Search Results (165)

Developing bifunctional non-noble metal electrocatalysts with high activity, stability, and cost-effectiveness is essential for large-scale sustainable water splitting, yet remains challenging. Herein, 2P-FeCoNi-MOF was synthesized via hydrothermal reaction of FeCoNi-LDH followed by phosphidation. Its layered structure, integrated with 3D nickel foam, creates a hierarchical porous architecture that increases surface area and accelerates electron transport. Synergistic effects among Fe, Co, Ni in the trimetallic phosphides, together with an amorphous carbon layer, boost catalytic performance. Moreover, superhydrophilic and superaerophobic surfaces enhance mass transfer. In 1 M KOH, 2P-FeCoNi-MOF achieves low overpotentials of 70 mV for HER and 225 mV for OER at 10 mA cm⁻², with excellent stability for 100 h at 100 mA cm⁻². For the overall water splitting, it requires only 1.54 V to reach 10 mA cm⁻² and maintains stability for 100 h at 100 mA cm⁻². Therefore, this study provides a new approach for the preparation of high-performance self-supported non-noble metal-based electrocatalysts for water splitting. Full article

Ammonia nitrogen is a key indicator for evaluating drinking water quality, and its accurate determination is of great significance for environmental monitoring and public health protection. In this work, a self-supported electrochemical sensor based on PtCo alloy nanosheets was fabricated on carbon cloth via a one-step electrodeposition strategy. The nanosheet structure facilitates the exposure of abundant electroactive sites and promotes efficient electron transfer. Electrochemical measurements indicate that the PtCo/CC electrode exhibits higher electrocatalytic activity toward ammonia oxidation than monometallic Pt, which can be attributed to the modulation of the Pt electronic structure induced by Co incorporation. Under linear sweep voltammetry, the optimized electrode exhibits a high sensitivity of 32.94 μA μM⁻¹ cm⁻² in the concentration range of 0.7–10 μM and 11.43 μA μM⁻¹ cm⁻² in the range of 10–100 μM, with a low detection limit of 77.9 nM. In addition, the electrode maintains good selectivity in the presence of common interfering ions, along with satisfactory reproducibility and stability. The feasibility of practical application is further confirmed by real water sample analysis. Overall, this work provides an effective strategy for the design of Pt-based alloy electrodes for ammonia nitrogen detection, with potential applications in drinking water quality monitoring. Full article

Efficient and durable non-noble catalysts are crucial for alkaline hydrogen evolution (HER), and high-entropy alloys (HEAs) offer a promising platform due to their multicomponent synergy and tunable surface chemistry. Herein, self-supported nanoporous high-entropy alloy electrodes, Fe₃₅Co₂₅Ni₃₀Mo₁₀ and Fe₃₅Co₂₅Ni₃₀Mo₇W₃, were prepared by arc melting followed by electrochemical dealloying in 1 M HCl. XRD results show that both alloys retain an FCC framework after dealloying, whereas SEM reveals that W promotes a more continuous sponge-like nanoporous structure. In 1 M KOH, dealloyed Fe₃₅Co₂₅Ni₃₀Mo₇W₃ shows enhanced HER activity, requiring an overpotential of 178 mV at 10 mA cm⁻², which is lower than that of dealloyed Fe₃₅Co₂₅Ni₃₀Mo₁₀ and the precursors. Dealloyed Fe₃₅Co₂₅Ni₃₀Mo₇W₃ also exhibits faster kinetics (Tafel slope 98.5 mV dec⁻¹; Rct 3.33 Ω) and a larger C_dl (19.2 mF cm⁻²) than dealloyed Fe₃₅Co₂₅Ni₃₀Mo₁₀. These results highlight W-enabled dealloying-induced reconstruction as an effective route to robust nanoporous HEA electrodes for alkaline HER. Full article

Direct methanol fuel cells (DMFCs) offer significant advantages including high energy density and rapid refueling, making them promising power sources for portable electronic products. However, their practical application, particularly in passive systems, is hindered by critical mass transport limitations: water flooding in the cathode and CO₂ bubble blockage in the anode. Herein, a novel dual-gradient patterned wettability current collector (CC) was designed to alleviate this mass transport impedance. The design uniquely integrates wedge-shaped gradients with surface energy gradients to create a unified, self-driven mechanism for efficient water and CO₂ bubble transport at both electrodes. A mathematical model was developed to quantitatively evaluate the effects of the dual-gradient structure. The results confirm that water removal is enhanced when the cathode current collector features a hydrophobic periphery with a dual-gradient patterned wettability interior on the gas-diffusion-layer side and a fully hydrophilic air-side surface, whereas an inverted pattern facilitates anode CO₂ removal. Optimal fabrication parameters on 316 L stainless steel were established by investigating laser scanning conditions and low-surface-energy agent concentrations. The experimental results show that the passive DMFCs incorporating the optimized current collectors delivered marked performance improvements. At 1 mol·L⁻¹ methanol, the novel anode and cathode current collectors increased peak power density by 15.6% and 14.5%, respectively. Electrochemical impedance spectroscopy revealed a 31.4% and 31.9% reduction in mass transfer resistance of the cell with novel anode and cathode current collectors, respectively, confirming improved gas–liquid self-driven efficiency. Furthermore, the new cells exhibited substantially enhanced long-term stability over 18 h of continuous discharge, attributed to the robust wettability achieved via laser–silane modification. Overall, these findings suggest that the proposed dual-gradient wettability design is a promising method for improving internal mass transport, potentially supporting the development of more robust passive DMFCs. Full article

Pulsed polarization of Au|YSZ gas sensors is examined to clarify the mechanism of NO_x detection under dynamic operation and to disentangle catalytic surface effects from electrochemical relaxation. Using gold electrodes with substantially lower catalytic activity than platinum explicitly enables this mechanistic separation. During pulsed polarization, periodic voltage pulses are followed by self-discharge under open-circuit conditions, and the response is measured based on the self-discharge rate. NO₂ consistently accelerates the self-discharge from the beginning, whereas NO slows the relaxation predominantly at later times. CO and H₂ produce similar delaying effects, and C₃H₆ shows no measurable influence under the tested conditions. Decreasing ambient O₂ slows the discharge and amplifies the NO₂ effect, which indicates that oxygen supply and surface exchange at the triple-phase boundary are rate determining. A Pt-containing catalytic overlayer drives local NO/NO₂ interconversion toward equilibrium so that both gases yield to an accelerated self-discharge. These findings support a mechanistic picture in which NO₂ provides effective oxygen equivalents that accelerate discharge, whereas NO, CO, and H₂ consume oxygen and slow down discharge. Overall, this establishes a materials-based approach for distinguishing between NO and NO₂ and evaluating the underlying mechanism during pulsed polarization. Full article

With the advancement of automation and intelligent manufacturing, mechanical vibration monitoring has become crucial for equipment health assessment. This study proposes a triboelectric nanogenerator (TENG)-based vibration sensor featuring a silicone rubber composite structure. The sensor comprises a silicone rubber layer sandwiched between polyethylene terephthalate (PET) films backed by conductive fabric electrodes, all supported on a polylactic acid (PLA) arch frame. Through systematic structural optimization, the device employing Dragon Skin-30 silicone (1 mm thickness) and conductive fabric electrodes achieved a significant enhancement in output voltage and superior sensitivity compared to initial designs. The optimized sensor operates over a broad detection range for acceleration (5–50 m/s²), amplitude (0.1–2 mm), and frequency (1–300 Hz), and exhibits high linearity (R² ≥ 0.97974) in acceleration sensing. Quantitative comparison with existing triboelectric nanogenerator (TENG) vibration sensors confirms that the proposed SR-TENG outperforms most reported devices in terms of comprehensive detection range and linear sensing performance. Durability tests over 2 h confirmed stable output without degradation. Practical validation on marine blower equipment demonstrated accurate frequency monitoring, closely matching actual vibration characteristics. This work presents a novel approach to self-powered vibration sensing and supports the development of intelligent, sustainable industrial monitoring systems. Full article

In this work, Fe, Co, Ni, Cu, and Mo powders were used as starting materials to prepare high-entropy alloy (HEA) thin films by a coating and vacuum sintering process. Using the HEA thin film as the substrate, selenium was subsequently deposited by chemical vapor deposition (CVD) to obtain high-entropy alloy selenide thin films (HEASe). The phase structure, surface chemical states, morphology, and elemental distribution of the porous films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The electrocatalytic hydrogen evolution performance of the electrodes was evaluated using a three-electrode configuration in 0.5 M H₂SO₄, 1 M KOH, 1 M KOH + 0.5 M NaCl, and 1 M KOH + 0.5 M Na₂S solutions. The results indicate that the HEA selenide thin-film electrodes exhibit favorable electrocatalytic behavior in all four electrolytes. Among them, HEASe-450 shows the best overall performance. In 0.5 M H₂SO₄, it requires an overpotential of only 57.6 mV to reach a current density of 10 mA cm⁻², with a Tafel slope of 146.96 mV dec⁻¹. In 1 M KOH, the overpotential at 10 mA cm⁻² is 50.1 mV, and the corresponding Tafel slope is 142 mV dec⁻¹. In 1 M KOH + 0.5 M NaCl, the overpotential is 52.7 mV with a Tafel slope of 122.72 mV dec⁻¹. In 1 M KOH + 0.5 M Na₂S, an overpotential of 85 mV is required, and the Tafel slope increases to 236 mV dec⁻¹. Full article

Hollow graphitic nanoshells (HGSs) are widely investigated as battery materials because their conductive shells and internal voids can simultaneously influence ion transport, electron percolation, and mechanical stress accommodation. Yet, the field remains largely morphology-driven, with performance often attributed generically to “hollowness” rather than to structural parameters. This review examines HGSs from a parameter-oriented perspective. It highlights key structural features, including graphitization degree, shell thickness, cavity size, pore architecture, and defect or dopant chemistry. These features collectively shape electrochemical behavior. We discuss how these features influence transport kinetics, interphase stability, volumetric efficiency, and mechanical resilience across insertion, metal anode, multivalent, solid-state, and halogen chemistries. Major synthesis approaches, including hard-templated, soft-templated, self-templated, and biomass-derived routes, are evaluated based on the structural control they provide and the influence of synthesis conditions on shell architecture, graphitic ordering, and pore structure. Special attention is given to how these structural features develop during processing and how they affect ion accessibility, conductivity, and stability. Finally, we outline a shift toward quantitative, parameter-driven engineering supported by operando diagnostics, electrode-level modeling, and standardized reporting. HGSs will only achieve practical relevance when structural optimization extends beyond particle morphology to transport uniformity, interfacial stability, network connectivity, and life-cycle responsibility. Full article

Magnetic-field-assisted electrocatalysis offers a powerful route to enhance the oxygen evolution reaction (OER) by coupling spin-dependent effects with magnetohydrodynamic phenomena. Here, we present a unified study of cobalt ferrite (CoFe₂O₄)-based nanofilms, elucidating the combined roles of rare-earth doping, nanoparticle size, film morphology, and electrode substrate magnetism on OER performance under external magnetic fields. The effect of UV-light irradiation is also investigated. CoFe₂O₄ and yttrium-doped CoFe₂O₄ nanoparticles were synthesized via thermal decomposition and self-combustion routes, yielding single-domain particles with distinct structural and magnetic properties, and assembled into homogeneous nanofilms using the Langmuir–Blodgett technique. Electrocatalytic measurements in alkaline media reveal that intrinsic OER activity is primarily governed by film compactness and charge-transfer efficiency, while the magnitude of magnetic-field-induced enhancement depends on the magnetic response of both the nanofilms and the supporting electrode. Ferromagnetic substrates promote enhanced catalytic activity under magnetic fields, whereas diamagnetic substrates can exhibit suppressed performance. Across all systems, the strongest enhancement is observed when the magnetic field is applied parallel to the electrode surface, reflecting the combined effects of spin polarization and Lorentz-force-driven mass transport. UV-light irradiation is also evaluated as an external stimulus to promote the reaction. Our findings establish a comprehensive framework for designing magnetically assisted OER electrocatalysts and demonstrate that magnetic-field effects can rival or complement rare-earth doping or UV-light irradiation, offering a sustainable pathway toward high-efficiency water oxidation. Full article

The relatively poor cycle stability of zinc–air batteries (ZABs) hinders their widespread application, while self-supporting electrode materials have shown great potential in enhancing the cycling stability of ZABs. To construct a self-supporting electrode, bamboo was employed as a sustainable precursor, and a two-step pyrolysis strategy was implemented to integrate ZIF-67-derived catalysts onto a hierarchically porous carbon framework, yielding the composite material Co-N@CB. Benefiting from its structural and electronic advantages, Co-N@CB exhibits outstanding electrocatalytic performance. The overpotential for the oxygen evolution reaction (OER) in alkaline electrolyte is 1.5 V at 10 mA cm⁻², with a potential gap (ΔE) of 0.69 V. This material is directly used as the air cathode in ZABs, delivering over 10,000 stable cycles. This excellent cycling stability arises from the strong carbon framework provided by bamboo and the enhanced electrical conductivity achieved through the pyrolytic graphitization of ZIF-67. This study paves the way for further exploration of biomass-based self-supporting electrodes toward high-performance ZABs and emerging micro/nanoscale sensing technologies. Full article

Cellulose nanofibers/metal-organic framework (CNFs/MOF) composites hold promise for energy storage thanks to high porosity, large specific surface area, and inherent flexibility, but their poor conductivity limits applications to environmental remediation and gas adsorption. Herein, flexible CNFs served as substrates for in situ growth of continuous ZIF-8 nanolayers via interfacial synthesis, with a CNFs/ZIF-8 gel network built to enhance structural integrity and flexibility. A novel strategy first regulated the layered pore structure: ZIF-8 in CNFs/ZIF-8 nanofibers was etched in the acidic environment of aniline in situ polymerization, constructing a hierarchical porous architecture with interconnected micropores and mesopores. CNFs/ZIF-8/PANI gel composite membranes were then fabricated. As self-supporting electrodes for symmetric supercapacitors, the composites showed excellent electrochemical performance: 1350 F/g at 1 A/g for the electrode, and the flexible solid-state device delivered a specific capacitance of 220.9 F/g at 0.5 A/g, along with a capacitance retention rate of 74% after 5000 charge–discharge cycles at 10 A/g. The superior performance stems from synergistic hierarchical pore structure regulation via partial MOF sacrificial templating and gel matrix-mediated rapid ion diffusion, offering a feasible approach for high-performance flexible energy storage devices. Full article

The plasma-catalytic conversion of CO₂ is a promising route toward sustainable fuel and chemical production under mild operating conditions. However, many aspects still need to be better understood to improve performance and better understand the catalyst-plasma synergies. Among them, one aspect concerns understanding whether photons emitted by plasma discharges could induce changes in the catalyst, thereby promoting interaction between plasma species and the catalyst. This question was addressed by investigating the CO₂ splitting reaction in a planar dielectric barrier discharge (pDBD) reactor using titania-based catalysts that simultaneously act as discharge electrodes. Four systems were examined feeding pure CO₂ at different flow rates and applied voltage: bare titanium gauze, anodically formed TiO₂ nanotubes (TiNT), TiNT decorated with Ag–Au nanoparticles (TiNTAgAu), and TiNT supporting Ag–Au nanoparticles coated with polyaniline (TiNTAgAu/PANI). The TiNTAgAu exhibited the highest CO₂ conversion (35% at 10 mL min⁻¹ and 5.45 kV) and the most intense optical emission, even in the absence of external light irradiation, suggesting that the improvement is primarily attributed to plasma–nanoparticle interactions and self-induced localized surface plasmon resonance (si-LSPR) rather than conventional photocatalytic pathways. SEM analyses indicated severe plasma-induced degradation of TiNT and TiNTAgAu surfaces, leading to performance decay over time. In contrast, the TiNTAgAu/PANI catalyst retained structural integrity, with the polymeric coating mitigating plasma etching while maintaining competitive efficiency. There is thus a complex behavior with catalytic performance governed by nanostructure stability, plasmonic enhancement, and the interfacial protection. The results demonstrate how integrating plasmonic nanoparticles and conductive polymers can enable the rational design of durable and efficient plasma-photocatalysts for CO₂ valorization and other plasma-assisted catalytic processes. Full article

Electrospinning has emerged as a powerful technique for fabricating customised nanofibrous materials with integrated functional nanostructures, offering significant advantages for electrochemical energy applications. This review highlights recent advances in using electrospun nanofibres directly as active components in devices such as batteries, supercapacitors, and fuel cells. The emphasis is on the role of composite design, fibre morphology and surface chemistry in enhancing charge transport, catalytic activity and structural stability. Integrating carbon-based frameworks, conductive polymers, and inorganic nanostructures into electrospun matrices enables multifunctional behaviour and improves device performance. The resulting nanofibrous composite materials, often after heat treatment, can be used directly as electrodes or self-supporting layers, eliminating the need for additional processing steps such as size reduction or preparation of slurries and inks for creating functional nanofibre-based deposits. The importance of composite nanofibres as an emerging strategy for overcoming challenges related to scalability, long-term durability, and interface optimisation is also discussed. This review summarises the key results obtained to date and highlights the potential of electrospun nanofibres as scalable, high-performance materials for next-generation energy technologies, outlining future directions for their rational design and integration. Full article

This paper introduces an innovative EEG sensor-based computational framework that establishes a pioneering nexus between personality trait quantification and neural dynamics, leveraging biosignal processing of brainwave activity to elucidate their intrinsic influence on cognitive health and oscillatory brain rhythms. By employing electroencephalography (EEG) recordings from 21 participants undergoing the Trier Social Stress Test (TSST), we propose a machine learning (ML)-driven methodology to decode the Big Five personality traits—Extraversion (Ex), Agreeableness (A), Neuroticism (N), Conscientiousness (C), and Openness (O)—using classification algorithms such as support vector machine (SVM) and multilayer perceptron (MLP) applied to 64-electrode EEG sensor data. A novel multiphase neurocognitive analysis across the TSST stages (baseline, mental arithmetic, job interview, and recovery) systematically evaluates the bidirectional relationship between personality traits and stress-induced neural responses. The proposed framework reveals significant negative correlations between frontal–temporal theta–beta ratio (TBR) and self-reported Extraversion, Conscientiousness, and Openness, indicating faster stress recovery and higher cognitive resilience in individuals with elevated trait scores. The binary classification model achieves high accuracy (88.1% Ex, 94.7% A, 84.2% N, 81.5% C, and 93.4% O), surpassing the current benchmarks in personality neuroscience. These findings empirically validate the close alignment between personality constructs and neural oscillatory patterns, highlighting the potential of EEG-based sensing and machine-learning analytics for personalized mental-health monitoring and human-centric AI systems attuned to individual neurocognitive profiles. Full article

Electrochemiluminescence (ECL) is a chemiluminescence phenomenon triggered by electrochemical reactions at the electrode surface, which has gradually become a high-sensitivity detection technology due to its low background, simple instrumentation, and high sensitivity. Therein, potential-resolved ECL refers to the generation of two or more ECL signals with distinct potentials and wavelengths during an electrochemical process. This unique capability enables simultaneous multi-signal outputs, making potential-resolved ECL particularly promising for self-calibration and multiplexed detection strategies. In this review, we focus on two critical aspects: on the one hand, the advancement of traditional ECL luminophores and potential-resolved ECL systems was reviewed, which were classified, respectively, into three categories to be introduced in detail (inorganic, organic and nanomaterial-based ECL luminophores or potential-resolved ECL of metal–organic complexes, layer-by-layer-modified electrodes, and nanomaterials). On the other hand, we summarized ECL detection strategies based on potential-resolved ECL systems and the application of these protocols in disease biomarker detection, which results in two categories (self-calibration strategies and multi-target strategies) for discussion. In this work, we aim to inspire investigators to explore novel ECL luminophores and design detection strategies with high performance, which could provide strong support for precision medicine, personalized assessment, portable medical devices, and the digital transformation of healthcare. Full article