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Search Results (992)

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Keywords = modified carbon nanotubes

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15 pages, 1619 KiB  
Article
Reducing Energy Penalty in Wastewater Treatment: Fe-Cu-Modified MWCNT Electrodes for Low-Voltage Electrofiltration of OMC
by Lu Yu, Jun Zeng, Xiu Fan, Fengxiang Li and Tao Hua
Energies 2025, 18(15), 4077; https://doi.org/10.3390/en18154077 - 1 Aug 2025
Viewed by 164
Abstract
Pseudo-persistent organic pollutants, such as pharmaceuticals, personal care products (PPCPs), and organic dyes, are a major issue in current environmental engineering. Considering the limitations of traditional wastewater treatment plant methods and degradation technologies for organic pollutants, the search for new technologies more suitable [...] Read more.
Pseudo-persistent organic pollutants, such as pharmaceuticals, personal care products (PPCPs), and organic dyes, are a major issue in current environmental engineering. Considering the limitations of traditional wastewater treatment plant methods and degradation technologies for organic pollutants, the search for new technologies more suitable for treating these new types of pollutants has become a research hotspot in recent years. Membrane filtration, adsorption, advanced oxidation, and electrochemical advanced oxidation technologies can effectively treat new organic pollutants. The electro-advanced oxidation process based on sulfate radicals is renowned for its non-selectivity, high efficiency, and environmental friendliness, and it can improve the dewatering performance of sludge after wastewater treatment. Therefore, in this study, octyl methoxycinnamate (OMC) was selected as the target pollutant. A new type of electrochemical filtration device based on the advanced oxidation process of sulfate radicals was designed, and a new type of modified carbon nanotube material electrode was synthesized to enhance its degradation effect. In a mixed system of water and acetonitrile, the efficiency of the electrochemical filtration device loaded with the modified electrode for degrading OMC is 1.54 times that at room temperature. The experimental results confirmed the superiority and application prospects of the self-designed treatment scheme for organic pollutants, providing experience and a reference for the future treatment of PPCP pollution. Full article
(This article belongs to the Section D2: Electrochem: Batteries, Fuel Cells, Capacitors)
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20 pages, 4901 KiB  
Article
Study on the Adaptability of FBG Sensors Encapsulated in CNT-Modified Gel Material for Asphalt Pavement
by Tengteng Guo, Xu Guo, Yuanzhao Chen, Chenze Fang, Jingyu Yang, Zhenxia Li, Jiajie Feng, Jiahua Kong, Haijun Chen, Chaohui Wang, Qian Chen and Jiachen Wang
Gels 2025, 11(8), 590; https://doi.org/10.3390/gels11080590 - 31 Jul 2025
Viewed by 139
Abstract
To prolong the service life of asphalt pavement and reduce its maintenance cost, a fiber Bragg grating (FBG) sensor encapsulated in carboxylated carbon nanotube (CNT-COOH)-modified gel material suitable for strain monitoring of asphalt pavement was developed. Through tensile and bending tests, the effects [...] Read more.
To prolong the service life of asphalt pavement and reduce its maintenance cost, a fiber Bragg grating (FBG) sensor encapsulated in carboxylated carbon nanotube (CNT-COOH)-modified gel material suitable for strain monitoring of asphalt pavement was developed. Through tensile and bending tests, the effects of carboxylated carbon nanotubes on the mechanical properties of gel materials under different dosages were evaluated and the optimal dosage of carbon nanotubes was determined. Infrared spectrometer and scanning electron microscopy were used to compare and analyze the infrared spectra and microstructure of carbon nanotubes before and after carboxyl functionalization and modified gel materials. The results show that the incorporation of CNTs-COOH increased the tensile strength, elongation at break, and tensile modulus of the gel material by 36.2%, 47%, and 17.2%, respectively, and increased the flexural strength, flexural modulus, and flexural strain by 89.7%, 7.5%, and 63.8%, respectively. Through infrared spectrum analysis, it was determined that carboxyl (COOH) and hydroxyl (OH) were successfully introduced on the surface of carbon nanotubes. By analyzing the microstructure, it can be seen that the carboxyl functionalization of CNTs improved the agglomeration of carbon nanotubes. The tensile section of the modified gel material is rougher than that of the pure epoxy resin, showing obvious plastic deformation, and the toughness is improved. According to the data from the calibration experiment, the strain and temperature sensitivity coefficients of the packaged sensor are 1.9864 pm/μm and 0.0383 nm/°C, respectively, which are 1.63 times and 3.61 times higher than those of the bare fiber grating. The results of an applicability study show that the internal structure strain of asphalt rutting specimen changed linearly with the external static load, and the fitting sensitivity is 0.0286 με/N. Combined with ANSYS finite element analysis, it is verified that the simulation analysis results are close to the measured data, which verifies the effectiveness and monitoring accuracy of the sensor. The dynamic load test results reflect the internal strain change trend of asphalt mixture under external rutting load, confirming that the encapsulated FBG sensor is suitable for the long-term monitoring of asphalt pavement strain. Full article
(This article belongs to the Special Issue Synthesis, Properties, and Applications of Novel Polymer-Based Gels)
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23 pages, 9108 KiB  
Article
COx-Free Hydrogen Production via CH4 Decomposition on Alkali-Incorporated (Mg, La, Ca, Li) Ni-Al Catalysts
by Morgana Rosset, Yan Resing Dias, Liliana Amaral Féris and Oscar William Perez-Lopez
Nanoenergy Adv. 2025, 5(3), 10; https://doi.org/10.3390/nanoenergyadv5030010 - 30 Jul 2025
Viewed by 174
Abstract
The catalytic decomposition of CH4 is a promising method for producing high-purity COx-free hydrogen. A Ni-Al-LDH catalyst synthesized via coprecipitation was modified with alkali metals (Mg, La, Ca, or Li) through reconstruction to enhance catalytic activity and resistance to deactivation [...] Read more.
The catalytic decomposition of CH4 is a promising method for producing high-purity COx-free hydrogen. A Ni-Al-LDH catalyst synthesized via coprecipitation was modified with alkali metals (Mg, La, Ca, or Li) through reconstruction to enhance catalytic activity and resistance to deactivation during catalytic methane decomposition (CMD). The catalysts were evaluated by two activation methods: H2 reduction and direct heating with CH4. The MgNA-R catalyst achieved the highest CH4 conversion (65%) at 600 °C when reduced with H2, attributed to a stronger Ni-Al interaction. Under CH4 activation, LaNA-C achieved a 55% conversion at the same temperature, associated with a smaller crystallite size and higher reducibility due to La incorporation. Although all catalysts deactivated due to carbon deposition and/or sintering, LaNA-C was the only sample that could resist deactivation for a longer period, as La appears to have a protective effect on the active phase. Post-reaction characterizations revealed the formation of graphitic and filamentous carbon. Raman spectroscopy exhibited a higher degree of graphitization and structural order in LaNA-C, whereas SEM showed a more uniform distribution of carbon filaments. TEM confirmed the presence of multi-walled carbon nanotubes with encapsulated Ni particles in La-promoted samples. These results demonstrate that La addition improves the catalytic performance under CH4 activation and carbon structure. This finding offers a practical advantage for CMD processes, as it reduces or eliminates the need to use hydrogen during catalyst activation. Full article
(This article belongs to the Special Issue Novel Energy Materials)
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26 pages, 4449 KiB  
Review
Recent Progress in Electrocatalysts for Hydroquinone Electrochemical Sensing Application
by Mohammad Aslam, Khursheed Ahmad, Saood Ali, Khaled Hamdy and Danishuddin
Biosensors 2025, 15(8), 488; https://doi.org/10.3390/bios15080488 - 28 Jul 2025
Viewed by 357
Abstract
This review article compiled previous reports in the fabrication of hydroquinone (HQ) electrochemical sensors using differently modified electrodes. The electrode materials, which are also called electrocatalysts, play a crucial role in electrochemical detection of biomolecules and toxic substances. Metal oxides, MXenes, carbon-based materials [...] Read more.
This review article compiled previous reports in the fabrication of hydroquinone (HQ) electrochemical sensors using differently modified electrodes. The electrode materials, which are also called electrocatalysts, play a crucial role in electrochemical detection of biomolecules and toxic substances. Metal oxides, MXenes, carbon-based materials such as reduced graphene oxide (rGO), carbon nanotubes (CNTs), layered double hydroxides (LDH), metal sulfides, and hybrid composites were extensively utilized in the fabrication of HQ sensors. The electrochemical performance, including limit of detection, linearity, sensitivity, selectivity, stability, reproducibility, repeatability, and recovery for real-time sensing of the HQ sensors have been discussed. The limitations, challenges, and future directions are also discussed in the conclusion section. It is believed that the present review article may benefit researchers who are involved in the development of HQ sensors and catalyst preparation for electrochemical sensing of other toxic substances. Full article
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14 pages, 3187 KiB  
Article
Characterizations of Electrospun PVDF-Based Mixed Matrix Membranes with Nanomaterial Additives
by Haya Taleb, Venkatesh Gopal, Sofian Kanan, Raed Hashaikeh, Nidal Hilal and Naif Darwish
Nanomaterials 2025, 15(15), 1151; https://doi.org/10.3390/nano15151151 - 25 Jul 2025
Viewed by 336
Abstract
Water scarcity poses a formidable challenge around the world, especially in arid regions where limited availability of freshwater resources threatens both human well-being and ecosystem sustainability. Membrane-based desalination technologies offer a viable solution to address this issue by providing access to clean water. [...] Read more.
Water scarcity poses a formidable challenge around the world, especially in arid regions where limited availability of freshwater resources threatens both human well-being and ecosystem sustainability. Membrane-based desalination technologies offer a viable solution to address this issue by providing access to clean water. This work ultimately aims to develop a novel permselective polymeric membrane material to be employed in an electrochemical desalination system. This part of the study addresses the optimization, preparation, and characterization of a polyvinylidene difluoride (PVDF) polymeric membrane using the electrospinning technique. The membranes produced in this work were fabricated under specific operational, environmental, and material parameters. Five different additives and nano-additives, i.e., graphene oxide (GO), carbon nanotubes (CNTs), zinc oxide (ZnO), activated carbon (AC), and a zeolitic imidazolate metal–organic framework (ZIF-8), were used to modify the functionality and selectivity of the prepared PVDF membranes. Each membrane was synthesized at two different levels of additive composition, i.e., 0.18 wt.% and 0.45 wt.% of the entire PVDF polymeric solution. The physiochemical properties of the prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), zeta potential, contact angle, conductivity, porosity, and pore size distribution. Based on findings of this study, PVDF/GO membrane exhibited superior results, with an electrical conductivity of 5.611 mS/cm, an average pore size of 2.086 µm, and a surface charge of −38.33 mV. Full article
(This article belongs to the Section Synthesis, Interfaces and Nanostructures)
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24 pages, 3701 KiB  
Article
Multifunctional REE Selective Hybrid Membranes Based on Ion-Imprinted Polymers and Modified Multiwalled Carbon Nanotubes: A Physicochemical Characterization
by Aleksandra Rybak, Aurelia Rybak, Sławomir Boncel, Anna Kolanowska, Waldemar Kaszuwara, Mariusz Nyc, Rafał Molak, Jakub Jaroszewicz and Spas D. Kolev
Int. J. Mol. Sci. 2025, 26(15), 7136; https://doi.org/10.3390/ijms26157136 - 24 Jul 2025
Viewed by 295
Abstract
A novel type of multifunctional hybrid membranes combining modified chitosan, functionalized multi-walled carbon nanotubes (MWCNTs), and rare earth element ion-imprinted polymers (REEIIPs) were designed and characterized. The synthesized materials were characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), [...] Read more.
A novel type of multifunctional hybrid membranes combining modified chitosan, functionalized multi-walled carbon nanotubes (MWCNTs), and rare earth element ion-imprinted polymers (REEIIPs) were designed and characterized. The synthesized materials were characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), X-ray micro-tomography, and Fourier transform infrared spectroscopy (FTIR). The hybrid membranes were also studied in terms of their mechanical and rheological properties. The key element of the proper preparation of hybrid membranes using the casting method in an external magnetic field was to synthesize membrane components with appropriate magnetic properties. It was found that they showed tunable weak ferromagnetic properties, and the increase in modified nanotube addition caused the rise in the membrane’s saturation magnetization, which for Nd-selective hybrid membranes reached 0.44 emu/g. Also, the increase in thermooxidative stability was noted after introducing functionalized nanotubes into polymer matrices, which, in the case of Gd-selective membranes, were stable even up to 730 °C. The rise in the modified MWCNT addition and selection of appropriate REE ion-imprinted polymers improved mechanical (Rm and E values increase even twice) and rheological parameters (almost double growth of E′ and E″ values) of the tested membranes. Synthesized hybrid membranes showed a high rejection of matrix components and an increase in retention ratio with rising MWCNT-REEIIP addition, ultimately reaching 94.35%, 92.12%, and 90.11% for Nd, Pr, and Gd, respectively. The performed analysis confirmed homogeneous dispersion, phase compatibility, network integration, formation of a complex 3D microstructure, and improved operational stability of created hybrid membranes, which is significant for their future applications in Nd, Pr, and Gd recovery from coal fly ash extracts. Full article
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25 pages, 6336 KiB  
Article
Treatment of Industrial Brine Using a Poly (Vinylidene Fluoride) Membrane Modified with Carbon Nanotubes
by Tshifhiwa T. Tshauambea, Soraya P. Malinga and Patrick G. Ndungu
Membranes 2025, 15(8), 220; https://doi.org/10.3390/membranes15080220 - 23 Jul 2025
Viewed by 381
Abstract
This study explores using polyvinylidene fluoride (PVDF) membranes modified with multi-walled carbon nanotubes (MWCNTs) to treat simulated and industrial brine from coal power stations. The MWCNTs were acid-treated and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Raman, and nitrogen sorption at 77 K, [...] Read more.
This study explores using polyvinylidene fluoride (PVDF) membranes modified with multi-walled carbon nanotubes (MWCNTs) to treat simulated and industrial brine from coal power stations. The MWCNTs were acid-treated and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Raman, and nitrogen sorption at 77 K, Thermogravimetric analysis (TGA), and Transmission electron microscopy (TEM). The desired membranes were obtained by casting from a solution of N-Methyl-2-pyrrolidone, PVDF, various weight percentages of MWCNTs, and a small amount of polyvinylpyrrolidone. The acid treatment of the MWCNTs introduced oxygen moieties on the surface, and increased pore volume and surface area while maintaining crystallinity and structural integrity remain preserved. The maximum rejection rate achieved was 41.82% with 1 wt.% of acid-treated MWCNTs in the PVDF membrane. Acid-treated MWCNTs loaded membranes had an improved rejection rate, which was 5× higher than membranes without MWCNTs. Full article
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15 pages, 8311 KiB  
Article
Enhanced Heat Transfer of 1-Octadecanol Phase-Change Materials Using Carbon Nanotubes
by Xiuli Wang, Qingmeng Wang, Xiaomin Cheng, Yi Yang, Xiaolan Chen and Qianju Cheng
Molecules 2025, 30(15), 3075; https://doi.org/10.3390/molecules30153075 - 23 Jul 2025
Viewed by 223
Abstract
Solid–liquid phase-change materials (PCMs) have attracted considerable attention in heat energy storage due to their appropriate phase-transition temperatures and high thermal storage density. The primary issues that need to be addressed in the wide application of traditional PCMs are easy leakage during solid–liquid [...] Read more.
Solid–liquid phase-change materials (PCMs) have attracted considerable attention in heat energy storage due to their appropriate phase-transition temperatures and high thermal storage density. The primary issues that need to be addressed in the wide application of traditional PCMs are easy leakage during solid–liquid phase transitions, low thermal conductivity, and poor energy conversion function. The heat transfer properties of PCMs can be improved by compounding with carbon materials. Carbon nanotubes (CNTs) are widely used in PCMs for heat storage because of their high thermal conductivity, strong electrical conductivity, and high chemical stability. This study investigates the thermal properties of 1-octadecanol (OD) modified with different diameters and amounts of CNTs using the melt blending method and the ultrasonic dispersion method. The aim is to enhance thermal conductivity while minimizing latent heat loss. The physical phase, microstructure, phase-change temperature, phase-transition enthalpy, thermal stability, and thermal conductivity of the OD/CNTs CPCMs were systematically studied using XRD, FTIR, SEM, DSC, and Hot Disk. Moreover, the heat charging and releasing performance of the OD/CNTs CPCMs was investigated through heat charging and releasing experiments, and the relationship among the composition–structure–performance of the CPCMs was established. Full article
(This article belongs to the Special Issue Energy Storage Materials: Synthesis and Application)
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13 pages, 1647 KiB  
Article
Electrochemical Sensing of Hg2+ Ions Using an SWNTs/Ag@ZnBDC Composite with Ultra-Low Detection Limit
by Gajanan A. Bodkhe, Bhavna Hedau, Mayuri S. More, Myunghee Kim and Mahendra D. Shirsat
Chemosensors 2025, 13(7), 259; https://doi.org/10.3390/chemosensors13070259 - 16 Jul 2025
Viewed by 351
Abstract
A novel single-walled carbon nanotube (SWNT), silver (Ag) nanoparticle, and zinc benzene carboxylate (ZnBDC) metal–organic framework (MOF) composite was synthesised and systematically characterised to develop an efficient platform for mercury ion (Hg2+) detection. X-ray diffraction confirmed the successful incorporation of Ag [...] Read more.
A novel single-walled carbon nanotube (SWNT), silver (Ag) nanoparticle, and zinc benzene carboxylate (ZnBDC) metal–organic framework (MOF) composite was synthesised and systematically characterised to develop an efficient platform for mercury ion (Hg2+) detection. X-ray diffraction confirmed the successful incorporation of Ag nanoparticles and SWNTs without disrupting the crystalline structure of ZnBDC. Meanwhile, field-emission scanning electron microscopy and energy-dispersive spectroscopy mapping revealed a uniform elemental distribution. Thermogravimetric analysis indicated enhanced thermal stability. Electrochemical measurements (cyclic voltammetry and electrochemical impedance spectroscopy) demonstrated improved charge transfer properties. Electrochemical sensing investigations using differential pulse voltammetry revealed that the SWNTs/Ag@ZnBDC-modified glassy carbon electrode exhibited high selectivity toward Hg2+ ions over other metal ions (Cd2+, Co2+, Cr3+, Fe3+, and Zn2+), with optimal performance at pH 4. The sensor displayed a linear response in the concentration range of 0.1–1.0 nM (R2 = 0.9908), with a calculated limit of detection of 0.102 nM, slightly close to the lowest tested point, confirming its high sensitivity for ultra-trace Hg2+ detection. The outstanding sensitivity, selectivity, and reproducibility underscore the potential of SWNTs/Ag@ZnBDC as a promising electrochemical platform for detecting trace levels of Hg2+ in environmental monitoring. Full article
(This article belongs to the Special Issue Green Electrochemical Sensors for Trace Heavy Metal Detection)
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15 pages, 2527 KiB  
Article
A Disposable SWCNTs/AuNPs-Based Screen-Printed ISE at Different Temperatures to Monitor Ca2+ for Hypocalcemia Diagnosis
by Zhixue Yu, Hui Wang, Yue He, Ruipeng Chen, Xiangfang Tang and Benhai Xiong
Chemosensors 2025, 13(7), 252; https://doi.org/10.3390/chemosensors13070252 - 12 Jul 2025
Viewed by 378
Abstract
In this paper, screen-printed ion-selective electrodes combined with single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs) were used to rapidly and accurately measure serum Ca2+ concentration. Due to the susceptibility of cows to hypocalcemia after delivery, this disease can affect the health [...] Read more.
In this paper, screen-printed ion-selective electrodes combined with single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs) were used to rapidly and accurately measure serum Ca2+ concentration. Due to the susceptibility of cows to hypocalcemia after delivery, this disease can affect the health of cows and reduce milk production. Therefore, the development of an economical and swift detection method holds paramount importance for facilitating early diagnosis and subsequent treatment. In this study, by combining the high electrical conductivity and large surface area of SWCNTs with the strong catalytic activity of AuNPs, a SWCNTs/AuNPs composite with high sensitivity and good stability was prepared, achieving efficient selective recognition and signal conversion of Ca2+. The experimental results indicate that the screen-printed electrode modified with SWCNTs/AuNPs exhibited excellent performance in the determination of Ca2+ concentration. Its linear response range is 10−5.5–10−1 M, covering the normal and pathological concentration range of Ca2+ in cow blood, and the detection limit is far below the clinical detection requirements. In addition, the electrode also has good anti-interference ability and fast response time (about 15 s), showing good performance in the range of 5–45 °C. In practical applications, the combination of the electrode and portable detection equipment can realize the field rapid determination of cow blood Ca2+ concentration. This method is easy to operate, cost-effective, and easy to promote, providing strong technical support for the health management of dairy farms. Full article
(This article belongs to the Section Electrochemical Devices and Sensors)
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27 pages, 5856 KiB  
Article
Buckypapers in Polymer-Based Nanocomposites: A Pathway to Superior Thermal Stability
by Johannes Bibinger, Sebastian Eibl, Hans-Joachim Gudladt and Philipp Höfer
Nanomaterials 2025, 15(14), 1081; https://doi.org/10.3390/nano15141081 - 11 Jul 2025
Viewed by 291
Abstract
The thermal stability of carbon fiber-reinforced plastic (CFRP) materials is constrained by the low thermal conductivity of its polymer matrix, resulting in inefficient heat dissipation, local overheating, and accelerated degradation during thermal loads. To overcome these limitations, composite materials can be modified with [...] Read more.
The thermal stability of carbon fiber-reinforced plastic (CFRP) materials is constrained by the low thermal conductivity of its polymer matrix, resulting in inefficient heat dissipation, local overheating, and accelerated degradation during thermal loads. To overcome these limitations, composite materials can be modified with buckypapers—thin, densely interconnected layers of carbon nanotubes (CNTs). In this study, sixteen 8552/IM7 prepreg plies were processed with up to nine buckypapers and strategically placed at various positions. The resulting nanocomposites were evaluated for manufacturability, material properties, and thermal resistance. The findings reveal that prepreg plies provide only limited matrix material for buckypaper infiltration. Nonetheless, up to five buckypapers, corresponding to 8 wt.% CNTs, can be incorporated into the material without inducing matrix depletion defects. This integration significantly enhances the material’s thermal properties while maintaining its mechanical integrity. The nanotubes embedded in the matrix achieve an effective thermal conductivity of up to 7 W/(m·K) based on theoretical modeling. As a result, under one-sided thermal irradiation at 50 kW/m2, thermo-induced damage and strength loss can be delayed by up to 20%. Therefore, thermal resistance is primarily determined by the nanotube concentration, whereas the arrangement of the buckypapers affects the material quality. Since this innovative approach enables the targeted integration of high particle fractions, it offers substantial potential for improving the safety and reliability of CFRP under thermal stress. Full article
(This article belongs to the Special Issue Advances in Nano-Enhanced Thermal Functional Materials)
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29 pages, 3791 KiB  
Article
Production of Sustainable Synthetic Natural Gas from Carbon Dioxide and Renewable Energy Catalyzed by Carbon-Nanotube-Supported Ni and ZrO2 Nanoparticles
by João Pedro Bueno de Oliveira, Mariana Tiemi Iwasaki, Henrique Carvalhais Milanezi, João Lucas Marques Barros, Arnaldo Agostinho Simionato, Bruno da Silva Marques, Carlos Alberto Franchini, Ernesto Antonio Urquieta-González, Ricardo José Chimentão, José Maria Corrêa Bueno, Adriana Maria da Silva and João Batista Oliveira dos Santos
Catalysts 2025, 15(7), 675; https://doi.org/10.3390/catal15070675 - 11 Jul 2025
Viewed by 483
Abstract
The production of synthetic natural gas in the context of power-to-gas is a promising technology for the utilization of CO2. Ni-based catalysts supported on carbon nanotubes (CNTs) were prepared through incipient wetness impregnation and characterized using N2 adsorption, X-ray diffraction [...] Read more.
The production of synthetic natural gas in the context of power-to-gas is a promising technology for the utilization of CO2. Ni-based catalysts supported on carbon nanotubes (CNTs) were prepared through incipient wetness impregnation and characterized using N2 adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and temperature-programmed reduction (TPR). The catalysts were tested for CO2 methanation in the 200–400 °C temperature range and at atmospheric pressure. The results demonstrated that the catalytic activity increased with the addition of the CNTs and Ni loading. The selectivity towards CH4 was close to 100% for the Ni/ZrO2/CNT catalysts. Reduction of the calcined catalyst at 500 °C using H2 modified the surface chemistry of the catalyst, leading to an increase in the Ni particles. The CO2 conversion was dependent on the Ni loading and the temperature reduction in the NiO species. The 10Ni/ZrO2/CNT catalyst was highly stable in CO2 methanation at 350 °C for 24 h. Thus, CNTs combined with Ni and ZrO2 were considered promising for use as catalysts in CO2 methanation at low temperatures. Full article
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27 pages, 690 KiB  
Review
Phthalocyanine-Modified Electrodes Used in the Electroanalysis of Monoamine Neurotransmitters
by Anton Alexandru Ciucu, Mihaela Buleandră, Dana Elena Popa and Dragoș Cristian Ștefănescu
Chemosensors 2025, 13(7), 243; https://doi.org/10.3390/chemosensors13070243 - 7 Jul 2025
Viewed by 532
Abstract
Metallo-phthalocyanines (MPcs) are versatile materials with applications in electroanalysis because of their superior catalytic properties. This review presents the electrochemical methods based on MPc-modified electrodes and reports some of their remarkable properties and applications in the electroanalysis of monoamine neurotransmitters and biomolecules that [...] Read more.
Metallo-phthalocyanines (MPcs) are versatile materials with applications in electroanalysis because of their superior catalytic properties. This review presents the electrochemical methods based on MPc-modified electrodes and reports some of their remarkable properties and applications in the electroanalysis of monoamine neurotransmitters and biomolecules that play a crucial role in vital functions of the human body. The development of electrocatalytic chemically modified electrodes is based on their ability to provide a selective and rapid response toward a specific analyte in complex media without the need for sample pretreatment. The explanation of several phenomena occurring at the MPc-modified electrode surface (e.g., MPc-mediated electrocatalysis), the advantages of promoting different electron transfer reactions, and the detection mechanism are also presented. The types of MPcs and different materials, such as carbon nanotubes and graphene, used as substrates for modified working electrodes are discussed. Modifying the properties of MPcs through various interactions, or combining MPcs with carbonaceous materials, creates a synergistic effect. Such hybrid materials present both extraordinary catalytic and increased conductivity properties. We conducted a compilation study based on recent works to demonstrate the efficacy of the developed sensors and methods in sensing monoamine neurotransmitters. We emphasize the analyte type, optimized experimental parameters, working range, limits of detection and quantification, and application to real samples. MPc–carbon hybrids have led to the development of sensors with superior sensitivity and improved selectivity, enabling the detection of analytes at lower concentrations. We highlight the main advantages and drawbacks of the discussed methods. This review summarizes recent progress in the development and application of metallo-phthalocyanine-modified electrodes in the electroanalysis of monoamine neurotransmitters. Some possible future trends are highlighted. Full article
(This article belongs to the Special Issue New Electrodes Materials for Electroanalytical Applications)
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19 pages, 3235 KiB  
Article
Electrochemical Detection of Bisphenol S Based on Molecularly Imprinted Polymers Grafted on Functionalized Multiwalled Carbon Nanotubes: A Facile Sensor Fabrication Approach
by Christopher Mwanza, Lin Zhao, Qing Zhang and Shou-Nian Ding
Chemosensors 2025, 13(7), 236; https://doi.org/10.3390/chemosensors13070236 - 30 Jun 2025
Viewed by 430
Abstract
Bisphenol S (BPS), a key ingredient in polycarbonate plastics and epoxy resins, is a known endocrine-disrupting compound that poses significant risks to human health and the environment. As such, the development of rapid and reliable analytical techniques for its detection is essential. In [...] Read more.
Bisphenol S (BPS), a key ingredient in polycarbonate plastics and epoxy resins, is a known endocrine-disrupting compound that poses significant risks to human health and the environment. As such, the development of rapid and reliable analytical techniques for its detection is essential. In this work, we present a newly engineered electrochemical sensor designed for the sensitive and selective detection of BPS using a straightforward and effective fabrication approach. The sensor was constructed by grafting molecularly imprinted polymers (MIPs) onto vinyl-functionalized multiwalled carbon nanotubes (f-MWCNTs). Ethylene glycol dimethacrylate and acrylamide were used as the cross-linker and functional monomer, respectively, in the synthesis of the MIP layer. The resulting MIP@f-MWCNT nanocomposite was characterized using Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The MIP@f-MWCNT material was then combined with chitosan, a biocompatible binder, to fabricate the final MIP@f-MWCNT/chitosan-modified glassy carbon electrode (GCE). Electrochemical evaluation showed a broad linear detection range from 1 to 60 µM (R2 = 0.992), with a sensitivity of 0.108 µA/µM and a detection limit of 2.00 µM. The sensor retained 96.0% of its response after four weeks and exhibited high selectivity against structural analogues. In spiked plastic extract samples, recoveries ranged from 95.6% to 105.0%. This robust, cost-effective, and scalable sensing platform holds strong potential for environmental monitoring, food safety applications, and real-time electrochemical detection of endocrine-disrupting compounds like BPS. Full article
(This article belongs to the Special Issue Nanostructured Materials for Electrochemical Sensing)
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15 pages, 2316 KiB  
Article
Enhancement of Ethylene-Butene Terpolymer Performance via Carbon Nanotube-Induced Nanodispersion of Montmorillonite Layers
by Li Zhang, Jianming Liu, Duanjiao Li, Wenxing Sun, Zhi Li, Yongchao Liang, Qiang Fu, Nian Tang, Bo Zhang, Fei Huang, Xuelian Fan, Yuansi Wei, Pengxiang Bai and Yuqi Wang
Crystals 2025, 15(7), 612; https://doi.org/10.3390/cryst15070612 - 30 Jun 2025
Viewed by 247
Abstract
In this study, the enhancement mechanism of the nano-dispersion of stearic acid-modified montmorillonite (SMMT) induced by carbon nanotubes (CNTs) in ethylene-butene terpolymer (EBT) was comprehensively investigated, and the regulation effect of composite fillers on EBT properties was revealed. Scanning electron microscopy (SEM) confirmed [...] Read more.
In this study, the enhancement mechanism of the nano-dispersion of stearic acid-modified montmorillonite (SMMT) induced by carbon nanotubes (CNTs) in ethylene-butene terpolymer (EBT) was comprehensively investigated, and the regulation effect of composite fillers on EBT properties was revealed. Scanning electron microscopy (SEM) confirmed that SMMT achieved homogeneous nanoscale dispersion after CNT addition, and the size of aggregates was greatly reduced. Four-cycle strain-scanning analysis revealed a 200% increase in rubber–filler (R-F) interaction strength due to CNT incorporation. At the optimal CNT/SMMT ratio of 1:5, the EBT composites exhibited a 40.4% increase in Young’s modulus, 71.4% enhancement in tensile strength, and maintained 250% elongation at break, effectively addressing the strength–toughness trade-off of traditional rigid fillers. Thermogravimetric analysis (TGA) showed near 20 °C elevation in EBT composites’ maximum decomposition temperature, while water contact angle measurements indicated a hydrophobicity increase to 117.5° and water absorption rate below 0.2%. The quantitative improvement in thermal oxidation stability and hydrophobic barrier performance was achieved simultaneously. Full article
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