Search Results (3,380)

Sulfathiazole (STH) pollution has been increasing, with a strong need for a sensitive and selective analysis method. In this paper, a three-component fluorescent sensing platform with Mn²⁺-doped ZnS quantum dots in a metal–organic framework coated with a surface molecularly imprinted polymer (Mn-ZnS-MOF-MIP) for selective sensing of sulfathiazole is proposed. This synergistic sensor platform combines Mn-ZnS-insensitive emission, MOF-assisted analyte enrichment, and imprinting-based molecular recognition. The sensing platform displays a characteristic turn-off fluorescence with a dominant static quenching mechanism. Under optimal conditions, a broad sensing range with a low detection limit of 13.75 nM can be obtained. Outstanding selectivity among similar sulfonamides, biomolecules, and metal ions were achieved with high reproducibility, stability, and reusability. This sensing platform was shown to analyze sulfathiazole accurately in aqueous samples and blood serum with high recoveries, within the range of 90.00–104.24%, compared to high-performance liquid chromatography methods. Full article

This study reports the synthesis and comprehensive characterization of a novel 5% cadmium-doped cerium oxide/reduced graphene oxide (5% Cd-CeO₂/rGO) nanocomposite for the enhanced visible-light-driven photocatalytic degradation of methyl orange (MO). The nanocomposite was prepared using a simple co-precipitation method followed by thermal reduction, which integrates the excellent electron-transport properties of reduced graphene oxide (rGO) with the oxygen-vacancy-rich characteristics of Cd-doped CeO₂, resulting in improved photocatalytic performance. The successful synthesis of the nanocomposite and the direct interaction between the rGO sheets and ultrafine CeO₂ nanoparticles were verified through structural and morphological analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). XPS results indicated an increase in the Ce³⁺ concentration and oxygen vacancy density after Cd doping and rGO incorporation, both of which play a crucial role in enhancing photocatalytic activity. Under visible-light irradiation, the 5% Cd-CeO₂/rGO nanocomposite exhibited substantially higher photocatalytic activity and methyl orange (MO) degradation efficiency than pristine CeO₂ and reduced graphene oxide (rGO). The improved photocatalytic performance demonstrates the beneficial role of combining metal-ion doping with conductive carbon supports to facilitate charge separation and electron transport in semiconductor photocatalysts. The developed nanocomposite also shows promising potential for the design of next-generation semiconductor-based materials for photocatalytic, energy conversion, and optoelectronic applications. Full article

Electrocatalytic glycerol oxidation to formic acid (FA) offers a sustainable route for biomass valorization, yet non-noble metal catalysts generally suffer from sluggish C-C bond cleavage and poor product selectivity. Here we report an amorphous nickel–cobalt oxyhydroxide bearing both metal and oxygen vacancies (D-NiCoO_xH_y-V_Cr,O), grown on nickel foam via one-step electrodeposition followed by electrochemical activation with Cr doping. The coexistence of the dual vacancies is experimentally confirmed by X-ray photoelectron spectroscopy (XPS), which reveals elevated Ni³⁺/Co³⁺ ratios and reduced lattice oxygen, and by electron paramagnetic resonance (EPR), which shows a markedly enhanced signal at g = 2.003. Building on prior Cr-leaching approaches in single-metal nickel oxides, this work extends dual-vacancy engineering to an amorphous bimetallic NiCo oxyhydroxide and correlates the defect structure with glycerol-induced interfacial responses, charge-transfer behavior, and product selectivity. The catalyst delivers 200 mA cm⁻² at 1.31 V vs. RHE and achieves 100% Faradaic efficiency for formate at 1.32 V vs. RHE. In situ electrochemical impedance spectroscopy further reveals a significantly reduced charge-transfer resistance. These results establish Cr-assisted dual-vacancy engineering in amorphous bimetallic oxyhydroxides as a promising strategy for selective biomass electrooxidation. Full article

Solar-driven photocatalytic water splitting is a promising approach for green hydrogen production. Despite the great potential of g-C₃N₄ photocatalysts, non-metal doping studies currently suffer from conflicting results and unclear doping configurations. Herein, first-principles calculations were adopted to compare P-, O-, and S-doped g-C₃N₄. P-g-C₃N₄ with P substituting N shows the best stability, a narrower band gap, and enhanced visible light absorption. It achieves high carrier mobility and suitable band edges for overall water splitting, with a maximum STH efficiency of 15.8%. This work clarifies doping mechanisms and offers solid theoretical support for developing high-performance g-C₃N₄-based photocatalysts. Full article

Nuclear relaxation, $1/T_1$, is a very robust probe of electronic excitations in superconducting materials above and below the critical temperature of superconductivity, $T_{\mathrm{c}}$. Here, a relaxation phenomenology of hole-doped cuprate superconductors is presented based on the majority of the available literature data from the CuO₂ plane, without assumptions with respect to a hyperfine scenario, form factors, or particular theoretical models. Below a temperature similar to the pseudogap temperature, Heitler–Teller-type relaxation is uncovered universally; i.e., the nuclear spin relaxation above $T_{\mathrm{c}}$ is only determined by the absolute temperature, $1/T_1\propto T$. All materials condense out of this metal at $T_{\mathrm{c}}$, below which relaxation drops even faster, as expected from conventional superconductors, albeit without a Hebel–Slichter peak. It is a ’hidden metal’ in the sense that it has a vanishing uniform response and thus hardly affects the NMR shifts; it is also not seen in planar O relaxation. The hidden metal causes a temperature-independent but material-dependent planar Cu relaxation anisotropy that is strongly correlated with the size of $T_{\mathrm{c}}$. Moreover, the rate measured with the field in the CuO₂ plane is nearly the same for all cuprates: $1/{{}^{63}T}_{1\perp }T\approx 25/$Ks, where $1/{{}^{63}T}_{1\Vert }$ is mainly responsible for the change in anisotropy. Above the hidden metal, the relaxation behavior changes and can be described by an ordinary but renormalized metal, with a reduced Cu relaxation anisotropy. The relaxation phenomenology, which should hold clues to the so-called strange metal, is also discussed in the context of the two spin components previously uncovered in the shifts, as well as the pseudogap and relation to other probes. This new phenomenology should give a better foundation for the understanding of the cuprates. Full article

Electrocatalytic water splitting offers a viable route to sustainable hydrogen generation, yet the development of non-noble metal catalysts that combine high efficiency with long-term stability remains a significant hurdle. Zeolitic imidazolate framework-67 (ZIF-67) has emerged as a potential electrocatalyst, but its activity is often limited by insufficient active sites and poor conductivity. In this study, Mn, Fe, and Ni doped derivatives of ZIF-67 (ZIF-67/M, M = Mn, Fe, Ni) were synthesized via a post-synthetic modification method to improve the electrocatalytic performance. The effects of metal doping on structure, morphology, and water splitting activity were systematically investigated. XRD and FTIR confirmed the successful incorporation of heteroatoms without destroying the crystalline framework, while TGA revealed altered thermal stability. BET measurements showed a transformation from microporous to mesoporous structures upon doping, and SEM exhibited crystal distortion, aggregation, and increased surface roughness. Electrochemical tests demonstrated that doping significantly enhanced both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performances. At 10 mA cm⁻², ZIF-67/Fe exhibited the lowest overpotentials for OER (271 mV) and HER (338 mV), outperforming ZIF-67/Mn, ZIF-67/Ni, and pristine ZIF-67. Overall water splitting tests on ZIF-67/Fe showed negligible overpotential change after 24 h, confirming good ambient stability. In summary, metal doping effectively enhances the electrocatalytic water splitting performance of ZIF-67 by modulating its coordination environments and active site distribution, with ZIF-67/Fe exhibiting the best overall performance as a promising bifunctional electrocatalyst. Full article

Coupling renewable energy with seawater electrolysis is a highly promising strategy for sustainable hydrogen production. However, the practical application of direct seawater electrolysis remains challenging due to severe anode corrosion and the competitive chlorine evolution reaction (CER) induced by chloride ions. Herein, we report a facile cation-etching strategy to synthesise Fe@ZIF-67 catalysts at room temperature, using ZIF-67 as the sacrificial template and Fe²⁺ salts as the etching agent. The as-prepared Fe@ZIF-67 exhibits superior electrocatalytic activity for the oxygen evolution reaction (OER) in a simulated alkaline saline electrolyte (1.0 M KOH + 0.5 M NaCl). Specifically, it achieves a current density of 10 mA cm⁻² at a low overpotential of 259 mV, outperforming commercial RuO₂. Furthermore, an alkaline saline electrolyser assembled with Fe@ZIF-67 as the anode and Pt/C as the cathode requires a cell voltage of only 1.57 V to reach 10 mA cm⁻², which is significantly lower than that of the RuO₂||Pt/C benchmark (1.65 V). This work demonstrates that the cation-doping strategy effectively modulates the surface electronic structure of metal–organic frameworks (MOF)-based catalysts, providing a new perspective for optimising their performance in seawater electrolysis. Full article

Vanadium dioxide (VO₂), a typical thermochromic material, undergoes a metal–semiconductor transition (MST) near 68 °C, accompanied by lattice distortion and band structure reconstruction, making it an ideal material for smart window applications. However, VO₂ faces several bottlenecks that limit its engineering applications, including a relatively high phase transition temperature, poor color comfort, trade-offs between visible light transmittance and solar modulation efficiency, and inadequate long-term stability. This paper first discusses the structural evolution and mechanisms of the VO₂ phase transition. It then focuses on the three core performance aspects of VO₂-based smart windows: phase transition temperature regulation, color regulation, and optical performance regulation. Furthermore, it systematically reviews the latest research advancements in key technologies, including elemental doping, interfacial strain engineering, micro- and nanostructure engineering, multilayer film design, and inorganic–organic composite modification. Finally, the paper analyzes current challenges in terms of long-term stability, low-temperature flexible fabrication, skin comfort, and environmental friendliness, and discusses optimization pathways and future prospects for the practical application of VO₂-based smart windows. Full article

Biochar is a porous carbonaceous material synthesized through the pyrolysis of diverse biomass resources, including agricultural and forestry residues as well as livestock manure. It possesses superior characteristics such as a large specific surface area, adjustable pore architecture, abundant surface functional groups, and favorable electrical conductivity. With the increasingly severe global energy shortage and environmental pollution problems in recent years, biochar has emerged as a green, low-cost functional material with distinct application superiority in multiple key research directions, including energy storage and conversion, chemical catalysis, environmental restoration, and signal sensing and detection. This study comprehensively summarizes the latest research advances of biochar in the aforementioned application fields, focusing on innovative achievements in photocatalytic and electrocatalytic hydrogen generation, supercapacitors and electrochemical energy storage systems, persulfate activation technology, carbon dioxide capture, remediation of heavy metal and organic contaminants, volatile organic compound (VOC) adsorption, as well as electrochemical sensing devices. Existing research results demonstrate that modification strategies including metal and non-metal doping, surface oxidation treatment, and compounding with semiconductors or metal oxide materials can effectively improve the catalytic activity and functional performance of biochar. Furthermore, this paper prospects the future interdisciplinary development trends of biochar, analyzes the existing research gaps in mechanism exploration, structural optimization design, and industrial large-scale preparation, and provides theoretical and practical references for the further popularization and application of biochar in sustainable energy development and environmental governance fields. Full article

Heavy metal fluoride glasses (HMFGs), particularly fluorozirconate glass systems such as ZBLAN have attracted considerable attention due to their unique physical properties, including low phonon energies, wide transparency from the UV to the mid-IR, and high rare-earth ion doping solubility, making them promising materials for photonic applications. This review provides an overview of fluoride glass synthesis methods, structural characteristics, and physical properties of fluorozirconate glasses, with emphasis on glass processing conditions, thermal, mechanical, and optical properties. The structural characteristics are discussed in terms of zirconium–fluorine polyhedral networks and their compositional dependence, while physical properties are analyzed, including glass transition behavior, crystallization tendency, elastic moduli, and infrared transmission. Rare-earth doped Er³⁺, Ho³⁺, and Tm³⁺ ZBLAN glasses are also discussed, which exhibit efficient emissions in the near and mid-IR spectral regions. Although significant progress has been achieved, limitations related to thermal stability, mechanical strength, and incomplete understanding of structure–property relationships persist. Future research should therefore focus on compositional optimization and predictive structural modeling to enable the design of improved fluoride glasses for various applications. Full article

Additive manufacturing provides a fabrication route for electrode components with controlled macrostructure; however, printable carbon inks that also incorporate oxygen reduction reaction active precursors remain underdeveloped. Here, XC-72 carbon was combined with selected metal precursors to prepare N–C, Fe–N–C, and Pt-containing carbon ink formulations for direct ink writing. The precursor mixtures were incorporated into a polyurethane-based matrix, pyrolyzed at 900 °C, and characterized using X-ray diffraction, oscillatory rheology, rotating ring-disk electrode measurements, Brunauer–Emmett–Teller surface-area analysis, and scanning electron microscopy. XRD confirmed retention of carbon diffraction features and the formation of metal-containing crystalline phases after pyrolysis. Oscillatory rheology showed storage moduli exceeding loss moduli for the tested formulations, indicating elastic-dominant behavior suitable for shape retention during printing. For the PGM-free formulations, incorporation of nitrogen and iron precursors improved ORR onset potential, half-wave potential, limiting current density, and electron-transfer selectivity relative to the carbon control. BET analysis showed a decrease in accessible surface area after precursor incorporation, consistent with partial pore blocking or structural modification during pyrolysis. These results establish a printable formulation platform for ORR-active carbon-based inks, while future work is required to isolate the effects of printed architecture, pore hierarchy, and durability under fuel-cell operating conditions. Full article

Nitrites and nitrates are admitted into the body through the consumption of various foods, primarily cured meat products. These nitrites and nitrates are precursors of reactive nitrogen species NO and NO₂, which, in excess, promote nitrosative stress. Attempts have been made to combat oxidative and nitrosative stress through C₆₀ fullerenols in animal models. Furthermore, experimental and theoretical studies have shown that the use of carbon nanomaterials such as defective or doped graphene and C₆₀ metallofullerenes facilitates the capture of NO_x pollutants contained in the air. This leads us to propose that the inclusion of metals in C₆₀ fullerenols may have the potential to capture these reactive nitrogen species and be considered in nitrosative stress tests in animal models. Alternatively, viewed from another perspective, a certain grade of hydroxylation of metallofullerenes could enhance the capture of atmospheric nitrogen pollutants. Therefore, Li, Ca and Y metals were included in C₆₀ fullerenols at different coating grades. Using density functional theory (DFT), we analyzed the antiradical character of these metallofullerenols, and the adsorption energies of the free radicals (NO_x) were calculated to evaluate the ability of these metallofullerenols to adsorb these nitrogen species. Although both fullerenols and endohedral metallofullerenes have individually shown promise as radical scavengers, a systematic understanding of how the encapsulated metal and the grade of hydroxylation jointly govern the capture of nitrogen species is still lacking. In particular, it remains unclear whether increasing the number of hydroxyl groups monotonically enhances the capture capacity or whether optimal combinations of metal identity and surface functionalization exist. Addressing this gap is crucial, since excessive hydroxylation may alter the electronic structure, stability, and mechanism of interaction with NO_x radicals, potentially compromising capture capacity. Therefore, a rational evaluation that simultaneously considers electronic donor–acceptor properties, local reactivity, and adsorption thermodynamics is required to identify metallofullerenols with possible potential to sense or scavenge NO_x. Full article

Background: Carbamazepine (CBZ) and aripiprazole (ARI), frequently detected in medical facility effluents, are resistant to conventional wastewater treatment. However, a systematic comparison of their electrolytic degradation product profiles under different electrode conditions using an identical operating platform has not been previously reported. Methods: CBZ and ARI in NaCl solutions were subjected to electrolytic oxidation using the Eleca^® system with either a boron-doped diamond (BDD) or a metal electrode. Residual drugs were quantified by LC-MS/MS and pseudo-first-order degradation kinetics were calculated. Transformation products were characterized by LC/PDA/HRMS/MS based on accurate mass measurements, MS/MS fragmentation, chromatographic behavior, and UV absorption. Radical scavenger experiments using methanol and tert-butanol were conducted to investigate reactive species’ contributions to degradation. Results: Both drugs were rapidly degraded under all conditions, with the metal electrode consistently exhibiting higher apparent pseudo-first-order rate constants than the BDD electrode. The metal electrode generated hydrophobic intermediates apparently retaining aromatic skeletons (consistent with partial oxidation), whereas the BDD electrode yielded more polar, low-molecular-weight products consistent with more extensive skeletal fragmentation (deep oxidation). Scavenger experiments suggested a greater relative contribution of hydroxyl radicals (•OH) under BDD electrode conditions. Transformation products were transiently detected but eliminated by prolonged electrolysis. Conclusions: Electrode material critically determines the degradation pathway, reactive species distribution, and product profile. Structural analysis of the tentatively identified transformation products suggests loss of pharmacophore integrity in several intermediates; however, residual pharmacological risk has not been experimentally validated and requires biological sassays for confirmation. Furthermore, the observed disappearance of the parent compounds does not demonstrate complete mineralization, detoxification, or environmental safety, as total organic carbon measurements and ecotoxicological assays were not performed. This study provides the first comparative characterization of transformation products of recalcitrant psychotropic drugs under metal vs. BDD electrode electrolysis, offering mechanistic insights for pharmaceutical wastewater treatment optimization. Full article

Two-dimensional transition metal dichalcogenides (TMDCs) require highly controllable and scalable synthesis methods for successful integration into next-generation optoelectronic technologies. This study presents a modified two-step thermally assisted conversion approach for synthesizing 2D tungsten diselenide (WSe₂) by introducing an intermediate UV–ozone treatment. Magnetron-sputtered tungsten films are exposed to UV–ozone, converting the precursor into a uniform, dense layer of amorphous tungsten trioxide (WO₃) prior to the selenization process via chemical vapor deposition. X-ray photoelectron spectroscopy and Raman spectroscopy confirm the complete phase transition from the oxidized precursor to the 2H-WSe₂ crystal lattice. Morphological evaluations utilizing transmission electron microscopy and atomic force microscopy demonstrate that the ozonated precursors yield highly uniform, triangular flakes exceeding 5 µm in lateral size, effectively eliminating the unreacted WO₃ phases observed in untreated samples. Furthermore, the intermediate oxidation step finetunes the electronic band structure; the resulting WSe₂ exhibits an enhanced p-type character with a valence band maximum shift to 0.35 eV, a tuning attributed to residual oxygen doping. Optical characterizations reveal significantly improved transmittance in the visible spectrum, accompanied by excitonic absorption shifts indicative of reduced layer dimensionality. This intermediate ozonation strategy provides a highly effective pathway for producing high-quality WSe₂ nanosheets with tailored structural and optoelectronic properties. Full article

To clarify the role of metal dopants in low-temperature NH₃-SCR of NO, FeMnTiO_x catalysts were synthesized by coprecipitation and separately modified with Ce, Co, or W. The catalysts were evaluated for NO conversion, separate O₂/H₂O switching response and dry-feed time-on-stream stability and characterized by XRD, SEM, N₂ adsorption–desorption, XPS, H₂-TPR and NH₃-TPD. Ce doping at Ce/Mn = 0.3 suppressed TiO₂ crystallization, increased the BET surface area from 136 to 231 m² g⁻¹ and the pore volume from 0.19 to 0.58 cm³ g⁻¹, raised the Mn⁴⁺/Mn³⁺ ratio from 0.70 to 1.25, and increased the medium-strong-acid relative peak area from 555.4 to 1293.2 a.u. FeMnCe_0.3TiO_x maintained at least 90% NO conversion from 140 to 360 °C, gave 75% conversion at 400 °C, and averaged 97.4% during a 40 h dry-feed test at 350 °C. The results show that the superior Ce-modified catalyst arises from the combined regulation of texture, surface redox balance and acidity. Full article