Search Results (326)

Deep eutectic solvents (DES) have emerged as a versatile and sustainable medium for the green synthesis of nanomaterials, offering a viable alternative to conventional organic solvents and ionic liquids. Nanomaterials can be synthesised in DESs via multiple routes, including chemical reduction, solvothermal, and electrochemical methods. Among the different pathways, this review focuses on the electrochemical synthesis of nanomaterials in DESs, as it offers several advantages: low cost, scalability for large-scale production, and low-temperature processing. The size, shape, and morphology (e.g., nanoparticles, nanoflowers, nanowires) of the resulting nanostructures can be tuned by adjusting the concentration of the electroactive species, the applied potential, the current density, mechanical agitation, and the electrolyte temperature. The use of DES as an electrolytic medium represents an environmentally friendly alternative. From an electrochemical perspective, it exhibits high electrochemical stability, good solubility for a wide range of precursors, and a broad electrochemical window. Furthermore, their low surface tensions promote high nucleation rates, and their high ionic strengths induce structural effects such as templating, capping and stabilisation, that play a crucial role in controlling particle morphology, size distribution and aggregation. Despite significant progress, key challenges persist, including incomplete mechanistic understanding, limited recyclability, and difficulties in scaling up synthesis while maintaining structural precision. This review highlights recent advances in the development of metal, alloy, oxide, and carbon-based composite nanomaterials obtained by electrochemical routes from DESs, along with their applications. Full article

System time delays and nonlinear unmodeled dynamics severely constrain the control performance of the Active Suspension Electro-Hydraulic Servo Actuator (ASEHSA). To tackle these challenges, this paper presents a Dynamic Error Differentiation-based Model-Free Adaptive Control (DE-MFAC) strategy integrated with an Improved Particle Swarm Optimization (IPSO) algorithm. Established under the Model-Free Adaptive Control (MFAC) framework, the DE-MFAC integrates a dynamic error differentiation mechanism and an implicit expression of time delays, thus removing the dependence on a precise system model. The traditional PSO algorithm is improved by incorporating an inertia weight adjustment strategy and a boundary reflection wall strategy, which effectively mitigates the issues of local optima and boundary stagnation. In AMESim 2021, a 1/4 vehicle active suspension electro-hydraulic actuation system model is constructed. To ensure an impartial evaluation of controller performance, the IPSO algorithm is employed to optimize the parameters of the PID, MFAC, and DE-MFAC controllers, respectively. Co-simulations with Simulink 2023b are conducted under two time delay scenarios using a composite square-sine wave signal as the reference. The results indicate that all three IPSO-optimized controllers realize effective position tracking. Among them, the DE-MFAC controller exhibits the optimal performance, demonstrating remarkable advantages in reducing tracking errors and balancing settling time with overshoot. These findings verify the effectiveness of the proposed control strategy, time delay compensation mechanism, and optimization algorithm. Future research will involve validation on a physical ASEHSA platform, further exploration of the method’s applicability and robustness under diverse operating conditions, and extension to other industrial systems with similar nonlinear time delay features. Full article

A water-soluble hydroxypropyl cellulose (HPC) polymer matrix has been filled with different weight percentages (wt.%) of multiwalled carbon nanotubes (MWCNTs), fullerenes C₆₀, fullerenols C₆₀(OH)_24, and their combinations. We study the potential of the 0D nanoparticles for improving electrical properties of the conductive MWCNT network in a biocompatible matrix. Physicochemical effects of fillers content, both individually and in combinations (MWCNTs/C₆₀ and MWCNTs/C₆₀(OH)₂₄), for these composite systems, have been investigated. The performed SAXS analysis shows improved nanofiller dispersion for films with two fillers. The electrical percolation threshold (P_c) in MWCNTs composites occurs at ≈1.0 wt.%. A synergistic effect for binary filler composites on the electrical conductivity has been evaluated by keeping a constant amount of 0.5 wt.% MWCNTs (σ ≈ 3 × 10⁻⁹ S·m⁻¹) and increasing the amount of C₆₀ or C₆₀(OH)₂₄. A large increase in the electrical conductivity is obtained for the bifiller composites with 0.5 wt.% MWCNTs and 1.5 wt.% of C₆₀(OH)₂₄, reaching σ ≈ 0.008 S·m⁻¹. Further, the sensing properties of 4.0/1.0 MWCNT/C₆₀ nanocomposites were demonstrated by measuring both piezoresistive (PR) and thermoresistive (TR) responses. The combination of semiconductive fullerene/fullerenols combined with MWCNTs allows obtaining more homogeneous composites in comparison to single MWCNTs composites and also gives possibilities for tuning the electrical conductivity of the system. Overall, it is demonstrated that the use of bifillers with a water soluble biopolymeric matrix allows the development of eco-friendly high-performance electroactive materials for sustainable digitalization. Full article

In this study, anodic oxidation (AO) was evaluated using Ti/IrO₂–SnO₂–Sb₂O₅ electrodes in chloride, sulfate, and mixed electrolytes, along with electro-Fenton (EF) and photoelectro-Fenton (PEF) at pH 3.0, for the degradation of alachlor and isoproturon, each 50 mg L⁻¹. Active chlorine species were monitored using UV–Vis, while the removal of both herbicides was quantified using High Performance Liquid Chromatography (HPLC), along with the reduction in Total Organic Carbon (TOC), mineralization current efficiency (MCE), and specific energy per TOC removed (EC_TOC). The results show that electrolyte composition influences AO more than current density. In a chloride medium, isoproturon was eliminated within minutes, whereas alachlor required mixed electrolytes of Cl⁻/SO₄²⁻, allowing simultaneous combination of HClO/ClO⁻, ^●OH, and S₂O₈²⁻/SO₄^●−, or coupling with EF. An optimal current density of ~30 mA cm⁻² limited voltage rise and radical scavenging. EF introduced measurable mineralization (15% TOC), whereas PEF achieved rapid alachlor reduction and TOC reductions of up to 76% at low Fe²⁺. Overall, sequential AO followed by PEF maximized mineralization per unit of energy, and the mixed electrolytes provided a controllable pathway to scale up oxidant speciation generation. Full article

Artificial muscles translate the biological principles of motion into soft, adaptive, and multifunctional actuation. This review accordingly highlights research into natural actuation strategies, such as skeletal muscles, muscular hydrostats, spider silk, and plant turgor systems, to reveal the principles underlying energy conversion and deformation control. Building on these insights, polymer-based artificial muscles based on these principles, including pneumatic muscles, dielectric elastomers, and ionic electroactive systems, are described and their capabilities for efficient contraction, bending, and twisting with tunable stiffness and responsiveness are summarized. Furthermore, the abilities of carbon nanotube composites and twisted yarns to amplify nanoscale dimensional changes through hierarchical helical architectures and achieve power and work densities comparable to those of natural muscle are discussed. Finally, the integration of these actuators into soft robotic systems is explored through biomimetic locomotion and manipulation systems ranging from jellyfish-inspired swimmers to octopus-like grippers, gecko-adhesive manipulators, and beetle-inspired flapping wings. Despite rapid progress in the development of artificial muscles, challenges remain in achieving long-term durability, energy efficiency, integrated sensing, and closed-loop control. Therefore, future research should focus on developing intelligent muscular systems that combine actuation, perception, and self-healing to advance progress toward realizing autonomous, lifelike machines that embody the organizational principles of living systems. Full article

The commercialization of direct urea fuel cells (DUFCs) is hampered by the scarcity of low-cost, high-performance electrocatalysts for the urea oxidation reaction (UOR), while water treatment processes generate spent adsorbents as a secondary waste. This study presents a circular economy solution by transforming a waste product—spent progesterone-loaded Reishi mushroom biosorbents—into high-performance anodes for DUFCs. We demonstrate that the thermal conversion of Ganoderma lucidum into biochar (Biochar/RM), followed by its “activation” through progesterone (PG) adsorption, creates a superior electrocatalytic composite (Biochar/RM/PG). Electrochemical evaluation revealed that this spent adsorbent delivers an exceptional UOR activity, achieving a peak current density of 225.52 mA cm⁻², which is 79% higher than its pristine counterpart. This enhancement is driven by a unique synergy: the biochar provides a conductive, porous framework, while the thermally transformed PG acts as an in situ dopant, creating nitrogen-rich active sites and optimizing the surface architecture for urea electro-oxidation. The catalyst further demonstrated remarkable operational stability over 3600 s. This work establishes a pioneering “waste-to-wealth” strategy, simultaneously addressing the challenges of pharmaceutical wastewater management and the need for sustainable energy materials. Full article

Chitin-derived biomass carbon materials are promising supercapacitor electrode materials due to their wide availability, low cost, high specific surface area, and nitrogen doping capability. However, their practical application is limited by insufficient conductivity and cyclic stability, often requiring functional modification or integration with complementary materials. In this study, we present a novel strategy by incorporating copper sulfide (Cu₂S) into a chitin-based carbon matrix. Cu₂S, known for its high intrinsic conductivity, excellent electroactivity, and theoretical specific capacity (~335 mAh·g⁻¹), was uniformly doped into the three-dimensional carbon aerogel framework derived from chitin nanofibers (ChNF) through sol–gel, freeze-drying, and high-temperature carbonization processes. The resulting chitin-based carbon/Cu₂S composite aerogel (CChNF/Cu₂S) exhibited a hierarchical porous structure with Cu₂S nanoparticles (20–30 nm) uniformly distributed on the carbon fiber surface. Electrochemical tests demonstrated its excellent performance, achieving a specific capacitance of 852 F·g⁻¹ at 1 A·g⁻¹, highlighting the synergistic effects of the conductive Cu₂S and nitrogen-doped carbon framework for high-performance supercapacitor applications. Full article

Biocompatible electroactive hydrogels with bidirectional pH-responsive bending are important for the creation of biomedical actuators. This study developed chitosan/carboxymethylcellulose (CS/CMC) semi-interpenetrating networks (SIPNs) with different volume ratios, which were crosslinked with glutaraldehyde. The swelling and bending behaviors of SPINs were systematically characterized as a function of the pH of the solution and the magnitude of the applied electric field. The hydrogels exhibited pH-dependent bidirectional actuation, with the maximum swelling of 4.67–6.00 at pH ≈ 3.9 and minimum swelling of 1.58–2.53 at pH ≈ 5.7. The SPINs with CS/CMC = 1:1 composition achieved the highest bending angle of 77° at pH ≈ 5.7, while cathodic bending up to an angle of −13.7° was observed in basic conditions. The electromechanical response was significantly enhanced by decreasing the electrode distance and increasing the applied voltage. The observed correlation between the composition, swelling behavior, and bending performance was explained in terms of the electrostatic interactions between NH₃⁺ and COO⁻ groups present in the CS/CMC mixtures. These findings provided novel insight into the ongoing efforts for the development of non-toxic electroactive hydrogels with tailored electromechanical bending behavior necessary for use as artificial muscles and biomedical actuators. Full article

Ionic Polymer–Metal Composites (IPMCs) are promising electroactive polymers for artificial muscles, as their bending motion depends on the induced current—greater current leads to greater bending. While conventional IPMCs use cation exchange membranes, this study explores IPMCs containing both immobile positive and negative charges, resembling real muscle tissue. Considering that an IPMC consists of an ion-exchange membrane sandwiched between two thin metal coatings serving as electrodes, we found that (i) improving the contact between the metal coating (electrode) and the ion exchange membrane is an effective way to enhance current induction. Achieving tight electrode membrane contact can drastically increase the induced current by up to four orders of magnitude, and even samples that previously showed no current induction can exhibit measurable current after improvement. (ii) Doping with mobile ions is another well-known method of enhancing IPMC current. However, we found that simply introducing dopants into the IPMC body is not effective; the choice of dopant is crucial. In this work, we identified silver ions as effective dopants for enhancing current induction. Considering that real muscles consume oxygen for activation, we also attempted to supply oxygen to the IPMC surface. We confirmed that (iii) supplying oxygen to the IPMC surface is another effective means of enhancing current induction, which in turn resulted in a significant improvement in IPMC bending performance. Full article

To address the challenges of complex composition, high chemical oxygen demand (COD) content, and the difficulty of treating organic wastewater from brewery wastewater, as well as the limitations of traditional Fenton technology, including low catalytic activity and high material costs, this study proposes the use of biochemical sludge as a raw material. Coupled with iron salt activation and mechanical ball milling technology, a low-cost, high-performance iron-doped mesoporous nano-sludge biochar material is prepared. This material was employed as a particle electrode to construct a three-dimensional electro-Fenton system for the degradation of organic wastewater from sauce-flavor liquor brewing. The results demonstrate that the sludge-based biochar produced through this approach possesses a mesoporous structure, with an average particle size of 187 nm, a specific surface area of 386.28 m²/g, and an average pore size of 4.635 nm. Iron is present in the material as multivalent iron ions, which provide more electrochemical reaction sites. Utilizing response surface methodology, the optimized treatment process achieves a maximum COD degradation rate of 71.12%. Compared to the control sample, the average particle size decreases from 287 μm to 187 nm, the specific surface area increases from 44.89 m²/g to 386.28 m²/g, and the COD degradation rate improves by 61.1%. Preliminary investigations suggest that the iron valence cycle (Fe²⁺/Fe³⁺) and the mass transfer enhancement effect of the mesoporous nano-structure are keys to efficient degradation. The Fe-O-Si structure enhances material stability, with a degradation capacity retention rate of 88.74% after 30 cycles of use. When used as a particle electrode to construct a three-dimensional electro-Fenton system, this material demonstrates highly efficiency in organic matter degradation and shows promising potential for application in the treatment of organic wastewater from sauce-flavor liquor brewing. Full article

In recent years, one of the major problems facing humanity has been the contamination of the environment by various organic pollutants, with some of them exhibiting environmental persistence or pseudo-persistence. For this reason, it is necessary today, more than ever, to find new and effective methods for degrading these persistent pollutants. Transition metal selenides (TMSes) have emerged as a versatile and promising class of catalysts for the degradation of organic pollutants through various advanced oxidation processes (AOPs). The widespread use of these materials lies in the desirable characteristics they offer, such as unique electronic structures, narrow band gaps, high electrical conductivity, and multi-valent redox behavior. This review comprehensively examines recent progress in the design, synthesis, and application of these TMSes—including both single- and composite systems, such as TMSes/g-C₃N₄, TMSes/TiO₂, and heterojunctions. The catalytic performance of these systems is being highlighted, regarding the degradation of organic pollutants such as dyes, pharmaceuticals, antibiotics, personal care products, etc. Further analysis of the mechanistic insights, structure–activity relationships, and operational parameter effects are critically discussed. Emerging trends, such as hybrid AOPs combining photocatalysis with PMS or electro-activation, and the challenges of stability, scalability, and real wastewater applicability are explored in depth. Finally, future directions emphasize the integration of multifunctional activation methods for the degradation of organic pollutants. This review aims to provide a comprehensive analysis and pave the way for the utilization of TMSe catalysts in sustainable and efficient wastewater remediation technologies. Full article

Plastic waste and industrial residues like steel slag pose significant environmental challenges, with limited recycling solutions. This study investigates a sustainable approach by repurposing waste polystyrene and steel slag into composite membranes via electrospinning for membrane distillation applications. Steel slag incorporation enhanced membrane porosity, hydrophobicity, and thermal stability, with process optimization performed through response surface methodology by varying slag content (0–10 wt%), voltage (15–30 kV), and feed rate (0.18–10 mL·h⁻¹). Optimized membranes achieved a reduced fiber diameter (1.172 µm), high porosity (82.3%), and superior hydrophobicity (contact angle 102.2°). Mechanical performance improved with a 12% increase in tensile strength and a threefold rise in liquid entry pressure over pure polystyrene membranes, indicating greater durability and wetting resistance. In direct contact membrane distillation, water flux improved by 15% while maintaining salt rejection above 98%. Under photothermal membrane distillation, evaporation rates rose by 69% and solar-to-thermal conversion efficiency by 60% compared to standard PVDF membranes. These results demonstrate the feasibility of transforming waste materials into high-performance, durable membranes, offering a scalable and eco-friendly solution for sustainable desalination. Full article

Polycaprolactone (PCL) is widely utilized in biomedical applications such as tissue engineering and drug delivery; however, its limited bioactivity remains a key challenge. In this study, bioactive curcumin–polycaprolactone block copolymers (MCP) were synthesized via ring-opening polymerization of ε-caprolactone and maleic anhydride modified curcumin. The resulting MCP was characterized using FTIR, ¹H NMR, UV–Vis spectroscopy, and differential scanning calorimetry (DSC). It demonstrated enhanced antioxidant activity, UV-blocking capacity, and electro spinnability compared to PCL. Electrospun MCP films exhibited improved biocompatibility and promoted fibroblast migration. Furthermore, composite films incorporating MCP into a PVA matrix with and without copper or iron were evaluated for in vivo toxicity and antimicrobial activity. These formulations showed no systemic or contact toxicity in the Galleria mellonella model, confirming their biocompatibility. Films containing copper or iron exhibited selective anti-Pseudomonas aeruginosa activity and low but reproducible antioxidant capacity. This study highlights the multifunctionality and biomedical potential of MCP and its composites as tunable platforms for regenerative and antimicrobial applications. Full article

We report the observation of a linear electro-optic (EO) response in CsPbX₃ (X = Cl, Br, I) perovskite nanocrystal (NC) films fabricated via electrophoretic deposition (EPD). Under an alternating electric field, the EPD films exhibit clear linear EO modulation of transmitted light intensity, indicating the formation of an anisotropic medium through field-induced NC alignment. In contrast, spin-coated NC films show no measurable linear EO response, underscoring the critical role of structural anisotropy introduced by EPD. All EPD samples exhibit a decreasing EO response with increasing modulation frequency, consistent with the involvement of slow ion migration dynamics. The halide composition influences EO behavior, with Br/Cl mixed-composition films maintaining the highest EO response at elevated frequencies, and Br-based NCs showing stronger EO signals than their Cl counterparts, while Bi-doped CsPbBr₃ films exhibit quenched photoluminescence yet retain a measurable but weaker EO response, underscoring the trade-off between defect-induced nonradiative recombination and EO activity. These results highlight the potential of EPD-assembled perovskite NCs for reconfigurable EO applications by tailoring composition and microstructure. Full article

This study investigates the influence of electrical actuation parameters on the performance of a morphing composite aerodynamic profile actuated by Shape Memory Alloy (SMA) wires. A fully coupled electro-thermo-mechanical finite element model has been developed to simulate the transient response of NiTi SMA, capturing the nonlinear interplay between temperature evolution, phase transformation, and mechanical deformation under Joule heating. The model incorporates phase-dependent material properties, heat effects, and geometric constraints, enabling accurate prediction of actuation dynamics. To validate the model, a morphing spoiler prototype has been fabricated using high-performance additive manufacturing with a carbon fibre-reinforced polymer. The SMA wires have been pretensioned and electrically actuated at different current levels (3 A and 6 A), and the resulting deformation has been recorded through video analysis with embedded timers. Experimental measurements confirmed the model’s ability to predict both actuation time and displacement, with maximum deflections of 33 mm and 40 mm corresponding to different current inputs. This integrated approach demonstrates an efficient and compact solution for active aerodynamic surfaces without the need for mechanical linkages, enabling future developments in adaptive structures for automotive and aerospace applications. Full article