Search Results (346)

Potassium-ion batteries hold great promise for large-scale energy storage, but their commercialization is hindered by the large ionic radius of potassium, which causes sluggish kinetics and severe volume expansion in anode materials. To address this, we present a scalable spray-drying strategy coupled with NaCl salt-templating to synthesize hierarchical porous carbon/vanadium sulfide microspheres (p-V₃S₄/C MS). In this structure, V₃S₄ nanoparticles are uniformly encapsulated within a dextrin-derived amorphous carbon matrix, and pores are formed via selective NaCl etching. This unique architecture accommodates volume fluctuations while providing rapid ion diffusion pathways. As a result, the p-V₃S₄/C MS anode exhibits outstanding electrochemical performance, maintaining a reversible capacity of 107 mA h g⁻¹ after 2000 cycles at 2.0 A g⁻¹, and achieves a high pseudocapacitive contribution of 93% at 2.0 mV s⁻¹. Furthermore, a full cell paired with a Prussian blue (PB) cathode demonstrates practical viability and robust reversibility. Our findings demonstrate that this structural engineering effectively mitigates internal resistance and structural degradation, offering a cost-effective route for mass-producing high-performance anodes for next-generation energy storage. Full article

Hepatic encephalopathy is a severe complication of liver failure, traditionally investigated through brain–liver interactions; however, the involvement of extrahepatic organs remains poorly understood. This study examined splenic histopathological changes in a mouse model of acute hepatic encephalopathy induced by ammonium acetate administration, focusing on iron metabolism and macrophage activation. Although conventional hematoxylin and eosin staining revealed no overt structural abnormalities, unstained spleen sections demonstrated abundant black deposits, predominantly in the red pulp. Prussian blue staining confirmed a significant increase in hemosiderin-positive cells; however, a subset of black deposits was iron-negative. Immunohistochemical analyses revealed that these iron-negative pigments were localized within F4/80-positive macrophages and colocalized with heme oxygenase-1 (HO-1), suggesting enhanced heme degradation. Ultrastructural observations further identified electron-dense granules consistent with hematin accumulation in splenic macrophages. Hematological analyses revealed significant reductions in red blood cell count and hemoglobin levels, indicating accelerated erythrocyte destruction. Collectively, these findings demonstrate that acute hepatic encephalopathy induces splenic macrophage activation, accompanied by disordered iron metabolism and hematin accumulation. This study highlights the spleen as a previously underappreciated extrahepatic organ involved in the pathophysiology of hepatic encephalopathy and suggests that splenic heme–iron handling may represent a novel therapeutic target. Full article

Sodium-ion batteries (SIBs) are regarded as an important complementary technology to lithium-ion batteries due to their abundant resources and low cost, demonstrating broad application prospects, especially in large-scale energy storage. As a core component of SIBs, the cathode material directly determines key performance indicators such as energy density, cycling stability, and rate capability. Currently, the main cathode material systems under extensive research include transition metal oxides, polyanionic compounds, and Prussian blue analogues (PBAs), each exhibiting distinct characteristics in terms of crystal structure and electrochemical performance. Transition metal oxides have attracted significant research interest owing to their high specific capacity, while polyanionic compounds are known for their excellent structural stability and operating voltage. PBAs, on the other hand, have gained considerable attention due to their open framework structure and simple synthesis process. In recent years, modification strategies such as nanostructure engineering, surface coating, and elemental doping have significantly enhanced the electrochemical performance of these cathode materials. Future research should focus on addressing critical scientific challenges, including low intrinsic electronic conductivity and poor interfacial stability, while also exploring novel composite cathode material systems to facilitate the practical application of sodium-ion batteries. Full article

There is an increasing demand for multifunctional devices, that can operate simultaneously as energy storage and electrochromic display devices, widely known as electrochromic supercapacitors. For instance, Prussian blue (PB) exhibits outstanding electrochromic properties; however, it has not been well explored for energy storage applications. Moreover, the electrochemical properties can be enhanced by surface engineering the host material via compositing with conducting polymers. In this work, we studied the electrochromic supercapacitor properties of composites such as Prussian blue-polyaniline (PB-PANI). The PB-PANI 90 composite thin-film electrode exhibited the highest coloration efficiency of 461.39 cm²/C and demonstrated superior electrochemical performance, with an aerial capacitance of 50.80 mF/cm² and an optical modulation of 19.4%. All samples achieved rapid switching times of less than 3 s. These findings highlight the potential of optimizing conducting polymer coatings on Prussian blue to achieve a well-balanced composite structure with enhanced morphological properties, paving the way for advanced multifunctional electrochromic supercapacitor devices in next-generation smart systems. Full article

This study focuses on the synthesis and characterization of buckwheat husk-derived activated carbon, chemically activated with potassium hydroxide (KOH) and subsequently modified with urea and Prussian Blue (PB). The obtained carbons were evaluated in terms of particle-size distribution, surface morphology, structural features, and electrokinetic properties using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and electrophoresis, as well as N₂ adsorption–desorption (BET surface area and porosity analysis). The results confirmed that both pyrolysis conditions and the type of modifier significantly affect the physicochemical properties of the activated carbon and its behavior in electrolyte solutions. Colloidal stability and particle size were strongly dependent on pH and the type of anions present in solution, with sodium nitrate (NaNO₃) systems showing higher stability than sodium chloride (NaCl). Modification with KOH and urea imparted a more basic surface character, whereas PB introduced more acidic properties. All samples exhibited predominantly negative surface charges and mesoporous structures, which are favorable for adsorption processes and enhance affinity for heavy-metal cations. Among the tested materials, BH-KOH-Fe (Fe-modified KOH-activated carbon) showed the most favorable performance for the targeted application, while BH-KOH (KOH-activated buckwheat husk-derived carbon) exhibited high surface area and good colloidal stability. The prepared materials show promising applicability for water purification, including the removal of organic pollutants and radionuclides (e.g., ¹³⁷Cs and ⁹⁰Sr), as well as metal cations (K⁺, Na⁺, and Li⁺). Full article

Background/Objectives: The precise elimination of Schistosoma japonicum eggs within host tissues poses a significant therapeutic obstacle due to the ineffectiveness of existing drugs in penetrating the eggs’ protective shields. This investigation sought to create a surface-modified magnetic nanoparticle (MNP) framework to surmount this hurdle and realize targeted theranostics for combating schistosomiasis. Methods: Fe₃O₄ MNPs, MNP-NH₂, and MNP-COOH were synthesized and characterized before systematically studying their interactions with parasites. The intrinsic autofluorescence of eggs and adult worms served as an optical background for the investigation. In vitro co-incubation assays, confocal microscopy, and Prussian blue staining were utilized to quantify both adsorption and internalization. The in vivo efficacy was assessed in a Schistosoma japonicum murine model following tail vein injection. Results: A pronounced surface chemistry-dependent interaction was noted. Fe₃O₄ MNP and MNP-NH₂ displayed remarkable adsorption and effective internalization into eggs in vitro, while MNP-COOH exhibited limited uptake. This varying effectiveness was similarly observed in vivo, with Fe₃O₄ MNP and MNP-NH₂ predominantly gathering in hepatic granulomas and effectively infiltrating deposited eggs. Within adult worms, Fe₃O₄ MNP and MNP-COOH exhibited distribution on the tegument and within adult worms. Conclusions: We developed a functional MNP platform in which surface charge governs parasiticidal targeting. Among the candidates investigated, MNP-NH₂ proved to be the most efficient for egg-targeted theranostics. This study introduces an innovative nanotechnology-based approach for accurate diagnosis and treatment of schistosomiasis by specifically tackling the challenge of impermeable eggs. Full article

Seawater electrolysis offers a promising route for sustainable hydrogen production in coastal areas, leveraging solar energy while reducing freshwater consumption. Yet, chloride-induced corrosion severely limits conventional electrodes such as titanium, which depend on passive titanium dioxide films and display minimal hydrogen evolution reaction activity (|i₀,H₂| ≈ 0.001–0.01 A/m²). Here, we report for the first time the use of copper-based coordination compounds—a triazole-derived polymer (CC_Cu) and a Prussian Blue Analogue (CuHCF)—as dual-function electrodes combining corrosion resistance with electrocatalytic activity. Structural integrity was verified by FTIR, TGA, XRD, and SEM/EDS analyses. Electrochemical tests in 0.5 M NaCl, interpreted using mixed potential theory, revealed corrosion potentials (E_corr) of −40 mV versus Standard Hydrogen Electrode (CuHCF) and −23 mV versus Standard Hydrogen Electrode (CC_Cu), and corrosion current densities of 0.259 and 0.379 A/m², respectively. Both exhibited hydrogen evolution reaction exchange current densities significantly higher than titanium (0.019 A/m² for CuHCF and 0.062 A/m² for CC_Cu). CuHCF achieved a Tafel slope of 222 mV/dec, comparable to NiMoP alloys and carbon steel. Complementary density functional theory calculations elucidated how metal–ligand interactions and electronic redistribution govern both catalytic performance and degradation. These findings introduce a new concept of semi-electrocatalysts, where copper coordination compounds act as structurally adaptive, low-cost materials bridging corrosion resistance and hydrogen evolution in seawater systems. Full article

This article presents a comprehensive analysis of the polychrome paintings on the Flower Peking Opera Theatre in Bozhou, Anhui Province, China. A multi-technique approach was employed, including polarized light microscopy (PLM), X-ray fluorescence (XRF), micro-Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS), and Herzberg staining to determine the composition and methodologies involved in the formation of the pigment layer, the white primer, and the ground layer. The analysis identified cinnabar (red), both artificial ultramarine and Prussian blue (blue), a mixture of barite and gypsum (white), a mixture of chromite and Prussian blue (green), and carbon black (black) in the pigment layer. The ground layer was found to consist of clay and plant fibers (cotton and hemp), while the white prime layer was primarily composed of barite and gypsum. This research provides insights for future conservation and restoration efforts. Full article

Mammary gland tumors are among the most common neoplasms in female dogs. Macrophages are believed to play an important role in tumor progression and metastasis. The aim of this study was to determine whether hemosiderin-laden macrophages (HLMs) may be involved in the development of metastatic lesions in regional lymph nodes. Forty-two cases of mammary gland cancers in female dogs and their regional lymph nodes were included in the analysis. The samples were divided into two groups based on the presence or absence of metastases. The sections were stained with hematoxylin and eosin (HE) and Prussian blue and were additionally subjected to immunohistochemical labeling using antibodies against pan-cytokeratin (Pan-CK) and Ki-67. In 20 cases, no metastatic changes were detected in the regional lymph node, whereas metastases were identified in 22 cases. A positive correlation was observed between the number of HLMs in the tumor stroma and the number of HLMs in the regional lymph node. Furthermore, a positive correlation was found between Ki-67 nuclear immunoreactivity in the mammary tumor and the number of HLMs present within its stroma. HLMs may represent a component of the tumor microenvironment that promotes cancer cell proliferation and potentially contributes to the propensity for metastasis formation in mammary tumors of female dogs. Full article

Redox mediators are central to electrochemical biosensors, enabling electron transfer between deeply buried enzymatic cofactors and electrode surfaces when direct electron transfer is kinetically inaccessible. Among all design parameters, the reversibility of mediator redox cycling remains the most decisive yet under-examined factor governing biosensor stability, drift and long-term reproducibility. This review establishes reversibility as a unifying framework grounded in inorganic and organometallic redox chemistry, with particular emphasis on coordination environments, ligand-field effects and outer-sphere electron-transfer pathways. Recent advances (2010–2025) in ruthenium and osmium polypyridyl complexes, cobalt macrocycles, hexacyanoferrates and Prussian Blue analogues are examined alongside ferrocene derivatives and other organometallic mediators, which together define the upper limits of reversible behaviour. Organic mediator families, including quinones, phenazines, indophenols, aminophenols and viologens, are discussed as mechanistic contrasts that highlight the structural and thermodynamic constraints that limit long-term cycling in aqueous media. Mechanistic indicators of reversibility, including peak separation, current ratios and heterogeneous electron-transfer rate constants, are linked to mediator architecture, coordination chemistry and immobilisation environment. By integrating molecular electrochemistry with applied sensor engineering, this review provides a mechanistically grounded basis for selecting or designing redox mediators that sustain efficient electron transfer, minimal fouling and calibration stability across diverse sensing platforms. Full article

This Perspective sets out to raise awareness about the chemical and photophysical properties of an assortment of blue colorants; it is generally regarded that blue is the most popular color worldwide and is recognized for its serenity and calming effect. In fact, blue colorants have a long and rich history, perhaps starting with Egyptian Blue, and have found colossal usage in the dyeing of uniforms and popular clothing. Other blue colorants have made major contributions to our understanding of the fields of molecular spectroscopy and photophysics and continue to underpin contemporary opto-electronic devices. This is in addition to their socio-cultural, economic, and ecological benefits to society. Originally, blue colorants were extracted from minerals by tedious and ineffectual grinding to give a product carrying an exorbitant price. Later, these materials were supplemented by synthetic analogues, such as copper phthalocyanine, more affordable to the general public. It is stressed that the journal Colorants would welcome submissions that describe the chemistry and/or spectroscopy of other archetypal colorants. Full article

This review presents a critical and comparative analysis of carbon-based electrochemical sensing platforms for the determination of heavy metal ions in water, with emphasis on Pb²⁺, Cd²⁺, and Hg²⁺. The growing discharge of industrial and mining effluents has led to persistent contamination of aquatic environments by toxic metals, creating an urgent need for sensitive, rapid, and field-deployable analytical technologies. Carbon-based nanomaterials, including graphene, carbon nanotubes (CNTs), and MXene, have emerged as key functional components in modern electrochemical sensors due to their high electrical conductivity, large surface area, and tunable surface chemistry. Based on reported studies, typical detection limits for Pb²⁺ and Cd²⁺ using differential pulse voltammetry (DPV) on glassy carbon and thin-film electrodes are in the range of 0.4–1.2 µg/L. For integrated thin-film sensing systems, limits of detection of 0.8–1.2 µg/L are commonly achieved. MXene-based platforms further enhance sensitivity and enable Hg²⁺ detection with linear response ranges typically between 1 and 5 µg/L, accompanied by clear electrochemical or optical signals. Beyond conventional electrochemical detection, this review specifically highlights self-sustaining visual sensors based on MXene integrated with enzyme-driven bioelectrochemical systems, such as glucose oxidase (GOD) and Prussian blue (PB) assembled on ITO substrates. These systems convert chemical energy into measurable colorimetric signals without external power sources, enabling direct visual identification of Hg²⁺ ions. Under optimized conditions (e.g., 5 mg/mL GOD and 5 mM glucose), stable and distinguishable color responses are achieved for rapid on-site monitoring. Overall, this review not only summarizes current performance benchmarks of carbon-based sensors but also identifies key challenges, including long-term stability, selectivity under multi-ion interference, and large-scale device integration, while outlining future directions toward portable multisensor water-quality monitoring systems. Full article

Prussian blue (PB) and its analogs (PBAs) are interesting materials for electrochemical applications due to their tunable redox chemistry and open framework structure. In this study, hexacyanoferrates (HCF) containing iron (FeHCF), cobalt (CoHCF), and nickel (NiHCF) were synthesized via potentiostatic electrodeposition. Cyclic voltammetry revealed distinct redox behaviors. Morphological characterization (SEM, EDX) demonstrated uniform, pyramidal film growth for FeHCF and CoHCF. Otherwise, NiHCF presented a cracked film with cubic clusters on top due to residual stress. Despite this, homogeneous element distribution was found for all samples. Structural characterization (TEM and XRD) confirmed a cubic lattice crystal structure for all films, with systematic lattice contraction from Fe to Co to Ni due to decreasing atomic radius. Raman and XPS data revealed a shift toward Fe²⁺ dominant oxidation states and modifications in C≡N bonding, with the influence of K⁺ and water occupancy in the PBAs framework. These findings illustrate how metal substitution and deposition parameters can tune the structural and electrochemical properties of PBA films, presenting a strategic route to design tailored electrodes. Full article

Cobalt-based Prussian blue hollow spheres (CoHCF HSs) with different Co contents were synthesized using a self-templated coprecipitation technology. The microstructure and electrochemical properties of CoHCF HSs were investigated. The results indicate that all samples exhibit a face-centered cubic crystal structure. With increasing cobalt content in the Prussian blue analogues, the X-ray diffraction peaks shift toward higher angles due to the reduction in interplanar spacing. Computer simulations revealed that Na⁺ ions exhibit higher adsorption energies (ΔE_a) at Co sites (ΔE_a = 1.45 eV) compared to Fe sites (ΔE_a = 1.18 eV), which enables Co sites to adsorb more Na⁺ ions, providing greater sodium storage capacity. With increasing cobalt content, the reduced aspect ratio of CoHCF HSs surface nanoscale protrusions decreases the specific surface area. Consequently, the overall average CoHCF HSs size decreases with increasing cobalt content, which predominates the increase in specific surface area, contributing to supplying more active sites. The best electrochemical properties showed an initial capacity of 121.16 mAh g⁻¹ at a current density of 0.2 A g⁻¹ but not at the largest specific surface area. These findings suggest that improving the electrochemical performance of CoHCF electrodes requires consideration of the synergistic effects between specific surface area and elemental composition. Full article

To meet the demand for rapid and accurate glucose determination in clinical diagnostics, food testing, and related fields, this study developed a high-performance electrochemical glucose biosensor based on multi-walled carbon nanotubes/Prussian blue/zeolitic imidazolate framework-8@glucose oxidase/chitosan (MWCNTs/PB/ZIF-8@GOx/CS). The MWCNTs/PB conductive network significantly accelerated electron transfer and catalytic activity, while the ZIF-8, with its regular pore structure and high specific surface area, provides an efficient microenvironment for the immobilization and conformational stabilization of glucose oxidase (GOx), thereby improving substrate diffusion and maintaining enzyme activity. The MWCNTs/PB/ZIF-8@GOx/CS sensor demonstrates excellent sensing performance, featuring a wide linear response to glucose concentrations ranging from 4.8 μM to 2.24 mM, a high sensitivity of 579.57 μA/mM/cm², and a low detection limit of 0.55 μM (S/N = 3). In addition, the sensor performs excellent repeatability (RSD = 1.49%) and retained 86.23% of its initial response after 3 weeks of storage at 4 °C, highlighting its strong potential for practical application in glucose detection. Full article