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21 pages, 7441 KiB  
Article
Nanoparticle-Reinforced Electroless Composite Coatings for Pipeline Steel: Synthesis and Characterization
by Biplab Baran Mandal, Vikash Kumar, Sovan Sahoo, Buddhadeb Oraon and Sumanta Mukherjee
Materials 2025, 18(17), 3949; https://doi.org/10.3390/ma18173949 - 22 Aug 2025
Abstract
Protective coatings are essential for extending the service life of components exposed to harsh conditions, such as pipes used in industrial systems, where wear and corrosion remain constant challenges. This study explores the development of a nano-sized TiO2-reinforced electroless nickel-based ternary [...] Read more.
Protective coatings are essential for extending the service life of components exposed to harsh conditions, such as pipes used in industrial systems, where wear and corrosion remain constant challenges. This study explores the development of a nano-sized TiO2-reinforced electroless nickel-based ternary (Ni-W-P) alloy and composite coating on API X60 steel, a high-strength carbon steel pipe grade widely used in oil and gas pipelines, using an alkaline hypophosphite-reduced bath. The surface morphology, microstructure, elemental composition, structure, phase evolution, adhesion, and roughness of the coatings were analyzed using optical microscopy, FESEM, EDS, XRD, AFM, cross-cut tape test, and 3D profilometry. The tribological performance was evaluated via Vickers microhardness measurements and reciprocating wear tests conducted under dry conditions at a 5 N load. The TiO2 nanoparticle-reinforced composite coating achieved a consistent thickness of approximately 24 µm and exhibited enhanced microhardness and reduced coefficient of friction (COF), although the addition of nanoparticles increased surface roughness (Sa). Annealing the electroless composites at 400 °C led to a significant improvement in their tribological properties, primarily owing to the grain growth, phase transformation, and Ni3P crystallization. XRD analysis revealed phase evolution from an amorphous state to crystalline Ni3P upon annealing. Both the alloy and composite coatings exhibited excellent adhesion performances. The combined effect of TiO2 nanoparticles, tungsten, and Ni3P crystallization greatly improved the wear resistance, with abrasive and adhesive wear identified as the dominant mechanisms, making these coatings well suited for high-wear applications. Full article
(This article belongs to the Section Advanced Nanomaterials and Nanotechnology)
29 pages, 5199 KiB  
Review
Recent Progress on Synthesis and Electrochemical Performance of Iron Fluoride Conversion Cathodes for Li-Ion Batteries
by Jiabin Tian, Ziyi Yang, Yayun Zheng and Zhengfei Chen
Solids 2025, 6(3), 47; https://doi.org/10.3390/solids6030047 - 22 Aug 2025
Abstract
Despite notable advancements in lithium-ion battery (LIB) technology, growing industrialization, rising energy demands, and evolving consumer electronics continue to raise performance requirements. As the primary determinant of battery performance, cathode materials have become a central research focus. Among emerging candidates, iron-based fluorides show [...] Read more.
Despite notable advancements in lithium-ion battery (LIB) technology, growing industrialization, rising energy demands, and evolving consumer electronics continue to raise performance requirements. As the primary determinant of battery performance, cathode materials have become a central research focus. Among emerging candidates, iron-based fluorides show great promise due to their high theoretical specific capacities, elevated operating voltages, low cost (owing to abundant iron and fluorine), and structurally diverse crystalline forms such as pyrochlore and tungsten bronze types. These features make them strong contenders for next-generation high-energy, low-cost LIBs. This review highlights recent progress in iron-based fluoride cathode materials, with an emphasis on structural regulation and performance enhancement strategies. Using pyrochlore-type hydrated iron trifluoride (Fe2F5·H2O), synthesized via ionic liquids like BmimBF4, as a representative example, we discuss key methods for tuning physicochemical properties—such as electronic conductivity, ion diffusion, and structural stability—via doping, compositing, nanostructuring, and surface engineering. Advanced characterization tools (XRD, SEM/TEM, XPS, Raman, synchrotron radiation) and electrochemical analyses are used to reveal structure–property–performance relationships. Finally, we explore current challenges and future directions to guide the practical deployment of iron-based fluorides in LIBs. This review provides theoretical insights for designing high-performance, cost-effective cathode materials. Full article
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10 pages, 3245 KiB  
Communication
Effect of HfC Content on the Elevated-Temperature Ablation Behavior of W-HfC Composites
by Boyuan Zheng, Chaoqian Song, Yidong Wu, Zhong Du, Liye Du, Baohong Zhang and Xidong Hui
Metals 2025, 15(8), 925; https://doi.org/10.3390/met15080925 - 21 Aug 2025
Abstract
The effects of HfC content on the ablation resistance of W-HfC composites were systematically studied. The oxy-acetylene flame ablation test was conducted at 2800 °C. Post-ablation samples were characterized via XRD, section morphology, and EDS. W-10HfC showed the best ablation resistance, with a [...] Read more.
The effects of HfC content on the ablation resistance of W-HfC composites were systematically studied. The oxy-acetylene flame ablation test was conducted at 2800 °C. Post-ablation samples were characterized via XRD, section morphology, and EDS. W-10HfC showed the best ablation resistance, with a linear ablation rate of just 0.0175 mm/s. This enhanced performance is attributed to the formation of a dense HfW2O8 oxide layer with negative thermal expansion properties, reinforced by uniformly dispersed blocky HfO2 particles. However, excessive HfC content induces a stratified oxide structure. The thermal expansion coefficient mismatch between HfW2O8 and HfO2 causes microcrack formation, ultimately degrading ablation resistance. These findings establish critical guidelines for HfC content optimization in W-HfC composite design. Full article
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18 pages, 6936 KiB  
Article
Anisotropic Behavior in Microstructures and Properties of Refractory Tungsten Metal Produced by Laser Powder Bed Fusion
by Jinguo Ge, Heming Wu, Hongsen Liu, Yanan Zhu, Yan Chen, Wangwei Zhan, Liang Zhang and Zhuming Liu
Materials 2025, 18(16), 3910; https://doi.org/10.3390/ma18163910 - 21 Aug 2025
Abstract
This work employed laser powder bed fusion (LPBF) technology to prepare pure tungsten (W) metal components and investigated their internal defects, microstructural characteristics and mechanical properties within the horizontal and vertical planes to evaluate their anisotropic behavior. The steep temperature gradient and extremely [...] Read more.
This work employed laser powder bed fusion (LPBF) technology to prepare pure tungsten (W) metal components and investigated their internal defects, microstructural characteristics and mechanical properties within the horizontal and vertical planes to evaluate their anisotropic behavior. The steep temperature gradient and extremely rapid cooling rate during the LPBF process caused the as-deposited W grains to grow in a columnar crystal structure along the vertical height direction, with cracks propagating along the high-angle grain boundaries (HAGBs). Although the near-equiaxed W grains within the horizontal plane were finer than the epitaxial grains within the vertical plane, the increased number of cracks within the horizontal plane weakened the fine-grained strengthening effect, resulting in lower hardness and wear resistance within the horizontal plane than within the vertical plane. The wear behavior transformed from a comprehensive wear mechanism involving delamination wear and abrasive wear within the vertical plane to an abrasive wear mechanism with slight adhesive wear within the horizontal plane. The reported results demonstrate that the anisotropic behavior of hardness and wear resistance within the different deposition planes was mainly attributed to the differences in microstructure and crack distribution between the horizontal and vertical planes of LPBF-fabricated W parts. Full article
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12 pages, 13126 KiB  
Article
Wear Characteristics of WC-Co Cutting Tools Obtained by the U-FAST Method During Particleboard Milling
by Joanna Wachowicz, Zbigniew Bałaga and Piotr Podziewski
Materials 2025, 18(16), 3907; https://doi.org/10.3390/ma18163907 - 21 Aug 2025
Abstract
This article presents the wear characteristics of the working surface of WC-Co (Tungsten Carbide–Cobalt) tungsten carbide tools obtained using the innovative U-FAST (Upgraded Field-Assisted Sintering Technology) method for particleboard machining. Three groups of tools with a similar chemical composition but differing WC (Tungsten [...] Read more.
This article presents the wear characteristics of the working surface of WC-Co (Tungsten Carbide–Cobalt) tungsten carbide tools obtained using the innovative U-FAST (Upgraded Field-Assisted Sintering Technology) method for particleboard machining. Three groups of tools with a similar chemical composition but differing WC (Tungsten Carbide) grain sizes were tested. Milling tests were carried out on a CNC (Computer Numerical Control) machine tool with the following cutting parameters: spindle rotation at 15,000 rpm, a feed rate of 0.25 mm per tooth, and a feed rate of 3.75. The experimental results show that tools with submicron WC grit sizes of 0.4 µm and 0.8 µm have the longest tool life. Wear of the cutting edges occurred through the removal of the cobalt bond between the tungsten carbide grains, leading to fracture and mechanical removal of the grains from the cutting edge surface. The similarities in the relative wear characteristics of blades with submicron tungsten carbide grain sizes suggest that micro-abrasion and bond phase extrusion may be the main wear mechanisms under the experimental conditions. Nanometric WC grain size significantly influences tool wear through chipping and cracking. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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14 pages, 2536 KiB  
Article
Geochemistry and Genetic Significance of Scheelite in the Nanwenhe Tungsten Deposit, Yunnan Province, Southwestern China
by Wei Wang, Shao-Yong Jiang, Kexin Wang, Yu-Ying Che and Shugang Xiao
Minerals 2025, 15(8), 875; https://doi.org/10.3390/min15080875 - 20 Aug 2025
Viewed by 26
Abstract
The Nanwenhe tungsten deposit is located in the southeastern Yunnan Laojunshan mineral district and is hosted in the Paleoproterozoic Mengsong Group strata. It can be divided into two periods and four stages: skarn (early and late) and the vein type (feldspar–quartz–scheelite–tourmaline and calcite. [...] Read more.
The Nanwenhe tungsten deposit is located in the southeastern Yunnan Laojunshan mineral district and is hosted in the Paleoproterozoic Mengsong Group strata. It can be divided into two periods and four stages: skarn (early and late) and the vein type (feldspar–quartz–scheelite–tourmaline and calcite. There are two types of scheelite occurrences: one in skarn (Sch-1) and the other in feldspar–quartz–scheelite–tourmaline veins (Sch-2). The latter is further divided into two types: Sch-2a and Sch-2b. The REE content and Eu anomaly of skarn scheelite (Sch-1) are affected by early mineral crystallization; Sch-2a in feldspar–quartz–scheelite–tourmaline veins forms in a Na+-rich environment, and Eu2+ released into the fluid through hydrolysis may have largely entered tourmaline, resulting in the weak positive Eu anomaly of Sch-2a; the negative Eu anomaly of Sch-2b is likely inherited from the metamorphic fluid. The mineralization is likely closely related to the metamorphic fluid activity generated by the tensional structural environment at the end and after the regional uplift, forming ore by reducing fluids associated with regional metamorphism. The Laojunshan mineral district hosts several tungsten and tin polymetallic deposits and occurrences that share similar geological characteristics with the Nanwenhe tungsten deposit. No granite bodies related to mineralization have been identified within the mining area. Therefore, research on the genesis of the Nanwenhe tungsten deposit holds significant value for guiding exploration efforts. Full article
(This article belongs to the Special Issue Recent Developments in Rare Metal Mineral Deposits)
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19 pages, 7946 KiB  
Article
Synergistic Disinfection of Photocatalytic Nanomaterials Exposed to UVC, Electricity and Magnetic Fields Against Candida albicans
by María Cristina Grijalva-Castillo, Renee Joselin Saénz-Hernández, Adrián Alberto Cobos-Márquez, Francisco Alonso Herrera-Ojeda, Fernando Efraín Díaz-Chávez, Irving Ricardo Acosta-Galindo, César Leyva-Porras, Alva Rocío Castillo-González, María Alejandra Favila-Pérez, Celia María Quiñonez-Flores, Javier Camarillo Cisneros and Carlos Arzate-Quintana
Coatings 2025, 15(8), 968; https://doi.org/10.3390/coatings15080968 - 19 Aug 2025
Viewed by 197
Abstract
Nosocomial infections caused by Candida albicans pose serious challenges to healthcare systems due to their persistence on medical surfaces and resistance to conventional disinfectants. This study evaluates antifungal properties of SnO2 doped with silver and cuprite nanoparticles and WO3 thin films, [...] Read more.
Nosocomial infections caused by Candida albicans pose serious challenges to healthcare systems due to their persistence on medical surfaces and resistance to conventional disinfectants. This study evaluates antifungal properties of SnO2 doped with silver and cuprite nanoparticles and WO3 thin films, as well as cobalt (CoFe2O4) and cobalt–nickel (Co0.5Ni0.5Fe2O4) ferrite nanoparticles, activated by ultraviolet C (UVC) radiation, direct electric current (up to 100 V), and magnetic fields. SnO2 films were synthesized by Spray Pyrolysis and WO3 by Sputtering deposition, Ferrites nanoparticles by sol–gel, while metallic nanoparticles were synthetized via chemical reduction. Characterization consisted mainly of SEM, TEM, and XRD, and their antimicrobial activity was tested against C. albicans. WO3 films achieved 86.2% fungal inhibition after 5 min of UVC exposure. SnO2 films doped with nanoparticles reached 100% inhibition when combined with UVC and 100 V. Ferrite nanoparticles alone showed moderate activity (21.9%–40.4%) but exhibited strong surface adhesion to fungal cells, indicating potential for magnetically guided antifungal therapies. These results demonstrate the feasibility of using multifunctional nanomaterials for rapid, non-chemical disinfection. The materials are low-cost, scalable, and adaptable to hospital settings, making them promising candidates for reducing healthcare-associated fungal infections through advanced surface sterilization technologies. Full article
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16 pages, 4749 KiB  
Article
High Thermal Conductivity Diamond–Copper Composites Prepared via Hot Pressing with Tungsten–Coated Interfacial Layer Optimization
by Qiang Wang, Zhijie Ye, Lei Liu, Jie Bai, Yuning Zhao, Qiang Hu, Hong Liu, Lang Hu, Xiaodong Guo, Yongneng Xiao, Wenxin Cao and Zhenhuai Yang
Materials 2025, 18(16), 3882; https://doi.org/10.3390/ma18163882 - 19 Aug 2025
Viewed by 111
Abstract
Diamond–copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to [...] Read more.
Diamond–copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to reach optimal levels. In this study, tungsten was deposited on the surface of diamond particles by magnetron sputtering as an interfacial transition layer, and hot-press sintering was employed to fabricate the composites. The findings reveal that with prolonged annealing time, tungsten gradually transformed into W2C and WC, significantly enhancing interfacial bonding strength. When the diamond volume content was 50% and the interfacial coating consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W2C, the composite exhibited a thermal conductivity of 640 W/(m·K), the highest value reported among hot-press sintered composites with diamond content below 50%. Additionally, the AMM (Acoustic Mismatch Model) and DMM (Diffusion Mismatch Model) models were utilized to calculate the interfacial thermal conductance between different phases, identifying the optimal interfacial structure as diamond/W2C/WC/W2C/Cu. This composite material shows potential for application in high-power electronic device cooling, thermal management systems, and thermoelectric conversion, providing a more efficient thermal dissipation solution for related devices. Full article
(This article belongs to the Section Advanced Composites)
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22 pages, 7533 KiB  
Article
Theoretical Investigation of Ca2+ Intercalation in WS2 as a Negative Electrode Material for Calcium-Ion Batteries: Supported by Experimental Evaluation
by Seunga Yang, SangYup Lee, Paul Maldonado Nogales, Yangsoo Kim and Soon-Ki Jeong
Int. J. Mol. Sci. 2025, 26(16), 8005; https://doi.org/10.3390/ijms26168005 - 19 Aug 2025
Viewed by 143
Abstract
Tungsten disulfide (WS2), a two-dimensional layered material with favorable electronic properties, has been explored as a promising negative electrode material for calcium-ion batteries (CIBs). Despite its use in monovalent systems, its performance in divalent Ca2+ intercalation remains poorly understood. Herein, [...] Read more.
Tungsten disulfide (WS2), a two-dimensional layered material with favorable electronic properties, has been explored as a promising negative electrode material for calcium-ion batteries (CIBs). Despite its use in monovalent systems, its performance in divalent Ca2+ intercalation remains poorly understood. Herein, a combined theoretical and experimental framework is used to elucidate the electronic mechanisms underlying Ca2+ intercalation. Theoretical insights were obtained through density functional theory calculations, incorporating periodic simulations using the Vienna Ab initio Simulation Package, and localized orbital-level analysis using the discrete variational Xα method. These approaches reveal that Ca2+ insertion induces significant interlayer expansion, lowers diffusion barriers, and narrows the bandgap compared to Li+. Orbital analysis revealed strengthened W–S bonding and diminished antibonding interactions, which may contribute to the improved structural resilience. Electrochemical tests validated these predictions; the CaWS2 electrode delivered an initial discharge capacity of 208 mAh·g−1 at 0.1C, with 61% retention after 50 cycles at 1C. The voltage profile exhibits a distinct plateau near 0.7 V, consistent with a two-phase-like intercalation mechanism, contrasting with the gradual slope observed for Li+. These findings suggest that Ca2+ intercalation facilitates both rapid ion transport and enhanced structural robustness. This study offers mechanistic insights into multivalent-ion storage and supports the design of high-performance CIB electrodes. Full article
(This article belongs to the Special Issue Molecular Advances in Electrochemical Materials)
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18 pages, 992 KiB  
Article
Multi-Criteria Optimization of Yarn Guide Manufacturing Processes
by Aleksandra Jarco, Stanisław Płonka and Piotr Zyzak
Appl. Sci. 2025, 15(16), 9055; https://doi.org/10.3390/app15169055 - 17 Aug 2025
Viewed by 212
Abstract
Due to the insufficient durability (wear resistance) of guides made of 50SiCr4 steel tempered to a hardness of 400 HB, 14 variants of the yarn guide manufacturing process were developed. The ring spinner yarn guides were manufactured from three types of steel, from [...] Read more.
Due to the insufficient durability (wear resistance) of guides made of 50SiCr4 steel tempered to a hardness of 400 HB, 14 variants of the yarn guide manufacturing process were developed. The ring spinner yarn guides were manufactured from three types of steel, from Al99.5% and its alloys, as well as from porcelain, Al2O3 sinter, and WC 94% + Co 6% tungsten carbide. The unit manufacturing cost and six manufacturing quality criteria were used as evaluation criteria: four parameters of the geometric structure of the surface and the maximum surface hardness, as well as the depth of hardening of the surface layer. The presented variants were then evaluated against the seven criteria, determining a set of optimal solutions in the Pareto sense. This set consisted of 12 variants. A distance function was then used to select the best manufacturing process variant, corresponding to the smallest value of the distance function. In this study, this is the process variant for which the semi-finished product is a drawn bar ø6 mm of C45 steel tempered to a hardness of 350 HB with a glazed porcelain insert. The alternative process, with a slightly higher distance function value, is the variant with the Al2O3 ceramic sinter insert. Full article
(This article belongs to the Section Mechanical Engineering)
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19 pages, 11294 KiB  
Article
Study of Microstructure, Mechanical, and Corrosion Properties of K-TIG Welded Joints of 2205/316L Dissimilar Stainless Steel
by Shuwan Cui, Hongchen Li, Baoyan Zhang, Xiaozhen Liu and Ganli Mo
Metals 2025, 15(8), 910; https://doi.org/10.3390/met15080910 - 16 Aug 2025
Viewed by 167
Abstract
Stainless steel welding plays a critical role in industrial manufacturing due to its superior corrosion resistance and structural reliability. The keyhole tungsten inert gas (K-TIG) welding, renowned for its high efficiency, high precision, and cost-effectiveness, demonstrates particular advantages in medium-to-thick plate joining. In [...] Read more.
Stainless steel welding plays a critical role in industrial manufacturing due to its superior corrosion resistance and structural reliability. The keyhole tungsten inert gas (K-TIG) welding, renowned for its high efficiency, high precision, and cost-effectiveness, demonstrates particular advantages in medium-to-thick plate joining. In order to synergistically leverage the properties of 2205 duplex stainless steel (DSS) and 316L austenitic stainless steel (ASS), we have implemented K-TIG welding with a single variable under control: a constant current and voltage travelling speeds spanning 280–360 mm/min. Defect-free dissimilar joints were consistently achieved within the 280–320 mm/min speed window. The effects of welding speed on microstructural characteristics, mechanical properties, and corrosion behavior of the weld seams were systematically investigated. The percentage of austenite in the weld zone decreases from 84.7% to 59.9% as the welding speed increases. At a welding speed of 280 mm/min, the microstructural features in the regions near the weld seam and fusion zone were investigated. All obtained joints exhibited excellent tensile properties, with their tensile strengths surpassing those of the 316L base metal. The optimal impact toughness of 142 J was achieved at a welding speed of 320 mm/min. The obtained joints exceeded the hardness of TIG joints by 19%. Notably, the grain refinement in the weld zone not only enhanced the hardness of the welded joint but also improved its corrosion resistance. This study provides valuable process references in dissimilar stainless steel K-TIG welding applications. Full article
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17 pages, 41138 KiB  
Article
Study on Microstructure and Properties of K-TIG Welded Joint of 95 mm Ti-6Al-4V Thick Plate
by Yinqing Gong, Songxiao Hui, Yang Yu, Zhihao Zhang, Xiongyue Ye, Wenjun Ye and Zhongliang Wang
Materials 2025, 18(16), 3848; https://doi.org/10.3390/ma18163848 - 16 Aug 2025
Viewed by 303
Abstract
This study investigates the application of the Keyhole–Tungsten Inert Gas Welding (K-TIG) hot-wire filling welding technique with mechanical arc oscillation to weld a 95 mm-thick Ti-6Al-4V titanium alloy plate. The root layer thickness achieved with this technique reaches up to 17 mm, with [...] Read more.
This study investigates the application of the Keyhole–Tungsten Inert Gas Welding (K-TIG) hot-wire filling welding technique with mechanical arc oscillation to weld a 95 mm-thick Ti-6Al-4V titanium alloy plate. The root layer thickness achieved with this technique reaches up to 17 mm, with an average filling thickness of 2.5 mm. The weld bead displays a smooth, shiny appearance, and no significant welding defects are observed in the cross-section of the welded joint. Experimental results show that the welded joint consists of the α phase in different forms, as well as fine α+β microstructures. Compared to the base material, both the weld metal and the heat-affected zone exhibit a lower crystallographic texture strength, with more complex texture types. The impact toughness of the welded joint is excellent, with no significant weaknesses. The impact toughness of the weld metal significantly surpasses that of both the base material and the heat-affected zone. The engagement strengthening effect induced by high-current filling plays a crucial role in enhancing the impact toughness of the weld metal. Full article
(This article belongs to the Section Metals and Alloys)
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20 pages, 7249 KiB  
Article
Enhanced Degradation of 4-Nitrophenol via a Two-Stage Co-Catalytic Fenton Packed-Bed Reactor with External Circulation
by Yan Liu, Jingyu Liu, Yongyou Hu, Yueyue Shi, Chaoyang Tang, Jianhua Cheng, Xiaoqiang Zhu, Guobin Wang and Jieyun Xie
Environments 2025, 12(8), 280; https://doi.org/10.3390/environments12080280 - 14 Aug 2025
Viewed by 349
Abstract
To mitigate the consumption of active sites on co-catalysts by H2O2 and to enhance the efficiency and stability of co-catalytic Fenton reactions, an external circulation two-stage packed-bed reactor (ECTPBR) was developed using DPW (diatomite plate@polydopamine@WC) as a co-catalyst to degrade [...] Read more.
To mitigate the consumption of active sites on co-catalysts by H2O2 and to enhance the efficiency and stability of co-catalytic Fenton reactions, an external circulation two-stage packed-bed reactor (ECTPBR) was developed using DPW (diatomite plate@polydopamine@WC) as a co-catalyst to degrade 4-nitrophenol (4-NP). Under suitable conditions, the ECTPBR could achieve over 91.97% 4-NP degradation, with low iron sludge production (11.97 mg/L) and minimal tungsten leaching (3.6363 mg/L). The two-stage strategy enabled spatial separation of Fe3+ reduction and Fenton reactions, minimizing the loss of active sites on DPW, ensuring long-term system stability, and reducing the toxicity of 4-NPdegradation products. In addition, external circulation enhanced mass transfer and improved resistance to shock loads. These advantages suggest that the ECTPBR may serve as an effective strategy for applying co-catalytic Fenton reactions in the treatment of toxic and refractory organic wastewater. Full article
(This article belongs to the Special Issue Advances in Heavy Metal Remediation Technologies)
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16 pages, 4680 KiB  
Article
Combined Approach to the Synthesis of WC-(Fe, Ni) Hard Alloys: Mechanical Activation and Spark Plasma Sintering
by Gulzhaz Uazyrkhanova, Yernat Kozhakhmetov, Madina Aidarova, Małgorzata Rutkowska-Gorczyca and Yerkezhan Tabiyeva
Crystals 2025, 15(8), 724; https://doi.org/10.3390/cryst15080724 - 14 Aug 2025
Viewed by 212
Abstract
This paper presents a combined approach to the synthesis of WC-(Fe, Ni) hard alloys obtained by mechanical activation and spark plasma sintering (SPS). The main attention at this stage of the work is paid to studying the evolution of the morphology and phase [...] Read more.
This paper presents a combined approach to the synthesis of WC-(Fe, Ni) hard alloys obtained by mechanical activation and spark plasma sintering (SPS). The main attention at this stage of the work is paid to studying the evolution of the morphology and phase composition of WC-(Fe, Ni) powder mixtures during high-energy milling and their subsequent sintering by the SPS method. The study analyzed the effect of the mechanosynthesis time and the binder phase content on the change in the average particle size, the degree of defect formation, and the phase composition of the powders. It was found that an increase in the milling time to 240 min promotes the formation of the WC nanocrystalline structure and the accumulation of microdefects, which is accompanied by a decrease in the average particle size and an increase in the dislocation density. The X-ray phase analysis of the samples after SPS confirmed the preservation of the WC phase and the formation of the γ-(Fe, Ni) matrix without the formation of secondary carbide phases. The analysis of sample shrinkage showed three main stages: initial compaction, intense shrinkage, and structure stabilization. The obtained data demonstrate that optimization of the parameters of mechanical activation and SPS allow for effective control of the phase composition and morphology of WC-(Fe, Ni) powders, which opens up opportunities for their subsequent study in conditions of aggressive environments and radiation exposure. Full article
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20 pages, 4898 KiB  
Review
Advanced Progress of Non-Stoichiometric Transition Metal Sulfides for Sensing, Catalysis, and Energy Storage
by Xuyang Xu, Mengyang Zhang, Jincheng Wu, Ziyan Shen, Yang Liu and Longlu Wang
Nanomaterials 2025, 15(16), 1237; https://doi.org/10.3390/nano15161237 - 13 Aug 2025
Viewed by 223
Abstract
Beyond the extensively studied two-dimensional transition metal dichalcogenides, a wide range of non-stoichiometric transition metal sulfides, such as molybdenum sulfides and tungsten sulfides (Mo2S3, W2S3, Mo6S8, Mo6S6, [...] Read more.
Beyond the extensively studied two-dimensional transition metal dichalcogenides, a wide range of non-stoichiometric transition metal sulfides, such as molybdenum sulfides and tungsten sulfides (Mo2S3, W2S3, Mo6S8, Mo6S6, NiMo3S4), have attracted significant attention for their promising applications in sensing, catalysis, and energy storage. It is necessary to review the current advanced progress of non-stoichiometric transition metal sulfides for various applications. Here, we systematically summarize the synthesis strategies of the non-stoichiometric transition metal sulfides, encompassing methods such as the molten salt synthesis method, high-metal-content growth strategy, and others. Particular emphasis is placed on how variations in the metal-to-sulfur ratio give rise to distinct crystal structures and electronic properties, and how these features influence their conductivity, stability, and performance. This review will deepen the understanding of the state of the art of non-stoichiometric transition metal sulfides, including the synthesis, characterization, modification, and various applications. Full article
(This article belongs to the Special Issue Pioneering Nanomaterials: Revolutionizing Energy and Catalysis)
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