physical characterization and electrochemical tests [...] Read more.

Pt catalysts are investigated for methanol oxidation in direct methanol fuel cells, utilizing the electrochemical quartz microbalance method (EQCM) with exceptional resolution and sensitivity. Pt catalysts were deposited onto the gas-diffusion layer of carbon using stationary potential electrodeposition. Physical characterization and electrochemical tests were performed. SEM results showed that Pt presented dendrite crystals with nanoscale facets. Cyclic voltammetry (CV) demonstrated that the current density for the methanol oxidation reaction highly reached 1020 mA·cm⁻² for the deposited Pt catalyst by EQCM. The dendrite crystal structures of deposited Pt provide much area for high catalytic activity. It found that the peak density of the Pt catalysts for the methanol oxidation reaction decreased after five cycles. Furthermore, the response frequency for the adsorption of the deposited Pt catalysts was investigated using EQCM and compared with commercial PtRu catalysts. The results showed that the response frequency of the Pt catalysts decreased more rapidly than that of the PtRu catalysts. It is possible for the adsorption of small organic molecules on Pt catalysts to occur during the methanol electro-oxidation with CO_ad intermediates. The reaction mechanism is preliminarily discussed by the electrochemical measurement combined with EQCM. Full article

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6 pages, 205 KiB

Open AccessEditorial

Featured Papers in Inorganic Materials 2024

by Roberto Nisticò and Torben R. Jensen

Inorganics 2025, 13(4), 110; https://doi.org/10.3390/inorganics13040110 - 2 Apr 2025

Abstract

After the impressive success of the Special Issue “10th Anniversary of Inorganics: Inorganic Materials”, published in 2023 [...] Full article

(This article belongs to the Special Issue Featured Papers in Inorganic Materials 2024)

20 pages, 6163 KiB

Open AccessArticle

Copper Methacrylate Complexes with Benzimidazole Derivatives: Structural Characterization and Antimicrobial Assays

by Andra-Georgeta Andrei, Rodica Olar, Cătălin Maxim, Gina Vasile Scăețeanu, Ioana-Cristina Marinas, Madalina-Diana Gaboreanu and Mihaela Badea

Inorganics 2025, 13(4), 109; https://doi.org/10.3390/inorganics13040109 - 1 Apr 2025

Abstract

In order to design antimicrobial species, a series of methacrylate (Macr) complexes, [Cu(HBzIm)₂(Macr)₂] (1), [Cu₂(HBzIm)₂(Macr)₄] (2), [Cu(2-MeBzIm)₂(Macr)₂] (3), [Cu₂(2-MeBzIm)₂(Macr) [...] Read more.

In order to design antimicrobial species, a series of methacrylate (Macr) complexes, [Cu(HBzIm)₂(Macr)₂] (1), [Cu₂(HBzIm)₂(Macr)₄] (2), [Cu(2-MeBzIm)₂(Macr)₂] (3), [Cu₂(2-MeBzIm)₂(Macr)₄] (4), and [Cu(5,6-Me₂BzIm)₂(Macr)₂] (5) (HBzIm = benzimidazole, 2-MeBzIm = 2-methylbenzimidazole, and 5,6-Me₂BzIm = 5,6-dimethylbenzimidazole) were synthesized and characterized by several spectral techniques, as well as by single crystal X-ray diffraction. The mononuclear species exhibit a distorted octahedral stereochemistry, while the binuclear types, with a paddle-wheel structure, adopt a square pyramidal surrounding. The methacrylate acts either as a chelate or a bridge, while all benzimidazole derivatives are coordinated as unidentate. The supramolecular networks are developed by both intermolecular π–π stacking interactions and hydrogen bonds. The antimicrobial assays provided both complexes the ability to inhibit planktonic strain proliferation, as well as to adhere on inert substratum. All complexes exhibit a moderate antimicrobial activity, both in regards to standard and clinical isolate strains, the most active being compound 5 against Candida albicans, with a minimum inhibitory concentration (MIC) of 0.156 mg/mL. It is worth mentioning that complex 1 inhibited the microbial adhesion of the clinical Escherichia coli strain and complex 2 constrained that of the clinical C. albicans strain. Full article

(This article belongs to the Special Issue Metal Complexes with N-donor Ligands, 2nd Edition)

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18 pages, 4833 KiB

Open AccessArticle

Achieving Ultralong Room-Temperature Phosphorescence in Two-Dimensional Metal-Halide Perovskites by Tuning Alkyl Chain Length

by Suqin Wang, Hui Zhu, Ming Sheng, Bo Shao, Yu He, Zhuang Liu, Min Li and Guangtao Zhou

Inorganics 2025, 13(4), 108; https://doi.org/10.3390/inorganics13040108 - 1 Apr 2025

Abstract

Two-dimensional (2D) metal-halide perovskites with highly efficient room-temperature phosphorescence (RTP) are rare due to their complex structures and intricate intermolecular interactions. In this study, by varying the alkyl chain length in organic amines, we synthesized two 2D metal-halide perovskites, namely 4-POMACC and 4-POEACC, [...] Read more.

Two-dimensional (2D) metal-halide perovskites with highly efficient room-temperature phosphorescence (RTP) are rare due to their complex structures and intricate intermolecular interactions. In this study, by varying the alkyl chain length in organic amines, we synthesized two 2D metal-halide perovskites, namely 4-POMACC and 4-POEACC, both of which exhibit significant RTP emission. Notably, 4-POMACC demonstrates a stronger green RTP emission with a significantly longer lifetime (254 ms) and a higher photoluminescence quantum yield (9.5%) compared to 4-POEACC. A thorough investigation of structural and optical properties reveals that shorter alkyl chains can enhance the optical performance due to reduced molecular vibrations and more effective exciton recombination. Computational calculations further show that the smaller energy gap between S₁ and T_n in 4-POMA facilitates intersystem crossing, thereby improving RTP performance. Based on their remarkable phosphorescence properties, we demonstrated their applications in information encryption. This work offers a novel design strategy that could inspire the development of next-generation RTP materials. Full article

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

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9 pages, 1114 KiB

Open AccessArticle

Electrical Features of Liquid Crystal Composition Doped with Cobalt Ferrite: Possible Sensing Applications

by Yaroslav Barnash, Sonja Jovanović, Zoran Jovanović and Natalia Kamanina

Inorganics 2025, 13(4), 107; https://doi.org/10.3390/inorganics13040107 - 28 Mar 2025

Abstract

The effects of CoFe₂O₄ nanoparticles on the properties of an electro-optical liquid crystal cell based on the nematic composition of 4-Cyano-4′-pentylbiphenyl (5CB) under the influence of different forms of bias voltage were studied. Detailed results were established for the application [...] Read more.

The effects of CoFe₂O₄ nanoparticles on the properties of an electro-optical liquid crystal cell based on the nematic composition of 4-Cyano-4′-pentylbiphenyl (5CB) under the influence of different forms of bias voltage were studied. Detailed results were established for the application of sinusoidal voltages with various frequencies and amplitudes. At the input signal, with a frequency of 500 kHz, a resonant current increase was obtained in the electrical circuit, followed by a decrease in the current with an increase in the frequency. This indicates the formation of a consistent oscillatory circuit. The quality factor of the nanoparticle system does not depend on the amplitude of the controlled voltage. Liquid crystal cells with constant quality can be used in a number of devices and technologies, including extended sensing devices, where stable electrical properties are required. Full article

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

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25 pages, 5688 KiB

Open AccessArticle

Correlating the Characteristics and Catalytic Performance of Mn-Na-W-O_x/SiO₂ for Oxidative Coupling of Methane

by Hamid Reza Godini, Stefan Berendts, Rafael Kleba-Ehrhardt, Asma Tufail Shah and Oliver Görke

Inorganics 2025, 13(4), 106; https://doi.org/10.3390/inorganics13040106 - 28 Mar 2025

Abstract

Chemical–structural characteristics of three differently synthesized research-benchmark Mn-Na-W-O_x/SiO₂ catalysts for the Oxidative Coupling of Methane (OCM) were systematically studied in this research. XRD, EDX, ICP-OES, and SEM/FIB-SEM techniques, as well as Carrier Gas Hot Extraction (CGHE) and high-temperature XRD analyses, [...] Read more.

Chemical–structural characteristics of three differently synthesized research-benchmark Mn-Na-W-O_x/SiO₂ catalysts for the Oxidative Coupling of Methane (OCM) were systematically studied in this research. XRD, EDX, ICP-OES, and SEM/FIB-SEM techniques, as well as Carrier Gas Hot Extraction (CGHE) and high-temperature XRD analyses, were performed to explain the functional features of the studied catalysts, in particular, the features affecting the quantity and quality of the interactions of oxygen and methane with the catalyst surface and with other molecular and radical species. These enable tracking the potential for the oxygen activation and dynamic transformation of the solid-state chemistry on the surface and sub-surface of these Mn-Na-W-O_x/SiO₂ catalysts. These catalysts were synthesized, respectively, via the sol–gel synthesis method (Cat₁) and the incipient wetness impregnation of the non-structured silica support (Cat₂) and structured SBA-15 silica support (Cat₃), under different sets of temperatures and gas compositions. The catalysts with the homogenous distribution of active components, namely Cat₁ and Cat₃, showed similar trends in terms of their dynamic interaction with oxygen species. They also showed higher levels of crystallinity of the active materials and higher catalytic selectivity towards ethane and ethylene. An explanation is given as to how the structural characteristics of the catalysts on the nanometer–micrometer scale contribute to these. The gained knowledge will be crucial in the selection and treatment of the support and developing a proper synthesis approach for the ultimate goal of designing a selective OCM catalyst. Full article

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17 pages, 6481 KiB

Open AccessArticle

Enhanced Antimicrobial and Biomedical Properties of Fe-Based Bulk Metallic Glasses Through Ag Addition

by Long Jiang, Xueru Fan, Qiang Li, Xin Li, Tao Jiang and Qin Wei

Inorganics 2025, 13(4), 105; https://doi.org/10.3390/inorganics13040105 - 28 Mar 2025

Abstract

This study explores the enhancement of antimicrobial and biomedical properties in Fe-based bulk metallic glasses (BMGs) through the addition of Ag. Fe_55-xCr₂₀Mo₅P₁₃C₇Ag_x (x = 0, 1, 2, 3 at.%) master alloy ingots [...] Read more.

This study explores the enhancement of antimicrobial and biomedical properties in Fe-based bulk metallic glasses (BMGs) through the addition of Ag. Fe_55-xCr₂₀Mo₅P₁₃C₇Ag_x (x = 0, 1, 2, 3 at.%) master alloy ingots were synthesized by the induction melting technique and industrial-grade raw materials, the master alloy ingots were prepared as bulk metallic glasses (referred to as Ag0, Ag1, Ag2, and Ag3) by the water-cooled copper-mold suction casting technique, and their glass-forming ability, corrosion resistance, biocompatibility, and antimicrobial properties were systematically investigated. The results indicate that the glass forming ability (GFA) decreased with increasing Ag content, reducing the critical diameter for fully amorphous formation from 2.0 mm for Ag0 to 1.0 mm for Ag3. Electrochemical tests in Hank’s solution revealed the superior corrosion resistance of the Fe-based BMGs as compared with conventional 316 L stainless steel (316L SS) and Ti6Al4V alloy (TC4), with Ag3 demonstrating the lowest corrosion current density and the most stable passivation. Biocompatibility assessments, including fibroblast cell viability and adhesion tests, showed enhanced cellular activity and morphology on Fe-based BMG surfaces as compared with 316L SS and TC4, with minimal harmful ion release. Antimicrobial tests against E. coli and S. aureus revealed significantly improved performance with the Ag addition, achieving bacterial inhibition rates of up to 87.5% and 86.7%, respectively, attributed to Ag⁺-induced reactive oxygen species (ROS) production. With their excellent corrosion resistance, biocompatibility, and antimicrobial activity, the present Ag-containing Fe-based BMGs, particularly Ag3, are promising candidates for next-generation biomedical implants. Full article

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

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13 pages, 4848 KiB

Open AccessArticle

Synthesis, Characterization, and Structural Studies of Some Homo- and Heteroleptic Cu(I) Complexes Bearing 6,6′-Bis(phenylethynyl)-2,2′-Bipyridine Ligand

by Rayya A. Al-Balushi, Md. Serajul Haque Faizi, Md. Mushtaque, Idris J. Al-Busaidi and Muhammad S. Khan

Inorganics 2025, 13(4), 104; https://doi.org/10.3390/inorganics13040104 - 28 Mar 2025

Abstract

Coordination-driven Cu(I) complexes constitute an interesting class of materials with rich opto-electronic properties and diverse applications. Various homo- and heteroleptic Cu(I) complexes have been reported in the literature. In continuation with our quest for new materials, we report herein two novel coordination-driven self-assembled [...] Read more.

Coordination-driven Cu(I) complexes constitute an interesting class of materials with rich opto-electronic properties and diverse applications. Various homo- and heteroleptic Cu(I) complexes have been reported in the literature. In continuation with our quest for new materials, we report herein two novel coordination-driven self-assembled Cu(I) complexes: the homoleptic (1) and the heteroleptic (2) complexes based on the 6,6′-bis(phenylethynyl)-2,2′-bipyridine (L1) and 2,9-dimethyl-1,10-phenanthroline (dmph) ligands. L1 was prepared by a Pd(II)-catalyzed Sonogashira cross-coupling reaction between phenylactylene and 6,6′-dibromo-2,2′-bipyridine. Homo- and heteroleptic Cu(I) complexes were obtained by the self-assembly of L1 and dmph ligands. Complexes (1) and (2) were obtained in high yields, and are soluble in common organic solvents and stable at room temperature over a long period of time. The optical (absorption and emission) properties of both complexes were evaluated. The optical properties in solution are a function of the ligands and varied for the complexes. Complex (2) was also characterized by single-crystal X-ray diffraction and the intermolecular interaction was studied using Hirschfeld surface analysis. In the solid state, complex (2) exhibited four-coordinate distorted tetrahedral geometry around Cu(I). Density functional theory (B3LYP/6-311++G(d,p) was utilised to determine various molecular descriptors. Full article

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18 pages, 6689 KiB

Open AccessReview

Classification, Functions, Development and Outlook of Photoanode Block Layer for Dye-Sensitized Solar Cells

by Youqing Wang, Wenxuan Wu and Peiling Ren

Inorganics 2025, 13(4), 103; https://doi.org/10.3390/inorganics13040103 - 27 Mar 2025

Abstract

The block layer situated between the active material and electrode in photoelectrochemical devices serves as a critical component for performance enhancement. Using dye-sensitized solar cells as a representative model, this review systematically examines the strategic positioning and material selection criteria of block layers [...] Read more.

The block layer situated between the active material and electrode in photoelectrochemical devices serves as a critical component for performance enhancement. Using dye-sensitized solar cells as a representative model, this review systematically examines the strategic positioning and material selection criteria of block layers following a concise discussion of their fundamental mechanisms. We categorize block layer architectures into three distinct configurations: single layer, doped layer, and multilayer structures. The electron generation and transport mechanisms to photoelectrodes are analyzed through structural design variations across these configurations. Through representative literature examples, we demonstrate the correlation between material properties and photoconversion efficiency, accompanied by comprehensive performance comparisons. In the single-layer section, we comparatively evaluate the merits and limitations of TiO₂- and ZnO-based block layers. The doped layer discussion traces the evolutionary trajectory from single-dopant systems to co-doping strategies. For multilayer architectures, we elaborate on the flexibility of its functional regulation. Finally, we present a forward-looking perspective on the hot issues that need to be urgently addressed in photoelectrochemical device block layers. Full article

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13 pages, 4020 KiB

Open AccessArticle

Investigation on the Electron Emission Regularity of Sputtered Boron Nitride Thin Films and Microstructured Array Surfaces

by Yuqing Gu, Juannan Li and Dan Wang

Inorganics 2025, 13(4), 102; https://doi.org/10.3390/inorganics13040102 - 26 Mar 2025

Abstract

Boron nitride (BN) ceramic is an important support material in aerospace, arc discharge devices, and vacuum electronics. The electron emission properties of BN surfaces are of significance among various space applications. In this work, by preparing BN thin films and microstructured BN bulks, [...] Read more.

Boron nitride (BN) ceramic is an important support material in aerospace, arc discharge devices, and vacuum electronics. The electron emission properties of BN surfaces are of significance among various space applications. In this work, by preparing BN thin films and microstructured BN bulks, we have investigated the influence of the surface physical properties on the electron emission coefficient (EEC). The results showed that the surfaces of BN films, which were prepared by magnetron sputtering, produced serious gas adsorption and organic contamination when they were left for 10 days, and these surface modifications made the EEC of BN film surface decrease to a certain extent. The argon ion cleaning experiments indicated that the process of ion cleaning was able to partly eliminate the surface adsorption and contamination for the BN film. The EEC of the cleaned BN film surface was significantly improved compared to that of the original polluted BN film surface, with an EEC peak value of about 3.2 instead of 3.0 for the original polluted surfaces. By contrast, the EEC curves of the BN bulk show some difference, with the peak values of the EEC curves being 2.62 for the untreated BN bulk. The results of laser etching on the BN bulk surface to form microarray structures show that the EEC of BN bulk decreases significantly with the increase of the average aspect ratio of the microstructures. The EEC peak values of the BN bulks decrease from 2.62 to 1.16 when the porosity of the BN bulk reaches 49.11% and the aspect ratio reaches 1.36, indicating that constructing a surface microstructure is an effective method to achieve EEC reduction. By employing the electron trajectory tracking algorithm and the phenomenological model of electron emission, the effect of microstructure on EEC for BN bulk was quantitatively explained. The results of the study are of engineering application significance for vacuum devices involving the electron emission process of BN ceramic. Full article

(This article belongs to the Special Issue Boron-Based Low-Dimensional Nanoclusters and Nanomaterials)

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25 pages, 7246 KiB

Open AccessArticle

Facile Synthesis and Characterization of Novel CoFe₂O₄@MgO@(Mg_0.23Co_0.77)(Mg_0.35Co_1.65)O₄@C and CoFe₂O₄@MgO@C Nanocomposites for Efficient Removal of Zn(II) Ions from Aqueous Media

by Ehab A. Abdelrahman, Reem K. Shah, Mortaga M. Abou-Krisha, Fawaz A. Saad and Abdalla M. Khedr

Inorganics 2025, 13(4), 101; https://doi.org/10.3390/inorganics13040101 - 23 Mar 2025

Abstract

Excessive levels of Zn(II) ions in aquatic environments pose significant risks to both ecosystems and human health. In aquatic systems, Zn(II) ions disrupt metabolic functions in organisms, leading to toxicity and bioaccumulation. For humans, prolonged exposure can result in gastrointestinal distress, immune system [...] Read more.

Excessive levels of Zn(II) ions in aquatic environments pose significant risks to both ecosystems and human health. In aquatic systems, Zn(II) ions disrupt metabolic functions in organisms, leading to toxicity and bioaccumulation. For humans, prolonged exposure can result in gastrointestinal distress, immune system dysfunction, and neurological complications, necessitating effective removal strategies. This study reports the synthesis and characterization of CoFe-MgO-C-M600 (CoFe₂O₄@MgO@(Mg_0.23Co_0.77)(Mg_0.35Co_1.65)O₄@C) and CoFe-MgO-C-M800 (CoFe₂O₄@MgO@C) nanocomposites for the efficient removal of Zn(II) ions from aqueous media. The nanocomposites were synthesized using the Pechini sol-gel method and characterized through X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). XRD analysis confirmed the crystalline structure of both nanocomposites, with CoFe-MgO-C-M600 exhibiting a smaller average crystallite size (38.67 nm) than CoFe-MgO-C-M800 (75.48 nm). EDX results verified the elemental composition of the nanocomposites, ensuring the successful incorporation of key elements. FE-SEM analysis revealed significant morphological differences, with CoFe-MgO-C-M600 displaying smaller and more uniform grains compared to CoFe-MgO-C-M800. The results show that CoFe-MgO-C-M600 possesses a highly porous and interconnected structure, enhancing its surface area and adsorption potential. In contrast, CoFe-MgO-C-M800 demonstrates larger and more compact grains, which may affect its adsorption performance. HR-TEM further confirmed these findings, demonstrating that CoFe-MgO-C-M600 had a smaller average particle diameter (35.45 nm) than CoFe-MgO-C-M800 (321.14 nm). Adsorption studies indicated that CoFe-MgO-C-M600 and CoFe-MgO-C-M800 achieved maximum adsorption capacities of 276.24 and 200.00 mg/g, respectively. The adsorption process was determined to be exothermic, spontaneous, and physical in nature, following the pseudo-second-order kinetic model and the Langmuir isotherm. Full article

(This article belongs to the Special Issue Organic–Inorganic Nanocomposites for Water Treatment)

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29 pages, 4913 KiB

Open AccessReview

Comparative B3PW and B3LYP Calculations of ABO₃ (A = Ba, Sr, Pb, Ca; B = Sn, Ti, Zr) Neutral (001) and Polar (111) Surfaces

by Roberts I. Eglitis, Juris Purans, Ran Jia, Sergei P. Kruchinin and Steffen Wirth

Inorganics 2025, 13(4), 100; https://doi.org/10.3390/inorganics13040100 - 23 Mar 2025

Abstract

We completed B3LYP and B3PW computations for AO- and BO₂-terminated (001) as well as AO₃- and B-terminated (111) surfaces of BSO, BTO, STO, PTO, CTO, BZO, SZO, and CZO perovskites. In particular, we performed the first B3LYP computations for [...] Read more.

We completed B3LYP and B3PW computations for AO- and BO₂-terminated (001) as well as AO₃- and B-terminated (111) surfaces of BSO, BTO, STO, PTO, CTO, BZO, SZO, and CZO perovskites. In particular, we performed the first B3LYP computations for polar BSO (111) surfaces. We observed that most of the upper-layer atoms for AO- and BO₂-terminated ABO perovskite (001) surfaces relax inward. In contrast, practically all second-layer atoms relax upward. Lastly, almost all third-layer atoms relax inward. This tendency is less pronounced for atomic relaxation of first, second, and third layer atoms for AO₃- and B-terminated ABO perovskite (111) surfaces. For almost all ABO perovskites, their (001) surface rumplings s are considerably larger for AO-terminated compared to BO₂-terminated surfaces. On the contrary, the ABO perovskite (001) surface energies, for both AO and BO₂-terminations, are essentially equivalent. The ABO perovskite polar (111) surface energies are always substantially larger than their neutral (001) surface energies. In most cases, the surface energies of AO₃-terminated ABO perovskite polar (111) surfaces are considerably larger than their B-terminated surface energies. Our computations illustrate a noticeable boost in the B-O bond covalency near the BO₂-terminated (001) surface related to the bulk. Our computed ABO perovskite bulk Γ-Γ band gaps are almost always reduced near the AO- and BO₂-terminated neutral (001) surfaces as well as in most cases also near the AO₃- and B-terminated polar (111) surfaces. Full article

(This article belongs to the Special Issue Optical and Quantum Electronics: Physics and Materials)

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11 pages, 2252 KiB

Open AccessArticle

Effects of Zn Doping on Optical Properties of Polycrystalline β-Ga₂O₃

by Yue Yan, Shuai Zhu, Jing Yang, Yuanyuan Zhang, Wei Bai and Xiaodong Tang

Inorganics 2025, 13(4), 99; https://doi.org/10.3390/inorganics13040099 - 22 Mar 2025

Abstract

In this study, Zn-doped Ga₂O₃ polycrystalline samples were prepared by solid-phase sintering, and the effects of Zn doping on the optical properties of Ga₂O₃ were investigated. It is found that the introduced Zn ions disrupted the Ga-O [...] Read more.

In this study, Zn-doped Ga₂O₃ polycrystalline samples were prepared by solid-phase sintering, and the effects of Zn doping on the optical properties of Ga₂O₃ were investigated. It is found that the introduced Zn ions disrupted the Ga-O bonds and formed Zn_Ga, altering the Ga-O vibration modes and causing a blue shift in the related Raman mode. From near-infrared to visible light-range was a transparent region for Zn-doped Ga₂O₃. The fundamental optical bandgap underwent a decrease with increasing Zn doping content, primarily due to the p-d orbital hybridization of the O 2p and Zn 3d orbitals causing an upward shift valence band maximum and band renormalization effect-induced band-tails. The recombination of electrons at donor levels (V_O) and holes at acceptor levels (V_Ga or V_O-V_Ga) gave rise to blue-green luminescence. Zn doping increased the concentration oxygen vacancies (V_O), resulting in significant blue-green luminescence enhancement in Zn-doped Ga₂O₃. Additionally, Zn doping resulted in a noticeable reduction in the red luminescence of Ga₂O₃, which may be attributed to Zn doping suppressing nitrogen incorporation from the air during high-temperature preparation processes. Full article

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13 pages, 1920 KiB

Open AccessReview

Research Progress on Graphene Oxide (GO)/Chitosan (CS) Multifunctional Nanocomposites for Drug Delivery

by Yanqiu Hu, Lei Ma, Qi Shi, Jinghang Li, Yuguang Lv and Chaoyu Song

Inorganics 2025, 13(4), 98; https://doi.org/10.3390/inorganics13040098 - 21 Mar 2025

Abstract

With the unprecedented progress of biomedical nanotechnology in the past few decades, traditional drug delivery systems (DDSs) have been incorporated into intelligent DDSs with stimulus responsive characteristics. Graphene oxide (GO) and Chitosan (CS) have excellent physical, chemical, mechanical, and optical properties, and their [...] Read more.

With the unprecedented progress of biomedical nanotechnology in the past few decades, traditional drug delivery systems (DDSs) have been incorporated into intelligent DDSs with stimulus responsive characteristics. Graphene oxide (GO) and Chitosan (CS) have excellent physical, chemical, mechanical, and optical properties, and their synergistic effects have attracted widespread attention in the biomedical field. In this review, we focus on the physicochemical characteristics of GO, CS, and GO/CS composites, as well as the research progress of DDS types based on GO/CS. Full article

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

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21 pages, 8014 KiB

Open AccessArticle

Independent Acidic pH Reactivity of Non-Iron-Fenton Reaction Catalyzed by Copper-Based Nanoparticles for Fluorescent Dye Oxidation

by Zakia H. Alhashem, Hasna Abdullah Alali, Shehab A. Mansour, Maha A. Tony and Ashraf H. Farha

Inorganics 2025, 13(3), 97; https://doi.org/10.3390/inorganics13030097 - 20 Mar 2025

Abstract

The process of hydrogen peroxide decomposition, facilitated by copper oxide nanoparticles, produces reactive oxidants that possess the ability to oxidize multiple pollutants. CuO/Cu₂O hybrid nanoparticles were successfully synthesized through a thermal decomposition route and applied as a heterogeneous catalytic oxidant for [...] Read more.

The process of hydrogen peroxide decomposition, facilitated by copper oxide nanoparticles, produces reactive oxidants that possess the ability to oxidize multiple pollutants. CuO/Cu₂O hybrid nanoparticles were successfully synthesized through a thermal decomposition route and applied as a heterogeneous catalytic oxidant for a fluorescent dye, namely Basic Violet 10 (BV10) dye. The microstructure and morphology of the prepared catalyst were evaluated via X-ray diffraction (XRD) and a field-emission scanning electron microscope (FE-SEM), respectively. The produced nanoparticles (NPs) were induced through ultraviolet light as a green photodecomposition technology. The system parameters were investigated, and the optimal initial NP concentration, H₂O₂ concentration, and pH were assessed. The highest removal rate corresponding to 82% was achieved when 40 and 400 mg/L of NPs and H₂O₂ were introduced, respectively. The system could operate at various pH values, and the alkaline pH (8.0) was efficient in proceeding with the oxidation system that overcomes the limitation of the homogeneous acidic Fenton catalyst. The introduced catalyst demonstrated consistent sustainability, achieving a notable removal rate of 68% even after six consecutive cycles of use. This innovative technique’s accomplishment examines the feasibility of utilizing copper as a replacement for iron in the Fenton reaction, demonstrating efficacy over an extended pH range. Finally, the temperature effectiveness of the reaction showed that the reaction is exothermic in nature, working at a low energy barrier (20.4 kJ/mol) and following the pseudo-second-order kinetic model. Full article

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