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15 pages, 2469 KiB  
Review
Recent Developments of Nanomaterials in Crop Growth and Production: The Case of the Tomato (Solanum lycopersicum)
by Eric G. Echeverría-Pérez, Vianii Cruz-López, Rosario Herrera-Rivera, Mario J. Romellón-Cerino, Jesusita Rosas-Diaz and Heriberto Cruz-Martínez
Agronomy 2025, 15(7), 1716; https://doi.org/10.3390/agronomy15071716 - 16 Jul 2025
Viewed by 514
Abstract
Tomatoes are a fundamental part of the daily diet, rich in carbohydrates, vitamins, minerals, carotenoids, and polyphenols. Nonetheless, optimal fruit yield and quality typically depend on the application of synthetic agrochemicals. However, the irrational use of these agrochemicals has caused various environmental problems. [...] Read more.
Tomatoes are a fundamental part of the daily diet, rich in carbohydrates, vitamins, minerals, carotenoids, and polyphenols. Nonetheless, optimal fruit yield and quality typically depend on the application of synthetic agrochemicals. However, the irrational use of these agrochemicals has caused various environmental problems. Therefore, it is necessary to develop alternatives to conventional agrochemical products. Applying nanomaterials as fertilizers in tomato production is emerging as a promising approach, with documented improvements in germination, vegetative development, and fruit yield. Therefore, we present a comprehensive review of recent developments (2015–2024) in the application of nanomaterials in tomato crops, with a particular emphasis on the significance of nanomaterial characteristics in their role as fertilizers. Several types of nanomaterials, such as ZnO, Ag, TiO2, Si, hydroxyapatite, P, Zn, Se, CuO, Cu, Fe, Fe2O3, CaO, CaCO3, and S, have been evaluated as fertilizers for tomato crops, with ZnO nanoparticles being the most extensively studied. However, it is pertinent to conduct further research on the less-explored nanomaterials to gain a deeper understanding of their effects on seed germination, plant growth, and fruit quality and quantity. Full article
(This article belongs to the Special Issue Application of Nanotechnology in Agricultural Food Engineering)
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19 pages, 5775 KiB  
Article
Optimizing Zinc Selenide and Silicon-Based Heterojunction Solar Cells for Enhanced Photovoltaic Performance
by Amina Laouid, Amine Alaoui Belghiti, Ali Abouais, Krzysztof Wisniewski, Mouhaydine Tlemçani, Przemysław Płóciennik, Abdelowahed Hajjaji and Anna Zawadzka
Solar 2025, 5(3), 29; https://doi.org/10.3390/solar5030029 - 25 Jun 2025
Viewed by 335
Abstract
In the purpose of enhancing solar cell efficiency and sustainability, zinc selenide (ZnSe) and silicon (Si) play indispensable roles, offering a compelling combination of stability and transparency while also highlighting their abundant availability. This study utilizes the SCAPS_1D tool to explore diverse heterojunction [...] Read more.
In the purpose of enhancing solar cell efficiency and sustainability, zinc selenide (ZnSe) and silicon (Si) play indispensable roles, offering a compelling combination of stability and transparency while also highlighting their abundant availability. This study utilizes the SCAPS_1D tool to explore diverse heterojunction setups, aiming to solve the nuanced correlation between key parameters and photovoltaic performance, therefore contributing significantly to the advancement of sustainable energy solutions. Exploring the performance analysis of heterojunction solar cell configurations employing ZnSe and Si elements, various configurations including SnO2/ZnSe/p_Si/p+_Si, SnO2/CdS/p_Si/p+_Si, TiO2/ZnSe/p_Si/p+_Si, and TiO2/CdS/p_Si/p+_Si are investigated, delving into parameters such as back surface field thickness (BSF), doping concentration, operating temperature, absorber layer properties, electron transport layer properties, interface defects, series and shunt resistance. Among these configurations, the SnO2/ZnSe/p_Si/p+_Si configuration with a doping concentration of 1019 cm−3 and a BSF thickness of 2 μm, illustrates a remarkable conversion efficiency of 22.82%, a short circuit current density (Jsc) of 40.33 mA/cm2, an open circuit voltage (Voc) of 0.73 V, and a fill factor (FF) of 77.05%. Its environmentally friendly attributes position it as a promising contender for advanced photovoltaic applications. This work emphasizes the critical role of parameter optimization in propelling solar cell technologies toward heightened efficiency and sustainability. Full article
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18 pages, 1812 KiB  
Review
Cadmium-Free Buffer Layer Materials for Kesterite Thin-Film Solar Cells: An Overview
by Nafees Ahmad and Guangbao Wu
Energies 2025, 18(12), 3198; https://doi.org/10.3390/en18123198 - 18 Jun 2025
Cited by 1 | Viewed by 536
Abstract
Kesterite (CZTS/CZTSSe) thin-film solar cells are considered an eco-friendly, earth-abundant, and low-cost photovoltaic technology that can fulfill our future energy needs. Due to its outstanding properties including tunable bandgap and high absorption coefficient, the power conversion efficiency (PCE) has reached over 14%. However, [...] Read more.
Kesterite (CZTS/CZTSSe) thin-film solar cells are considered an eco-friendly, earth-abundant, and low-cost photovoltaic technology that can fulfill our future energy needs. Due to its outstanding properties including tunable bandgap and high absorption coefficient, the power conversion efficiency (PCE) has reached over 14%. However, toxic cadmium sulfide (CdS) is commonly used as an n-type buffer layer in kesterite thin-film solar cells (KTFSCs) to form a better p–n junction with the p-type CZTS/CZTSSe absorber. In addition to its toxicity, the CdS buffer layer shows parasitic absorption at low wavelengths (400–500 nm) owing to its low bandgap (2.4 eV). For the last few years, several efforts have been made to substitute CdS with an eco-friendly, Cd-free, cost-effective buffer layer with alternative large-bandgap materials such as ZnSnO, Zn (O, S), In2Se3, ZnS, ZnMgO, and TiO2, which showed significant advances. Herein, we summarize the key findings of the research community using a Cd-free buffer layer in KTFSCs to provide a current scenario for future work motivating researchers to design new materials and strategies to achieve higher performance. Full article
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15 pages, 4545 KiB  
Article
CNT:TiO2-Doped Spiro-MeOTAD/Selenium Foam Heterojunction for High-Stability Self-Powered Broadband Photodetector
by Yuxin Huang, Pengfan Li, Xuewei Yu, Shiliang Feng, Yanfeng Jiang and Pingping Yu
Nanomaterials 2025, 15(12), 916; https://doi.org/10.3390/nano15120916 - 12 Jun 2025
Viewed by 418
Abstract
Photodetectors are critical components in modern optoelectronic systems due to their extensive applications in information conversion and image storage. Selenium (Se), an element with a low melting point, a broad spectral response, and rapid response speed, exhibits a disadvantage of high optical reflectivity, [...] Read more.
Photodetectors are critical components in modern optoelectronic systems due to their extensive applications in information conversion and image storage. Selenium (Se), an element with a low melting point, a broad spectral response, and rapid response speed, exhibits a disadvantage of high optical reflectivity, which leads to a reduction in response. Spiro-MeOTAD, featuring controllable energy bands and facile processing, has its practical application limited by inadequate thermal and environmental stability. In this study, Spiro-MeOTAD-1 with enhanced stability was prepared through the optimization of dopants (Zn(TFSI)2 and CNT:TiO2) within Spiro-MeOTAD, to create a Se-F/Spiro-MeOTAD-1 heterojunction photodetector by subsequently compositing with selenium foam (Se-F). The self-powered device demonstrates exceptional photovoltaic performance within the wavelength range of 350–800 nm at 0 V bias, exhibiting a maximum responsivity of 108 mA W−1, a switching ratio of 5 × 103, a specific detectivity of 2.96 × 1012 Jones, and a response time of 20 ms/50 ms. The device also demonstrates elevated environmental stability pretreatment at 140 °C following a one-month period. The photodetection stability of the Se-F/Spiro-MeOTAD-1 flexible PD was demonstrated by its capacity to retain 76.3% of its initial light current when subjected to 70 bending cycles at 30°. This finding further substantiates the photodetection stability of the material under various bending conditions. Further verification of the applicability of Spiro-MeOTAD-1 in Se-based devices establishes a novel paradigm for designing photodetectors with enhanced performance and stability. Full article
(This article belongs to the Special Issue Optoelectronic Functional Nanomaterials and Devices)
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24 pages, 70177 KiB  
Article
Geology, Structure, Geochemistry, and Origin of Iron Oxide Deposits in Dehbid, Southwest Iran
by Abdorrahman Rajabi, Reza Nozaem, Sara Momenipour, Shojaedin Niroomand, Shahrokh Rajabpour, Somaye Rezaei, Pura Alfonso, Carles Canet, Ahmad Kazemi Mehrnia, Pouria Mahmoodi, Amir Mahdavi, Mansoor Kazemirad, Omid Laghari Firouzjaei and Mohammad Amini
Minerals 2025, 15(6), 590; https://doi.org/10.3390/min15060590 - 30 May 2025
Viewed by 921
Abstract
The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a [...] Read more.
The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a NW–SE oriented ductile shear zone, parallel to the Zagros thrust zone, experienced significant deformation. Detailed structural studies indicate that the iron mineralization is primarily stratiform to stratabound and hosted in late Triassic to early Jurassic silicified dolomites and schists. These ore deposits consist of lenticular iron oxide orebodies and exhibit various structures and textures, including banded, laminated, folded, disseminated, and massive forms of magnetite and hematite. The Fe2O3 content in the mineralized layers varies from 30 to 91 wt%, whereas MnO has an average of 3.9 wt%. The trace elements are generally low, except for elevated concentrations of Cu (up to 4350 ppm) and Zn (up to 3270 ppm). Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis of magnetite reveals high concentrations of Mg, Al, Si, Mn, Ti, Cu, and Zn, with significant depletion of elements such as Ga, Ge, As, and Nb. This study refutes the hypothesis of vein-like or hydrothermal genesis, providing evidence for a sedimentary origin based on the trace element geochemistry of magnetite and LA-ICP-MS geochemical data. The Dehbid banded iron ores (BIOs) are thought to have formed under geodynamic conditions similar to those of BIOs in back-arc tectonic settings. The combination of anoxic conditions, submarine hydrothermal iron fluxes, and redox fluctuations is essential for the formation of these deposits, suggesting that similar iron–manganese deposits can form during the Phanerozoic under specific geodynamic and oceanographic conditions, particularly in tectonically active back-arc environments. Full article
(This article belongs to the Special Issue Mineralogy and Geochemistry of Polymetallic Ore Deposits)
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28 pages, 6012 KiB  
Review
Semiconductor-Based Photoelectrocatalysts in Water Splitting: From the Basics to Mechanistic Insights—A Brief Review
by W. J. Pech-Rodríguez, Nihat Ege Şahin, G. G. Suarez-Velázquez and P. C. Meléndez-González
Materials 2025, 18(9), 1952; https://doi.org/10.3390/ma18091952 - 25 Apr 2025
Cited by 1 | Viewed by 1128
Abstract
Hydrogen and oxygen serve as energy carriers that can ease the transition of energy due to their high energy densities. Nonetheless, their production processes entail the development of efficient and low-cost storage and conversion technologies. In this regard, photoelectrocatalysts are materials based on [...] Read more.
Hydrogen and oxygen serve as energy carriers that can ease the transition of energy due to their high energy densities. Nonetheless, their production processes entail the development of efficient and low-cost storage and conversion technologies. In this regard, photoelectrocatalysts are materials based on the photoelectronic effect where electrons and holes interact with H2O, producing H2 and O2, and in some cases, this is achieved with acceptable efficiency. Although there are several reviews on this topic, most of them focus on traditional semiconductors, such as TiO2 and ZnO, neglecting others, such as those based on non-noble metals and organic ones. Herein, semiconductors like CdSe, NiWO4, Fe2O3, and others have been investigated and compared in terms of photocurrent density, band gap, and charge transfer resistance. In addition, this brief review aims to discuss the mechanisms of overall water-splitting reactions from a photonic point of view and subsequently discusses the engineering of material synthesis. Advanced composites are also addressed, such as WO3/BiVO4/Cu2O and CN-FeNiOOH-CoOOH, which demonstrate high efficiency by delivering photocurrent densities of 5 mAcm−2 and 3.5 mA cm−2 at 1.23 vs. RHE, respectively. Finally, the authors offer their perspectives and list the main challenges based on their experience in developing semiconductor-based materials applied in several fields. In this manner, this brief review provides the main advances in these topics, used as references for new directions in designing active materials for photoelectrocatalytic water splitting. Full article
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13 pages, 10147 KiB  
Article
Effect of Quantum Dot-Based Remote Lenses on the Emission Properties of White LED Lighting Studied by Optical Simulation and Experiment
by Sung Min Park, Eunki Baek, Sohee Kim, Jaehyeong Yoo, Sung-Yoon Joe, Jae-Hyeon Ko, Taehee Park and Young Wook Ko
Ceramics 2025, 8(2), 39; https://doi.org/10.3390/ceramics8020039 - 19 Apr 2025
Viewed by 633
Abstract
The introduction of side-emitting lenses into white light-emitting diodes (LEDs) has enabled thin panel lighting technology based on LED technology, but also presents the disadvantage of low color rendering due to insufficient red components in the spectra of typical white LEDs. Additional application [...] Read more.
The introduction of side-emitting lenses into white light-emitting diodes (LEDs) has enabled thin panel lighting technology based on LED technology, but also presents the disadvantage of low color rendering due to insufficient red components in the spectra of typical white LEDs. Additional application of remote quantum dot (QD) components such as QD films or caps presents the issues of increased numbers of components and higher costs. In this study, we incorporated red QDs directly into a lens placed on white LEDs and analyzed the effects of QD lenses on the optical characteristics of a lighting device through experiments and simulations. By incorporating red CdSe/ZnS QDs into UV-curable resin to fabricate QD lenses and applying them to white LEDs, we significantly improved the color rendering index and were able to adjust the correlated color temperature over a wide range between 2700 and 9900 K. However, as the concentration of QDs in the lens increased, scattering by the QD particles was enhanced, strengthening the Lambertian distribution in the intensity plot. Following the development of optical models for QD lenses under experimental conditions, comprehensive optical simulations of white LED lighting systems revealed that increasing the device height proved more effective than modifying TiO2 scattering particle concentration in the diffuser plate for mitigating QD-induced bright spots and enhancing illumination uniformity. Full article
(This article belongs to the Special Issue Advances in Ceramics, 3rd Edition)
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21 pages, 3744 KiB  
Article
Modeling and Analysis of KSnI3 Perovskite Solar Cells Yielding Power Conversion Efficiency of 30.21%
by Bonginkosi Vincent Kheswa, Siyabonga Ntokozo Thandoluhle Majola, Hmoud Al-Dmour, Nolufefe Muriel Ndzane and Lucky Makhathini
Nanomaterials 2025, 15(8), 580; https://doi.org/10.3390/nano15080580 - 11 Apr 2025
Cited by 2 | Viewed by 662
Abstract
KSnI3-based perovskite solar cells have attracted a lot of research interest due their unique electronic, optical, and thermal properties. In this study, we optimized the performance of various lead-free perovskite solar cell structures—specifically, FTO/Al–ZnO/KSnI3/rGO/Se, FTO/LiTiO2/KSnI3/rGO/Se, [...] Read more.
KSnI3-based perovskite solar cells have attracted a lot of research interest due their unique electronic, optical, and thermal properties. In this study, we optimized the performance of various lead-free perovskite solar cell structures—specifically, FTO/Al–ZnO/KSnI3/rGO/Se, FTO/LiTiO2/KSnI3/rGO/Se, FTO/ZnO/KSnI3/rGO/Se, and FTO/SnO2/KSnI3/rGO/Se, using the SCAPS-1D simulation tool. The optimization focused on the thicknesses and dopant densities of the rGO, KSnI3, Al–ZnO, LiTiO2, ZnO, and SnO2 layers, the thickness of the FTO electrode, as well as the defect density of KSnI3. This yielded PCE values of 27.60%, 24.94%, 27.62%, and 30.21% for the FTO/Al–ZnO/KSnI3/rGO/Se, FTO/LiTiO2/KSnI3/rGO/Se, FTO/ZnO/KSnI3/rGO/Se, and FTO/SnO2/KSnI3/rGO/Se perovskite solar cell configurations, respectively. The FTO/SnO2/KSnI3/rGO/Se device is 7.43% more efficient than the FTO/SnO2/3C-SiC/KSnI3/NiO/C device, which is currently the highest performing KSnI3-based perovskite solar cell in the literature. Thus, our FTO/SnO2/KSnI3/rGO/Se perovskite solar cell structure is now, by far, the most efficient PSC design. Its best performance is achieved under ideal conditions of a series resistance of 0.5 Ω cm2, a shunt resistance of 107 Ω cm2, and a temperature of 371 K. Full article
(This article belongs to the Section Solar Energy and Solar Cells)
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12 pages, 1742 KiB  
Article
Simulation of Lead-Free Perovskite Solar Cells with Improved Performance
by Saood Ali, Praveen Kumar, Khursheed Ahmad and Rais Ahmad Khan
Crystals 2025, 15(2), 171; https://doi.org/10.3390/cryst15020171 - 10 Feb 2025
Cited by 5 | Viewed by 1104
Abstract
At present, lead halide PVSKSCs are promising photovoltaic cells but have some limitations, including their low stability in ambient conditions and the toxicity of lead. Thus, it will be of great significance to explore lead-free perovskite materials as an alternative absorber layer. In [...] Read more.
At present, lead halide PVSKSCs are promising photovoltaic cells but have some limitations, including their low stability in ambient conditions and the toxicity of lead. Thus, it will be of great significance to explore lead-free perovskite materials as an alternative absorber layer. In recent years, the numerical simulation of perovskite solar cells (PVSKSCs) via the solar cell capacitance simulation (SCAPS) method has attracted the attention of the scientific community. In this work, we adopted SCAPS for the theoretical study of lead (Pb)-free PVSKSCs. A cesium bismuth iodide (CsBi3I10; CBI) perovskite-like material was used as an absorber layer. The thickness of the CBI layer was optimized. In addition, different electron transport layers (ETLs), such as titanium dioxide (TiO2), tin oxide (SnO2), zinc oxide (ZnO), and zinc selenide (ZnSe), and different hole transport layers, such as spiro-OMeTAD (2,2,7,7-tetrakis(N,N-di(4-methoxyphenylamine)-9,9′-spirobifluorene), poly(3-hexylthiophene-2,5-diyl) (P3HT), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), and copper oxide (Cu2O), were explored for the simulation of CBI-based PVSKSCs. A device structure of FTO/ETL/CBI/HTL/Au was adopted for simulation studies. The simulation studies showed the improved photovoltaic performance of CBI-based PVSKSCs using spiro-OMeTAD and TiO2 as the HTL and ETL, respectively. An acceptable PCE of 11.98% with a photocurrent density (Jsc) of 17.360258 mA/cm2, a fill factor (FF) of 67.10%, and an open-circuit voltage (Voc) of 1.0282 V were achieved under the optimized conditions. It is expected that the present study will be beneficial for researchers working towards the development of CBI-based PVSKSCs. Full article
(This article belongs to the Section Materials for Energy Applications)
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24 pages, 3518 KiB  
Article
A Numerical Simulation Study of the Impact of Kesterites Hole Transport Materials in Quantum Dot-Sensitized Solar Cells Using SCAPS-1D
by Sindisiwe Jakalase, Azile Nqombolo, Edson L. Meyer, Mojeed A. Agoro and Nicholas Rono
Nanomaterials 2024, 14(24), 2016; https://doi.org/10.3390/nano14242016 - 15 Dec 2024
Cited by 3 | Viewed by 1633
Abstract
Energy generation and storage are critical challenges for developing economies due to rising populations and limited access to clean energy resources. Fossil fuels, commonly used for energy production, are costly and contribute to environmental pollution through greenhouse gas emissions. Quantum dot-sensitized solar cells [...] Read more.
Energy generation and storage are critical challenges for developing economies due to rising populations and limited access to clean energy resources. Fossil fuels, commonly used for energy production, are costly and contribute to environmental pollution through greenhouse gas emissions. Quantum dot-sensitized solar cells (QDSSCs) offer a promising alternative due to their stability, low cost, and high-power conversion efficiency (PCE) compared to other third-generation solar cells. Kesterite materials, known for their excellent optoelectronic properties and chemical stability, have gained attention for their potential as hole transport layer (HTL) materials in solar cells. In this study, the SCAPS-1D numerical simulator was used to analyze a solar cell with the configuration FTO/TiO2/MoS2/HTL/Ag. The electron transport layer (ETL) used was titanium dioxide (TiO2), while Cu2FeSnS4 (CFTS), Cu2ZnSnS4 (CZTSe), Cu2NiSnS4 (CNTS), and Cu2ZnSnSe4 (CZTSSe) kesterite materials were evaluated as HTLs. MoS2 quantum dot served as the absorber, with FTO as the anode and silver as the back metal contact. The CFTS material outperformed the others, yielding a PCE of 25.86%, a fill factor (FF) of 38.79%, a short-circuit current density (JSC) of 34.52 mA cm−2, and an open-circuit voltage (VOC) of 1.93 V. This study contributes to the advancement of high-performance QDSSCs. Full article
(This article belongs to the Section Solar Energy and Solar Cells)
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11 pages, 4655 KiB  
Article
Compositional Optimization of Sputtered SnO2/ZnO Films for High Coloration Efficiency
by Zoltán Lábadi, Noor Taha Ismaeel, Péter Petrik and Miklós Fried
Int. J. Mol. Sci. 2024, 25(19), 10801; https://doi.org/10.3390/ijms251910801 - 8 Oct 2024
Cited by 1 | Viewed by 1085
Abstract
We performed an electrochromic investigation to optimize the composition of reactive magnetron-sputtered mixed layers of zinc oxide and tin oxide (ZnO-SnO2). Deposition experiments were conducted as a combinatorial material synthesis approach. The binary system for the samples of SnO2-ZnO [...] Read more.
We performed an electrochromic investigation to optimize the composition of reactive magnetron-sputtered mixed layers of zinc oxide and tin oxide (ZnO-SnO2). Deposition experiments were conducted as a combinatorial material synthesis approach. The binary system for the samples of SnO2-ZnO represented the full composition range. The coloration efficiency (CE) was determined for the mixed oxide films with the simultaneous measurement of layer transmittance, in a conventional three-electrode configuration, and an electric current was applied by using organic propylene carbonate electrolyte cells. The optical parameters and composition were measured and mapped by using spectroscopic ellipsometry (SE). Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) measurements were carried out to check the SE results, for (TiO2-SnO2). Pure metal targets were placed separately from each other, and the indium–tin-oxide (ITO)-covered glass samples and Si-probes on a glass holder were moved under the two separated targets (Zn and Sn) in a reactive argon–oxygen (Ar-O2) gas mixture. This combinatorial process ensured that all the compositions (from 0 to 100%) were achieved in the same sputtering chamber after one sputtering preparation cycle. The CE data evaluated from the electro-optical measurements plotted against the composition displayed a characteristic maximum at around 29% ZnO. The accuracy of our combinatorial approach was 5%. Full article
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33 pages, 6968 KiB  
Article
Mineralogy and Geochemistry of Jasperoid Veins in Neoproterozoic Metavolcanics: Evidence of Silicification, Pyritization and Hematization
by Mohamed Zaki Khedr, Mahmoud A. Sayed, Shehata Ali, Mokhles K. Azer, Yuji Ichiyama, Eiichi Takazawa, Ali Y. Kahal, Kamal Abdelrahman and Ali M. Mahdi
Minerals 2024, 14(7), 647; https://doi.org/10.3390/min14070647 - 25 Jun 2024
Cited by 1 | Viewed by 1972
Abstract
The Wadi Ranga sulfidic jasperoids in the Southern Eastern Desert (SED) of Egypt are hosted within the Neoproterozoic Shadli metavolcanics as an important juvenile crustal section of the Arabian Nubian Shield (ANS). This study deals with remote sensing and geochemical data to understand [...] Read more.
The Wadi Ranga sulfidic jasperoids in the Southern Eastern Desert (SED) of Egypt are hosted within the Neoproterozoic Shadli metavolcanics as an important juvenile crustal section of the Arabian Nubian Shield (ANS). This study deals with remote sensing and geochemical data to understand the mechanism and source of pyritization, silicification, and hematization in the host metavolcanics and to shed light on the genesis of their jasperoids. The host rocks are mainly dacitic to rhyolitic metatuffs, which are proximal to volcanic vents. They show peraluminous calc-alkaline affinity. These felsic metatuffs also exhibit a nearly flat REE pattern with slight LREE enrichment (La/Yb = 1.19–1.25) that has a nearly negative Eu anomaly (Eu/Eu* = 0.708–0.776), while their spider patterns display enrichment in Ba, K, and Pb and depletion in Nb, Ta, P, and Ti, reflecting the role of slab-derived fluid metasomatism during their formation in the island arc setting. The ratios of La/Yb (1.19–1.25) and La/Gd (1.0–1.17) of the studied felsic metatuffs are similar to those of the primitive mantle, suggesting their generation from fractionated melts that were derived from a depleted mantle source. Their Nb and Ti negative anomalies, along with the positive anomalies at Pb, K, Rb, and Ba, are attributed to the influence of fluids/melt derived from the subducted slab. The Wadi Ranga jasperoids are mainly composed of SiO2 (89.73–90.35 wt.%) and show wide ranges of Fe2O3t (2.73–6.63 wt.%) attributed to the significant amount of pyrite (up to 10 vol.%), hematite, goethite, and magnetite. They are also rich in some base metals (Cu + Pb + Zn = 58.32–240.68 ppm), leading to sulfidic jasperoids. Pyrite crystals with a minor concentration of Ag (up to 0.32 wt.%) are partially to completely converted to secondary hematite and goethite, giving the red ochre and forming hematization. Euhedral cubic pyrite is of magmatic origin and was formed in the early stages and accumulated in jasperoid by epigenetic Si-rich magmatic-derived hydrothermal fluids; pyritization is considered a magmatic–hydrothermal stage, followed by silicification and then hematization as post-magmatic stages. The euhedral apatite crystals in jasperoid are used to estimate the saturation temperature of their crystallization from the melt at about 850 °C. The chondrite (C1)-normalized REE pattern of the jasperoids shows slightly U–shaped patterns with a slightly negative Eu anomaly (Eu/Eu* = 0.43–0.98) due to slab-derived fluid metasomatism during their origin; these jasperoids are also rich in LILEs (e.g., K, Pb, and Sr) and depleted in HFSEs (e.g., Nb and Ta), reflecting their hydrothermal origin in the island arc tectonic setting. The source of silica in the studied jasperoids is likely derived from the felsic dyke and a nearby volcanic vent, where the resultant Si-rich fluids may circulate along the NW–SE, NE–SW, and E–W major faults and shear zones in the surrounding metavolcanics to leach Fe, S, and Si to form hydrothermal jasperoid lenses and veins. Full article
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14 pages, 3739 KiB  
Article
Exploring the Potential of Nitrogen-Doped Graphene in ZnSe-TiO2 Composite Materials for Supercapacitor Electrode
by Hassan Akbar, Asghar Ali, Shoaib Mohammad, Faiza Anjum, Ashfaq Ahmad, Amir Muhammad Afzal, Munirah D. Albaqami, Saikh Mohammad and Jeong Ryeol Choi
Molecules 2024, 29(9), 2103; https://doi.org/10.3390/molecules29092103 - 2 May 2024
Cited by 3 | Viewed by 1873
Abstract
The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic [...] Read more.
The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) are evaluated for the supercapacitor electrode material. Results demonstrate improved performance in the ZnSe-NG-TiO2 composite, indicating its potential for advanced supercapacitors with enhanced efficiency, stability, and power density. Specific capacity calculations and galvanic charge-discharge experiments confirmed the promising electrochemical activity of ZnSe-NG-TiO2, which has a specific capacity of 222 C/g. The negative link among specific capacity and current density demonstrated the composite’s potential for high energy density and high-power density electrochemical devices. Overall, the study shows that composite materials derived from multiple families can synergistically improve electrode characteristics for advanced energy storage applications. Full article
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30 pages, 6637 KiB  
Review
Enrichment Characteristics and Mechanisms of Critical Metals in Marine Fe-Mn Crusts and Nodules: A Review
by Sucheng Huang and Yazhou Fu
Minerals 2023, 13(12), 1532; https://doi.org/10.3390/min13121532 - 9 Dec 2023
Cited by 11 | Viewed by 3546
Abstract
Marine Co-rich ferromanganese crusts and polymetallic nodules, which are widely distributed in oceanic environments, are salient potential mineral resources that are enriched with many critical metals. Many investigations have achieved essential progress and findings regarding critical metal enrichment in Fe-Mn crusts and nodules. [...] Read more.
Marine Co-rich ferromanganese crusts and polymetallic nodules, which are widely distributed in oceanic environments, are salient potential mineral resources that are enriched with many critical metals. Many investigations have achieved essential progress and findings regarding critical metal enrichment in Fe-Mn crusts and nodules. This study systematically reviews the research findings of previous investigations and elaborates in detail on the enrichment characteristics, enrichment processes and mechanisms and the influencing factors of the critical metals enriched in Fe-Mn crusts and nodules. The influencing factors of critical metal enrichments in Fe-Mn crusts and nodules mainly include the growth rate, water depth, post-depositional phosphatization and structural uptake of adsorbents. The major enrichment pathways of critical metals in marine Fe-Mn (oxy)hydroxides are primarily as follows: direct substitution on the surface of δ-MnO2 for Ni, Cu, Zn and Li; oxidative substitution on the δ-MnO2 surface for Co, Ce and Tl; partition between Mn and Fe phases through surface complexation according to electro-species attractiveness for REY (except for Ce), Cd, Mo, W and V; combined Mn-Fe phases enrichment for seawater anionic Te, Pt, As and Sb, whose low-valence species are mostly oxidatively enriched on δ-MnO2, in addition to electro-chemical adsorption onto FeOOH, while high-valence species are likely structurally incorporated by amorphous FeOOH; and dominant sorption and incorporation by amorphous FeOOH for Ti and Se. The coordination preferences of critical metals in the layered and tunneled Mn oxides are primarily as follows: metal incorporations in the layer/tunnel-wall for Co, Ni and Cu; triple-corner-sharing configurations above the structural vacancy for Co, Ni, Cu, Zn and Tl; double-corner-sharing configurations for As, Sb, Mo, W, V and Te; edge-sharing configurations at the layer rims for corner-sharing metals when they are less competitive in taking up the corner-sharing position or under less oxidizing conditions when the metals are less feasible for reactions with layer vacancy; and hydrated interlayer or tunnel-center sorption for Ni, Cu, Zn, Cd, Tl and Li. The major ore-forming elements (e.g., Co, Ni, Cu and Zn), rare earth elements and yttrium, platinum-group elements, dispersed elements (e.g., Te, Tl, Se and Cd) and other enriched critical metals (e.g., Li, Ti and Mo) in polymetallic nodules and Co-rich Fe-Mn crusts of different geneses have unique and varied enrichment characteristics, metal occurrence states, enrichment processes and enrichment mechanisms. This review helps to deepen the understanding of the geochemical behaviors of critical metals in oceanic environments, and it also bears significance for understanding the extreme enrichment and mineralization of deep-sea critical metals. Full article
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25 pages, 6134 KiB  
Article
Geochemical and Isotopic Fractionation in the Hypogene Ore, Gossan, and Saprolite of the Alvo 118 Deposit: Implications for Copper Exploration in the Regolith of the Carajás Mineral Province
by Pabllo Henrique Costa dos Santos, Marcondes Lima da Costa and Desiree Lisette Roerdink
Minerals 2023, 13(11), 1441; https://doi.org/10.3390/min13111441 - 15 Nov 2023
Cited by 2 | Viewed by 1944
Abstract
In the Carajás Mineral Province, gossan formation and lateritization have produced numerous supergene orebodies at the expense of IOCG deposits and host rocks. The Alvo 118 deposit comprises massive and disseminated hypogene copper sulfides associated with gossan and mineralized saprolites. The hypogene reserves [...] Read more.
In the Carajás Mineral Province, gossan formation and lateritization have produced numerous supergene orebodies at the expense of IOCG deposits and host rocks. The Alvo 118 deposit comprises massive and disseminated hypogene copper sulfides associated with gossan and mineralized saprolites. The hypogene reserves are 170 Mt, with 1% Cu and 0.3 ppm Au, while the supergenes are 55 Mt, comprised of 30% gossan and 70% saprolite, with 0.92% Cu and 0.03 ppm Au. The gossan includes goethite, malachite, cuprite, and libethenite zones. The saprolite comprises kaolinite, vermiculite, smectite, and relics of chlorite. In the hypogene mineralization, Ag, Te, Pb, Se, Bi, Au, In, Y, Sn, and U are mainly hosted by chalcopyrite and petzite, altaite, galena, uraninite, stannite, and cassiterite. In the gossan, Ag, Te, Pb, Se, and Bi are hosted by Cu minerals, while Au, In, Y, Sn, and U are associated with iron oxyhydroxides, in addition to Zn, As, Be, Ga, Ga, Mo, Ni, and Sc. As supporting information, δ65Cu values indicate that the gossan is immature and, at least partly, not affected by leaching. In the saprolite, Ga, Sc, Sn, V, Mn, Co, and Cr are associated with the iron oxyhydroxides, partially derived from the host rock weathering. The δ56Fe values indicate that hypogene low contribution of the hypogene mineralization to the saprolite iron content. The association of Al2O3, Hf, Zr, Th, TiO2, Ce, La, Ba, and Sr represents the geochemical signature of the host rocks, with dominant contributions from chlorites, while In, Y, Te, Pb, Bi, and Se are the main pathfinders of Cu mineralization. Full article
(This article belongs to the Special Issue Mineral Evolution and Mineralization during Weathering)
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