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Search Results (923)

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Keywords = electrochemical active surface areas

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18 pages, 1807 KiB  
Article
Influence of Pyrolysis Temperature on the Properties and Electrochemical Performance of Cedar Wood-Derived Biochar for Supercapacitor Electrodes
by Layal Abdallah, Chantal Gondran, Virginie Monnier, Christian Vollaire and Naoufel Haddour
Bioengineering 2025, 12(8), 841; https://doi.org/10.3390/bioengineering12080841 (registering DOI) - 4 Aug 2025
Abstract
This study examines the effect of temperature during pyrolysis on the capacity of cedar wood-derived biochar to be employed as a sustainable electrode material for supercapacitors. Cedar wood-derived biochars were produced at different temperatures of 800 °C, 900 °C, 1000 °C and 1100 [...] Read more.
This study examines the effect of temperature during pyrolysis on the capacity of cedar wood-derived biochar to be employed as a sustainable electrode material for supercapacitors. Cedar wood-derived biochars were produced at different temperatures of 800 °C, 900 °C, 1000 °C and 1100 °C and fully characterized in terms of their structural, physicochemical and electrochemical properties, including specific surface area, hydrophobicity, electrical conductivity, and surface functional groups. The results indicated that the cedar wood biochar obtained through pyrolysis at 900 °C (BC900) provided optimal electrical conductivity, hydrophobicity, and porosity characteristics relative to the other cedar wood biochars produced by pyrolysis at 800 °C to 1100 °C. Specifically, when compared to commercial activated carbon (AC), BC900 provided half the specific capacitance at a current density of 1 A g−1 and indicated that there is more potential for improvement with further activation and doping. The influence of the binder (either polyvinylidene fluoride (PVDF) or chitosan) in combination with conductive carbon black (CB) was also examined. Electrodes fabricated with PVDF binder showed higher specific capacitance, while biochar electrodes made from CB and chitosan (BC900/CB/chitosan) showed better electrical conductivity, wettability, and good electrochemical stability with >95% capacity retention even after 10,000 cycles. Full article
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26 pages, 5007 KiB  
Article
Copper-Enhanced NiMo/TiO2 Catalysts for Bifunctional Green Hydrogen Production and Pharmaceutical Pollutant Removal
by Nicolás Alejandro Sacco, Fernanda Albana Marchesini, Ilaria Gamba and Gonzalo García
Catalysts 2025, 15(8), 737; https://doi.org/10.3390/catal15080737 - 1 Aug 2025
Viewed by 175
Abstract
This study presents the development of Cu-doped NiMo/TiO2 photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at [...] Read more.
This study presents the development of Cu-doped NiMo/TiO2 photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at 400 °C and 900 °C to investigate structural transformations and catalytic performance. Comprehensive characterization (XRD, BET, SEM, XPS) revealed phase transitions, enhanced crystallinity, and redistribution of redox states upon Cu incorporation, particularly the formation of NiTiO3 and an increase in oxygen vacancies. Crystallite sizes for anatase, rutile, and brookite ranged from 21 to 47 nm at NiMoCu400, while NiMoCu900 exhibited only the rutile phase with 55 nm crystallites. BET analysis showed a surface area of 44.4 m2·g−1 for NiMoCu400, and electrochemical measurements confirmed its higher electrochemically active surface area (ECSA, 2.4 cm2), indicating enhanced surface accessibility. In contrast, NiMoCu900 exhibited a much lower BET surface area (1.4 m2·g−1) and ECSA (1.4 cm2), consistent with its inferior photoelectrocatalytic performance. Compared to previously reported binary NiMo/TiO2 systems, the ternary NiMoCu/TiO2 catalysts demonstrated significantly improved hydrogen production activity and more efficient photoelectrochemical degradation of paracetamol. Specifically, NiMoCu400 showed an anodic peak current of 0.24 mA·cm−2 for paracetamol oxidation, representing a 60% increase over NiMo400 and a cathodic current of −0.46 mA·cm−2 at −0.1 V vs. RHE under illumination, nearly six times higher than the undoped counterpart (–0.08 mA·cm−2). Mott–Schottky analysis further revealed that NiMoCu400 retained n-type behavior, while NiMoCu900 exhibited an unusual inversion to p-type, likely due to Cu migration and rutile-phase-induced realignment of donor states. Despite its higher photosensitivity, NiMoCu900 showed negligible photocurrent, confirming that structural preservation and surface redox activity are critical for photoelectrochemical performance. This work provides mechanistic insight into Cu-mediated photoelectrocatalysis and identifies NiMoCu/TiO2 as a promising bifunctional platform for integrated solar-driven water treatment and sustainable hydrogen production. Full article
(This article belongs to the Section Electrocatalysis)
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16 pages, 4770 KiB  
Article
Developing a CeS2/ZnS Quantum Dot Composite Nanomaterial as a High-Performance Cathode Material for Supercapacitor
by Shan-Diao Xu, Li-Cheng Wu, Muhammad Adil, Lin-Feng Sheng, Zi-Yue Zhao, Kui Xu and Xin Chen
Batteries 2025, 11(8), 289; https://doi.org/10.3390/batteries11080289 - 1 Aug 2025
Viewed by 183
Abstract
To develop high-performance electrode materials for supercapacitors, in this paper, a heterostructured composite material of cerium sulfide and zinc sulfide quantum dots (CeS2/ZnS QD) was successfully prepared by hydrothermal method. Characterization through scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission [...] Read more.
To develop high-performance electrode materials for supercapacitors, in this paper, a heterostructured composite material of cerium sulfide and zinc sulfide quantum dots (CeS2/ZnS QD) was successfully prepared by hydrothermal method. Characterization through scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) showed that ZnS QD nanoparticles were uniformly composited with CeS2, effectively increasing the active sites surface area and shortening the ion diffusion path. Electrochemical tests show that the specific capacitance of this composite material reaches 2054 F/g at a current density of 1 A/g (specific capacity of about 256 mAh/g), significantly outperforming the specific capacitance of pure CeS2 787 F/g at 1 A/g (specific capacity 98 mAh/g). The asymmetric supercapacitor (ASC) assembled with CeS2/ZnS QD and activated carbon (AC) retained 84% capacitance after 10,000 charge–discharge cycles. Benefited from the synergistic effect between CeS2 and ZnS QDs, the significantly improved electrochemical performance of the composite material suggests a promising strategy for designing rare-earth and QD-based advanced energy storage materials. Full article
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13 pages, 3341 KiB  
Article
Regulation of Electrochemical Activity via Controlled Integration of NiS2 over Co3O4 Nanomaterials for Hydrogen Evolution Reaction
by Mrunal Bhosale, Rutuja U. Amate, Pritam J. Morankar and Chan-Wook Jeon
Coatings 2025, 15(8), 887; https://doi.org/10.3390/coatings15080887 - 30 Jul 2025
Viewed by 194
Abstract
Electrochemical water splitting represents a sustainable approach for hydrogen production, yet efficient hydrogen evolution reaction (HER) catalysts operating in alkaline environments remain critically needed. Herein, we report the fabrication of Co3O4–NiS2 nanocomposites synthesized through a facile coprecipitation and [...] Read more.
Electrochemical water splitting represents a sustainable approach for hydrogen production, yet efficient hydrogen evolution reaction (HER) catalysts operating in alkaline environments remain critically needed. Herein, we report the fabrication of Co3O4–NiS2 nanocomposites synthesized through a facile coprecipitation and subsequent thermal treatment method. Detailed characterization via physicochemical techniques confirmed the successful formation of a hybrid Co3O4–NiS2 heterostructure with tunable compositional and morphological characteristics. Among the synthesized catalysts (Co–Ni–1, Co–Ni–2, and Co–Ni–3), the Co–Ni–2 sample demonstrated optimal structural integration, displaying interconnected nanosheet morphologies and balanced elemental distribution. Remarkably, Co–Ni–2 achieved exceptional HER performance in 1 M KOH electrolyte, requiring an ultralow overpotential of only 84 mV at 10 mA cm−2 and exhibiting a favorable Tafel slope of 67.5 mV dec−1. Electrochemical impedance spectroscopy and electrochemical surface area measurements further substantiated the superior electrocatalytic kinetics, rapid charge transport, and abundant active site accessibility in the optimized Co–Ni–2 composite. Additionally, Co–Ni–2 demonstrated outstanding durability with negligible activity decay over 5000 cycles. This study not only highlights the strategic synthesis of Co3O4–NiS2 nanostructures but also provides valuable insights for designing advanced, stable, and efficient non-noble electrocatalysts for sustainable hydrogen generation. Full article
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16 pages, 4296 KiB  
Article
Enhanced Photocathodic Protection Performance of TiO2/NiCo2S4 Composites for 304 Stainless Steel
by Honggang Liu, Hong Li, Xuan Zhang, Baizhao Xing, Zhuangzhuang Sun and Yanhui Li
Coatings 2025, 15(8), 874; https://doi.org/10.3390/coatings15080874 - 25 Jul 2025
Viewed by 312
Abstract
To address the corrosion of 304 stainless steel in marine environments, TiO2/NiCo2S4 composite photoanodes were fabricated via anodic oxidation and hydrothermal methods. X-ray diffraction, scanning electron microscope, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy analyses indicated the growth [...] Read more.
To address the corrosion of 304 stainless steel in marine environments, TiO2/NiCo2S4 composite photoanodes were fabricated via anodic oxidation and hydrothermal methods. X-ray diffraction, scanning electron microscope, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy analyses indicated the growth of hexagonal NiCo2S4 particles on anatase TiO2 nanotube arrays, forming a type-II heterojunction. Spectroscopy of ultraviolet-visible diffuse reflectance absorption showed that NiCo2S4 extended TiO2’s light absorption into the visible region. Electrochemical tests revealed that under visible light, the composite photoanode decreased the corrosion potential of 304ss to −0.7 V vs. SCE and reduced charge transfer resistance by 20% compared to pure TiO2. The enhanced performance stemmed from efficient electron-hole separation and transport enabled by the type-II heterojunction. Cyclic voltammetry tests indicated the composite’s electrochemical active surface area increased 1.8-fold, demonstrating superior catalytic activity. In conclusion, the TiO2/NiCo2S4 composite photoanode offers an effective approach for marine corrosion protection of 304ss. Full article
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63 pages, 4971 KiB  
Review
Electrochemical Nanosensors Applied to the Assay of Some Food Components—A Review
by Aurelia Magdalena Pisoschi, Florin Iordache, Loredana Stanca, Petronela Mihaela Rosu, Nicoleta Ciocirlie, Ovidiu Ionut Geicu, Liviu Bilteanu and Andreea Iren Serban
Chemosensors 2025, 13(8), 272; https://doi.org/10.3390/chemosensors13080272 - 23 Jul 2025
Viewed by 573
Abstract
Nanomaterials’ special features enable their extensive application in chemical and biochemical nanosensors for food assays; food packaging; environmental, medicinal, and pharmaceutical applications; and photoelectronics. The analytical strategies based on novel nanomaterials have proved their pivotal role and increasing interest in the assay of [...] Read more.
Nanomaterials’ special features enable their extensive application in chemical and biochemical nanosensors for food assays; food packaging; environmental, medicinal, and pharmaceutical applications; and photoelectronics. The analytical strategies based on novel nanomaterials have proved their pivotal role and increasing interest in the assay of key food components. The choice of transducer is pivotal for promoting the performance of electrochemical sensors. Electrochemical nano-transducers provide a large active surface area, enabling improved sensitivity, specificity, fast assay, precision, accuracy, and reproducibility, over the analytical range of interest, when compared to traditional sensors. Synthetic routes encompass physical techniques in general based on top–down approaches, chemical methods mainly relying on bottom–up approaches, or green technologies. Hybrid techniques such as electrochemical pathways or photochemical reduction are also applied. Electrochemical nanocomposite sensors relying on conducting polymers are amenable to performance improvement, achieved by integrating redox mediators, conductive hydrogels, and molecular imprinting polymers. Carbon-based or metal-based nanoparticles are used in combination with ionic liquids, enhancing conductivity and electron transfer. The composites may be prepared using a plethora of combinations of carbon-based, metal-based, or organic-based nanomaterials, promoting a high electrocatalytic response, and can accommodate biorecognition elements for increased specificity. Nanomaterials can function as pivotal components in electrochemical (bio)sensors applied to food assays, aiming at the analysis of bioactives, nutrients, food additives, and contaminants. Given the broad range of transducer types, detection modes, and targeted analytes, it is important to discuss the analytical performance and applicability of such nanosensors. Full article
(This article belongs to the Special Issue Electrochemical Sensor for Food Analysis)
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14 pages, 4216 KiB  
Article
Redox-Active Anthraquinone-1-Sulfonic Acid Sodium Salt-Loaded Polyaniline for Dual-Functional Electrochromic Supercapacitors
by Yi Wang, Enkai Lin, Ze Wang, Tong Feng and An Xie
Gels 2025, 11(8), 568; https://doi.org/10.3390/gels11080568 - 23 Jul 2025
Viewed by 213
Abstract
Electrochromic (EC) devices are gaining increasing attention for next-generation smart windows and low-power displays due to their reversible color modulation, low operating voltage, and flexible form factors. Recently, electrochromic energy storage devices (EESDs) have emerged as a promising class of multifunctional systems, enabling [...] Read more.
Electrochromic (EC) devices are gaining increasing attention for next-generation smart windows and low-power displays due to their reversible color modulation, low operating voltage, and flexible form factors. Recently, electrochromic energy storage devices (EESDs) have emerged as a promising class of multifunctional systems, enabling simultaneous energy storage and real-time visual monitoring. In this study, we report a flexible dual-functional EESD constructed using polyaniline (PANI) films doped with anthraquinone-1-sulfonic acid sodium salt (AQS), coupled with a redox-active PVA-based gel electrolyte also incorporating AQS. The incorporation of AQS into both the polymer matrix and the gel electrolyte introduces synergistic redox activity, facilitating bidirectional Faradaic reactions at the film–electrolyte interface and within the bulk gel phase. The resulting vertically aligned PANI-AQS nanoneedle films provide high surface area and efficient ion pathways, while the AQS-doped gel electrolyte contributes to enhanced ionic conductivity and electrochemical stability. The device exhibits rapid and reversible color switching from light green to deep black (within 2 s), along with a high areal capacitance of 194.2 mF·cm−2 at 1 mA·cm−2 and 72.1% capacitance retention over 5000 cycles—representing a 31.5% improvement over undoped systems. These results highlight the critical role of redox-functionalized gel electrolytes in enhancing both the energy storage and optical performance of EESDs, offering a scalable strategy for multifunctional, gel-based electrochemical systems in wearable and smart electronics. Full article
(This article belongs to the Special Issue Smart Gels for Sensing Devices and Flexible Electronics)
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14 pages, 3096 KiB  
Article
Photoelectrochemical CO2 Reduction Measurements of a BiOI Coating Deposited onto a Non-Conductive Glass Support as a Platform for Environmental Remediation
by J. Manuel Mora-Hernandez and A. Hernández-Ramírez
Processes 2025, 13(7), 2292; https://doi.org/10.3390/pr13072292 - 18 Jul 2025
Viewed by 490
Abstract
Aiming to contribute to environmental remediation strategies, this work proposes a novel fabrication of photoelectrocatalytic electrodes containing a BiOI coating deposited onto non-conductive glass (NCG) for CO2 conversion applications. When BiOI electrodes are not deposited onto fluorine-doped tin oxide (FTO) or indium [...] Read more.
Aiming to contribute to environmental remediation strategies, this work proposes a novel fabrication of photoelectrocatalytic electrodes containing a BiOI coating deposited onto non-conductive glass (NCG) for CO2 conversion applications. When BiOI electrodes are not deposited onto fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) conductive supports, the electrochemical measurements enable the registration of the (photo)electrochemical response for bare BiOI, thereby excluding remnant signals from the conductive supports and reporting an exclusive and proper photoelectrocatalytic BiOI response. A systematic procedure was carried out to improve the physicochemical properties of BiOI through a simple variation in the amount of reagents employed in a solvothermal synthesis, thus increasing the crystallite size and surface area of the resulting material (BiOI-X3-20wt.%). The tailored BiOI coating on a non-conductive support showed activity in performing CO2 photoelectroreduction under UV–Vis irradiation in aqueous media. Finally, the BiOI-X3-20wt.% sample was evaluated for photocatalytic CO2 conversion in gaseous media, producing CO as the primary reaction product. This study confirms that BiOI is a suitable and easily synthesized material, with potential applications for CO2 capture and conversion when employed as a photoactive coating for environmental remediation. Full article
(This article belongs to the Special Issue Advanced Application of Photoelectrocatalysis for Energy Conversion)
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14 pages, 3397 KiB  
Article
The Capacitive Property Enhancement of CoFeP-Ni(OH)2/Nickel Foam Electrodes via an Interfacial Integration Strategy for Asymmetric Supercapacitors
by Meiying Cui, Meiying Pei and Seok Kim
Molecules 2025, 30(14), 2986; https://doi.org/10.3390/molecules30142986 - 16 Jul 2025
Viewed by 310
Abstract
We report the fabrication of CoFeP-Ni(OH)2/nickel foam (NF) composite electrodes via a two-step strategy involving the hydrothermal synthesis of Ni(OH)2 on nickel foam followed by the electrochemical deposition of CoFeP. The integration of the Ni(OH)2 interlayer not only provides [...] Read more.
We report the fabrication of CoFeP-Ni(OH)2/nickel foam (NF) composite electrodes via a two-step strategy involving the hydrothermal synthesis of Ni(OH)2 on nickel foam followed by the electrochemical deposition of CoFeP. The integration of the Ni(OH)2 interlayer not only provides a structurally robust interface but also facilitates synergistic redox activity, thereby significantly boosting the pseudocapacitive behavior of the electrode. Comparative analysis with bare CoFeP/NF reveals that the presence of the Ni(OH)2 layer contributes to enhanced charge transfer efficiency and an increased electroactive surface area. Among the samples prepared under varying deposition cycles, the optimized CoFeP-Ni(OH)2/NF electrode exhibits a high areal capacitance of 4244 mF cm−2 at 2 mA cm−2. Furthermore, an asymmetric supercapacitor device assembled with CoFeP-Ni(OH)2/NF as the positive electrode and activated carbon as the negative electrode delivers a maximum energy density of 0.19 mWh cm−2 at a power density of 0.37 mW cm−2 and excellent cycling stability, retaining 72% of its initial capacitance after 5000 cycles at a high current density of 8 mA cm−2. Full article
(This article belongs to the Special Issue Inorganic Chemistry in Asia)
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20 pages, 1303 KiB  
Review
The Role of Nanomaterials in the Wearable Electrochemical Glucose Biosensors for Diabetes Management
by Tahereh Jamshidnejad-Tosaramandani, Soheila Kashanian, Kobra Omidfar and Helgi B. Schiöth
Biosensors 2025, 15(7), 451; https://doi.org/10.3390/bios15070451 - 14 Jul 2025
Viewed by 453
Abstract
The increasing prevalence of diabetes mellitus necessitates the development of advanced glucose-monitoring systems that are non-invasive, reliable, and capable of real-time analysis. Wearable electrochemical biosensors have emerged as promising tools for continuous glucose monitoring (CGM), particularly through sweat-based platforms. This review highlights recent [...] Read more.
The increasing prevalence of diabetes mellitus necessitates the development of advanced glucose-monitoring systems that are non-invasive, reliable, and capable of real-time analysis. Wearable electrochemical biosensors have emerged as promising tools for continuous glucose monitoring (CGM), particularly through sweat-based platforms. This review highlights recent advancements in enzymatic and non-enzymatic wearable biosensors, with a specific focus on the pivotal role of nanomaterials in enhancing sensor performance. In enzymatic sensors, nanomaterials serve as high-surface-area supports for glucose oxidase (GOx) immobilization and facilitate direct electron transfer (DET), thereby improving sensitivity, selectivity, and miniaturization. Meanwhile, non-enzymatic sensors leverage metal and metal oxide nanostructures as catalytic sites to mimic enzymatic activity, offering improved stability and durability. Both categories benefit from the integration of carbon-based materials, metal nanoparticles, conductive polymers, and hybrid composites, enabling the development of flexible, skin-compatible biosensing systems with wireless communication capabilities. The review critically evaluates sensor performance parameters, including sensitivity, limit of detection, and linear range. Finally, current limitations and future perspectives are discussed. These include the development of multifunctional sensors, closed-loop therapeutic systems, and strategies for enhancing the stability and cost-efficiency of biosensors for broader clinical adoption. Full article
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24 pages, 7332 KiB  
Article
High-Performance Natural Dye-Sensitized Solar Cells Employing a New Semiconductor: Gd2Ru2O7 Pyrochlore Oxide
by Assohoun F. Kraidy, Abé S. Yapi, Joseph K. Datte, Michel Voue, Mimoun El Marssi, Anthony Ferri and Yaovi Gagou
Condens. Matter 2025, 10(3), 38; https://doi.org/10.3390/condmat10030038 - 14 Jul 2025
Viewed by 623
Abstract
We investigated a novel natural dye-sensitized solar cell (DSSC) utilizing gadolinium ruthenate pyrochlore oxide Gd2Ru2O7 (GRO) as a photoanode and compared its performance to the TiO2-Gd2Ru2O7 (TGRO) combined-layer configuration. The films [...] Read more.
We investigated a novel natural dye-sensitized solar cell (DSSC) utilizing gadolinium ruthenate pyrochlore oxide Gd2Ru2O7 (GRO) as a photoanode and compared its performance to the TiO2-Gd2Ru2O7 (TGRO) combined-layer configuration. The films were fabricated using the spin-coating technique, resulting in spherical grains with an estimated mean diameter of 0.2 µm, as observed via scanning electron microscopy (SEM). This innovative photoactive gadolinium ruthenate pyrochlore oxide demonstrated strong absorption in the visible range and excellent dye adhesion after just one hour of exposure to natural dye. X-ray diffraction confirmed the presence of the pyrochlore phase, where Raman spectroscopy identified various vibration modes characteristic of the pyrochlore structure. Incorporating Gd2Ru2O7 as the photoanode significantly enhanced the overall efficiency of the DSSCs. The device configuration FTO/compact-layer/Gd2Ru2O7/Hibiscus-sabdariffa/electrolyte(I/I3)/Pt achieved a high efficiency of 9.65%, an open-circuit voltage (Voc) of approximately 3.82 V, and a current density of 4.35 mA/cm2 for an active surface area of 0.38 cm2. A mesoporous TiO2-based DSSC was fabricated under the same conditions for comparison. Using impedance spectroscopy and cyclic voltammetry measurements, we provided evidence of the mechanism of conductivity and the charge carrier’s contribution or defect contributions in the DSSC cells to explain the obtained Voc value. Through cyclic voltammetry measurements, we highlight the redox activities of hibiscus dye and electrolyte (I/I3), which confirmed electrochemical processes in addition to a photovoltaic response. The high and unusual obtained Voc value was also attributed to the presence in the photoanode of active dipoles, the layer thickness, dye concentration, and the nature of the electrolyte. Full article
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20 pages, 2436 KiB  
Article
Advanced Hybrid Nanocatalysts for Green Hydrogen: Carbon-Supported MoS2 and ReS2 as Noble Metal Alternatives
by Maria Jarząbek-Karnas, Zuzanna Bojarska, Patryk Klemczak, Łukasz Werner and Łukasz Makowski
Int. J. Mol. Sci. 2025, 26(14), 6640; https://doi.org/10.3390/ijms26146640 - 10 Jul 2025
Viewed by 509
Abstract
One of the key challenges in commercializing proton exchange membrane (PEM) electrolyzer technology is reducing the production costs while maintaining high efficiency and operational stability. Significant contributors to the overall cost of the device are the electrode catalysts with IrO2 and Pt/C. [...] Read more.
One of the key challenges in commercializing proton exchange membrane (PEM) electrolyzer technology is reducing the production costs while maintaining high efficiency and operational stability. Significant contributors to the overall cost of the device are the electrode catalysts with IrO2 and Pt/C. Due to the high cost and limited availability of noble metals, there is growing interest in developing alternative, low-cost catalytic materials. In recent years, two-dimensional transition metal dichalcogenides (2D TMDCs), such as molybdenum disulfide (MoS2) and rhenium disulfide (ReS2), have attracted considerable attention due to their promising electrochemical properties for hydrogen evolution reactions (HERs). These materials exhibit unique properties, such as a high surface area or catalytic activity localized at the edges of the layered structure, which can be further enhanced through defect engineering or phase modulation. To increase the catalytically active surface area, the investigated materials were deposited on a carbon-based support—Vulcan XC-72R—selected for its high electrical conductivity and large specific surface area. This study investigated the physicochemical and electrochemical properties of six catalyst samples with varying MoS2 and ReS2 to carbon support ratios. Among the composites analyzed, the best sample on MoS2 (containing the most carbon soot) and the best sample on ReS2 (containing the least carbon soot) were selected. These were then used as cathode catalysts in an experimental PEM electrolyzer setup. The results confirmed satisfactory catalytic activity of the tested materials, indicating their potential as alternatives to conventional noble metal-based catalysts and providing a foundation for further research in this area. Full article
(This article belongs to the Section Materials Science)
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28 pages, 4234 KiB  
Review
A Review on Laser-Induced Graphene-Based Electrocatalysts for the Oxygen Reduction Reaction in Electrochemical Energy Storage and Conversion
by Giulia Massaglia and Marzia Quaglio
Nanomaterials 2025, 15(14), 1070; https://doi.org/10.3390/nano15141070 - 10 Jul 2025
Viewed by 455
Abstract
The increasing demand for efficient and sustainable energy conversion technologies has driven extensive research into alternative electrocatalysts for the oxygen reduction reaction (ORR). Platinum-based catalysts, while highly efficient, suffer from high costs, scarcity, and long-term instability Laser-Induced Graphene (LIG) has recently attracted considerable [...] Read more.
The increasing demand for efficient and sustainable energy conversion technologies has driven extensive research into alternative electrocatalysts for the oxygen reduction reaction (ORR). Platinum-based catalysts, while highly efficient, suffer from high costs, scarcity, and long-term instability Laser-Induced Graphene (LIG) has recently attracted considerable interest as an effective metal-free electrocatalyst for oxygen reduction reaction (ORR), owing to its remarkable electrical conductivity, customizable surface functionalities, and multi-scale porous architecture. This review explores the synthesis strategies, physicochemical properties, and ORR catalytic performance of LIG. Additionally, this review offered a detailed overview regarding the effective pole of heteroatom doping (N, S, P, B) and functionalization techniques to enhance catalytic activity. Finally, we highlight the current challenges and future perspectives of LIG-based ORR catalysts for fuel cells and other electrochemical energy applications. Furthermore, laser-induced-graphene (LIG) has emerged as a highly attractive candidate for electrochemical energy conversion systems, due to its large specific surface area, tunable porosity, excellent electrical conductivity, and cost-effective fabrication process. This review discusses recent advancements in LIG synthesis, its structural and electrochemical properties, and its applications in supercapacitors, batteries, fuel cells, and electrocatalysis. Despite its advantages, challenges such as mechanical stability, electrochemical degradation, and large-scale production remain key areas for improvement. Additionally, this review explores future perspectives on optimizing LIG for next-generation energy storage and conversion technologies. Full article
(This article belongs to the Special Issue Nanomaterials Based (Bio) Electrochemical Energy and Storage Sytems)
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20 pages, 3918 KiB  
Article
Engineered Cu0.5Ni0.5Al2O4/GCN Spinel Nanostructures for Dual-Functional Energy Storage and Electrocatalytic Water Splitting
by Abdus Sami, Sohail Ahmad, Ai-Dang Shan, Sijie Zhang, Liming Fu, Saima Farooq, Salam K. Al-Dawery, Hamed N. Harharah, Ramzi H. Harharah and Gasim Hayder
Processes 2025, 13(7), 2200; https://doi.org/10.3390/pr13072200 - 9 Jul 2025
Viewed by 350
Abstract
The rapid growth in population and industrialization have significantly increased global energy demand, placing immense pressure on finite and environmentally harmful conventional fossil fuel-based energy sources. In this context, the development of hybrid electrocatalysts presents a crucial solution for energy conversion and storage, [...] Read more.
The rapid growth in population and industrialization have significantly increased global energy demand, placing immense pressure on finite and environmentally harmful conventional fossil fuel-based energy sources. In this context, the development of hybrid electrocatalysts presents a crucial solution for energy conversion and storage, addressing environmental challenges while meeting rising energy needs. In this study, the fabrication of a novel bifunctional catalyst, copper nickel aluminum spinel (Cu0.5Ni0.5Al2O4) supported on graphitic carbon nitride (GCN), using a solid-state synthesis process is reported. Because of its effective interface design and spinel cubic structure, the Cu0.5Ni0.5Al2O4/GCN nanocomposite, as synthesized, performs exceptionally well in electrochemical energy conversion, such as the oxygen evolution reaction (OER), the hydrogen evolution reaction (HER), and energy storage. In particular, compared to noble metals, Pt/C- and IrO2-based water-splitting cells require higher voltages (1.70 V), while for the Cu0.5Ni0.5Al2O4/GCN nanocomposite, a voltage of 1.49 V is sufficient to generate a current density of 10 mA cm−2 in an alkaline solution. When used as supercapacitor electrode materials, Cu0.5Ni0.5Al2O4/GCN nanocomposites show a specific capacitance of 1290 F g−1 at a current density of 1 A g−1 and maintain a specific capacitance of 609 F g−1 even at a higher current density of 5 A g−1, suggesting exceptional rate performance and charge storage capacity. The electrode’s exceptional capacitive properties were further confirmed through the determination of the roughness factor (Rf), which represents surface heterogeneity and active area enhancement, with a value of 345.5. These distinctive characteristics render the Cu0.5Ni0.5Al2O4/GCN composite a compelling alternative to fossil fuels in the ongoing quest for a viable replacement. Undoubtedly, the creation of the Cu0.5Ni0.5Al2O4/GCN composite represents a significant breakthrough in addressing the energy crisis and environmental concerns. Owing to its unique composition and electrocatalytic characteristics, it is considered a feasible choice in the pursuit of ecologically sustainable alternatives to fossil fuels. Full article
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15 pages, 2102 KiB  
Article
MXene-Based Flexible Paper Chip for Glucose Detection in Sweat in Low-Temperature Environments
by Yandong Yang, Yajun Zhu, Yifei Wu, Fan Chang, Xu Zhu, Xinyue Zhang, Ning Ma, Yushu Wang and Alaa S. Abd-El-Aziz
Sensors 2025, 25(14), 4273; https://doi.org/10.3390/s25144273 - 9 Jul 2025
Viewed by 408
Abstract
In enzymatic reaction glucose detection chips, the enzyme can easily dislodge from the electrode, which harms both the chip and test stability. Additionally, enzyme activity significantly decreases at low temperatures. Consequently, immobilizing the enzyme at the appropriate substrate and ambient temperature is a [...] Read more.
In enzymatic reaction glucose detection chips, the enzyme can easily dislodge from the electrode, which harms both the chip and test stability. Additionally, enzyme activity significantly decreases at low temperatures. Consequently, immobilizing the enzyme at the appropriate substrate and ambient temperature is a critical step for improving the chip. To address this issue, an electrochemical detection chip was modified using the nanomaterial MXene, known for its large specific surface area, excellent adsorption, good dispersion, and high conductivity. Meanwhile, AgNO3 solution was added to the Ti3C2Tx MXene nanosheet solution, and the AgNP@MXene material was prepared by heating in a water bath. This process further enhances photothermal conversion efficiency due to the localized surface plasmon resonance effect of silver nanoparticles and MXene. This MXene-based photothermally enhanced paper chip exhibits outstanding photothermal conversion performance and sensitive photoelectrochemical responsiveness, along with good cycling stability. Moreover, improved glucose detection sensitivity at low winter temperatures has been achieved, and the ambient temperature range of the paper chip has been expanded to 25–37 °C. Full article
(This article belongs to the Special Issue The Advanced Flexible Electronic Devices: 2nd Edition)
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