Search Results (752)

Background: Perfluorooctane sulfonate (PFOS) is a globally recognised persistent, bioaccumulative and toxic pollutant. Under China GB 5749-2022 and the US EPA 2024 drinking water MCL, permissible levels have fallen to 40 ng L⁻¹ and 4 ng L⁻¹, respectively, placing unprecedented demands on remediation technologies. Methods: An iron(III)–carboxylate metal–organic framework prepared from low-cost precursors (denoted MOF-LC, [Fe₃O(BDC)₃Cl]·x(solvent)) was synthesised via a one-pot solvothermal route from FeCl₃·6H₂O and terephthalic acid (H₂BDC). The material was characterised by PXRD, N₂ adsorption, FTIR, TGA, XPS, elemental analysis and ICP-OES. Adsorption performance was evaluated under varying initial concentrations, contact times, pH values, coexisting inorganic anions (Cl⁻, NO₃⁻, SO₄²⁻, HCO₃⁻, PO₄³⁻) and humic acid backgrounds, and by a panel of six water matrices. Results: MOF-LC exhibited a BET surface area of 1528 m² g⁻¹ and a dominant pore centred at 1.9 nm, which is geometrically compatible with the 1.36 nm molecular length of PFOS. Adsorption reached ≈95% of equilibrium capacity within 30 min and was best described by the pseudo-second-order model (R² = 0.998). Measured uptake reached 800.6 mg g⁻¹ at 298 K, corresponding to a Langmuir maximum capacity of 802 mg g⁻¹ (note that all adsorption experiments were conducted at mg L⁻¹ concentrations, several orders of magnitude above the regulatory limits cited above). Removal exceeded 88% across all six water matrices. PFOS removal efficiency fell from 99.2% to 85.8% over seven adsorption–regeneration cycles using a 1% NH₄Cl/methanol eluent, with 90.6% of the initial BET surface area retained and Fe leaching below 45 µg L⁻¹. Conclusions: Electrostatic, hydrophobic and pore confinement contributions are proposed as cooperative interpretations consistent with the observations. MOF-LC is identified as a technically promising laboratory-scale sorbent for PFOS removal from complex water matrices. Performance at environmentally relevant ng L⁻¹ concentrations and economic viability at scale remain to be established. Full article

The continuous release of pharmaceutical contaminants such as naproxen (NPX) into aquatic environments poses substantial ecological risks. In this study, a series of visible-light-responsive bismuth oxychloride-iodide (BiOCl_xI_1−x) solid solutions were synthesized via a simple one-step solvothermal method. XRD analysis confirmed the formation of a tetragonal matlockite-type solid solution, while SEM and TEM observations revealed three-dimensional flower-like hierarchical microspheres assembled from ultrathin nanosheets. Among the prepared samples, BiOCl_0.3I_0.7 exhibited the highest visible-light photocatalytic activity toward NPX degradation, achieving a removal efficiency of 87% within 60 min. Its apparent pseudo-first-order rate constant was 0.0740 min⁻¹, the highest among the investigated compositions. Experimental measurements showed composition-dependent band-gap narrowing, while representative DFT calculations indicated that I-for-Cl substitution modifies the valence-band electronic states, providing a qualitative electronic-structure explanation for the enhanced visible-light response. Evaluation of operational parameters showed that NPX degradation was favored at lower initial NPX concentrations and under acidic conditions, whereas humic acid and bicarbonate (HCO₃⁻) inhibited the process. TOC analysis further confirmed partial mineralization of NPX during photocatalysis. Electron paramagnetic resonance (EPR) analysis and reactive-species trapping experiments indicated that photogenerated holes (h⁺), singlet oxygen (¹O₂), and superoxide radicals (O₂^•−) were the dominant reactive species involved in NPX degradation. These findings demonstrate the potential of band-gap-engineered bismuth-based solid solutions for environmental remediation. Full article

Magnetic heterogeneous Fenton Fe₃O₄/HNT catalysts were successfully synthesized using the solvothermal method. Characterization of Fe₃O₄/HNT composites involved XRD, XPS, FT-IR, SEM, BET and TEM. Results showed uniform anchoring of magnetic Fe₃O₄ nanoparticles on HNTs’ external surface. Under pH conditions close to neutral, the catalyst achieved a naphthalene (NAP) removal efficiency exceeding 98% within 15 min while maintaining a relatively high H₂O₂ utilization rate. The catalyst exhibits significant resistance to common aqueous interferers containing anions (NO₃⁻, Cl⁻, CO₃²⁻) and humic acids. Moreover, the catalyst could be easily isolated from the solution through the use of magnetic separation technology. It displayed remarkable stability and recyclability, maintaining NAP removal efficiency above 80% even after the fifth cycle, in comparison to the initial catalyst. The excellent catalytic performance of this catalyst is attributed to the synergistic effect between HNT and Fe₃O₄. Meanwhile, the diverse Fenton catalytic process of Fe₃O₄/HNT was explained, indicating that hydroxyl radicals (•OH) and superoxide anion radicals (•O₂⁻) were key in eliminating NAP in the Fe₃O₄/HNT-H₂O₂ setup. Full article

In this study, a hierarchical rod-assembled, polypyrrole-modified Ce–Al–La trimetallic metal–organic framework (Ce–Al–La–MOFs@PPy) composite was successfully synthesized through a solvothermal method combined with in situ polymerization for efficient fluoride removal from aqueous solutions. The incorporation of conductive polypyrrole (PPy) into the multimetallic MOFs effectively enhanced the structural stability, surface properties, and adsorption performance of the material. Adsorption experiments demonstrated that the optimal metal-to-ligand molar ratio was 3:1, and the prepared adsorbent exhibited excellent fluoride removal performance under weakly acidic conditions (pH = 5). The maximum adsorption capacity calculated from the Langmuir model reached 216.92 mg·g⁻¹ at 45 °C. Adsorption kinetics were well fitted by the pseudo-second-order model, indicating that the adsorption process was mainly governed by chemisorption. Mechanism investigations based on FTIR and XPS analyses demonstrated that fluoride removal mainly occurred through electrostatic attraction and coordination exchange between fluoride ions and the Ce/La active sites. In addition, the composite exhibited good selectivity, anti-interference ability toward coexisting ions, and satisfactory fluoride removal performance in practical industrial wastewater. These findings suggest that Ce–Al–La–MOFs@PPy is a promising adsorbent for efficient fluoride-contaminated wastewater treatment. Full article

Niobium-based catalysts have emerged as highly adaptable materials for reactions under heterogeneous conditions, owing to significant advances achieved in synthetic methodologies and characterization strategies. In this review, special attention was paid to analyzing the main methods used to characterize the physicochemical properties (e.g., gas adsorption/desorption, infrared spectroscopy, X-ray diffraction patterns, and temperature-programmed desorption) of solid niobium catalysts, as well as the most widely used and versatile synthesis methods (e.g., microwave-assisted solvothermal synthesis, impregnation, and mechanical milling). These insights can facilitate the rational design of Nb-based catalysts to achieve high activity and selectivity in biomass conversion processes and the valorization of biomass-derived compounds. The developments outlined here underscore the adaptability of niobium materials and provide a comprehensive basis for understanding the relationships between synthesis methodology and physicochemical properties, thereby supporting the development of more efficient Nb-based catalysts for sustainable catalytic applications. Full article

Metal–organic frameworks (MOFs) based on triazole have attracted considerable interest as promising porous materials for CO₂ capture due to their high surface area, ultramicroporosity, and excellent thermal and chemical stability. Nitrogen-rich triazole ligands contain abundant Lewis basic sites that promote CO₂ adsorption via dipole–quadrupole interactions, hydrogen bonding and cooperative interactions with open metal sites. The present review discusses recent developments in the synthesis of triazole-based MOFs, with special emphasis on the relation between structural features and CO₂ adsorption performance. The paper reviews different synthetic routes such as solvothermal, hydrothermal, mechanochemical and post-synthetic modification methods and their impact on crystallinity, porosity and scalability. The roles of metal centres, pore confinement and linker functionalization in tuning CO₂ uptake, selectivity and adsorption energetics are highlighted. Moreover, the mixed-linker strategies and defect engineering are explored to illustrate the use of the synergistic effect of nitrogen-rich sites and metal nodes for the improvement of the adsorption performance. Still, a number of challenges remain such as achieving an optimal balance between adsorption strength and regenerability, increasing stability in humid and realistic flue-gas conditions, and the development of scalable and sustainable synthesis routes. In summary, triazole-based MOFs provide a versatile platform for the design of high-performance CO₂ adsorbents by combining structural robustness with chemically active, nitrogen-rich adsorption environments. Full article

Lithium-ion batteries (LIBs) are essential for current technological infrastructure, driving the development of portable electronics, electric vehicles or grid-scale energy storage. The performance and sustainability of LIBs are critically dependent on their anode materials. This comprehensive review analyzes the evolution and characteristics of key anode materials, highlighting the specific properties they confer to the final battery products. Beyond material properties, the synthesis methods employed for these materials, from conventional techniques (such as solid-state reactions, sol–gel, hydrothermal/solvothermal, co-precipitation, etc.) to innovative and greener approaches (like electrospinning and a novel induction furnace-oxidation hybrid method for complex oxides), are a crucial part in the development of sustainable materials. While these methods offer different advantages, the challenges in achieving optimal electrochemical performance, including issues related to material stability, capacity retention and scalability, remain significant for both research and manufacturing industries. Furthermore, a significant focus is placed on strategies for mitigating the environmental impact associated with anode material production, emphasizing the importance of unconventional and sustainable synthesis routes. Ultimately, the sustainable evolution of LIB technology to achieve future energy demands hinges on overcoming existing limitations. This necessitates integrated research combining advanced material modeling and design, scalable and environmentally conscious synthesis techniques and in-depth electrochemical characterization. Full article

Metal oxide nanoparticles have been the subject of intense research interest because of their remarkable physicochemical properties, such as their high surface area, particle size tunability, outstanding chemical stability, optical activity, catalytic efficiency, and antimicrobial behavior. These properties make them very useful in environmental, biomedical, energy, sensing, agricultural and industrial applications. The chosen synthesis method is important in controlling the morphology, crystallinity, surface charge, band gap and overall performance of metal oxide nanoparticles. They have been prepared using various physical, chemical and biological means, such as sol–gel, co-precipitation, hydro/solvothermal, microwave-assisted, sonochemical, combustion and green synthesis. Of these, green synthesis is gaining more interest as it employs plant extracts, microorganisms, and other biological materials as reducing agents, stabilizing and capping agents that make the process more eco-friendly and cost-effective. Recent advancements in the synthesis and application of metal oxide nanoparticles are discussed. There is an emphasis on the major synthesis routes, the main factors that influence the formation of nanoparticles, the characterization techniques used, and the structure–property relationships uncovered. A special focus is given to the influence of synthesis parameters, such as the type of precursor and the pH, temperature, reaction time, solvents and capping agents, on the properties of nanoparticles. In addition, the uses of metal oxide nanoparticles in photocatalysis, wastewater treatment, antimicrobial activity, drug delivery, biosensing, energy storage, gas sensing, and agriculture are also included. Finally, present challenges, toxicity issues, the problems of large-scale production, and future research directions are discussed to support the practical and sustainable uses of metal oxide nanoparticles. Full article

For efficient alkaline water-splitting, it is crucial to have bifunctional electrocatalysts that exhibit low overpotentials, durability, and the possibility of being produced through scalable methods. This study involved the use of screen printing to apply a porous nickel microparticle/polymer interlayer onto commercial nickel foam, which then acted as a base for the solvothermal growth of cobalt-based oxide/hydroxide nanostructures. The optimized electrode showed excellent bifunctional capabilities in 1 M KOH, requiring only 61 mV for the hydrogen evolution reaction and 241 mV for the oxygen evolution reaction at a current density of 10 mA cm⁻². In comparison, the control electrodes, such as those with cobalt directly deposited on unmodified nickel foam and screen-printed nickel foam substrates without cobalt, exhibited poorer overall performance. Although the cobalt-modified nickel foam exhibited a higher C_dl-derived apparent electrochemical surface area, the cobalt-modified screen-printed electrode achieved the best ECSA-normalized HER and OER responses, indicating that the enhancement in activity was not solely due to the capacitive surface area of the electrode. The increased integrated redox charge suggests a greater contribution from electrochemically accessible Co/Ni redox-active species, while impedance analysis supports a more favorable apparent interfacial response under the tested HER- and OER-relevant conditions. Long-term chronopotentiometry and post-stability SEM confirmed stable bifunctional operation. Full article

The development of cost-effective, efficient, and visible-light-responsive photocatalysts for hydrogen evolution is pivotal for addressing global energy shortages and environmental degradation. In this context, non-precious metal cocatalysts have garnered significant attention for modifying semiconductor photocatalysts. Herein, a high-performance Co_0.85Se/g-C₃N₄ composite photocatalyst was successfully synthesized via a facile solvothermal method, where transition metal Co_0.85Se nanoparticles were grown on g-C₃N₄ nanosheets in situ. The optimized 6-Co_0.85Se/g-C₃N₄ composite exhibited a superior photocatalytic hydrogen evolution rate of 426 µmol·g⁻¹·h⁻¹ under visible light irradiation, which is approximately 53 times higher than that of pristine g-C₃N₄. Experimental characterizations revealed that the Co_0.85Se nanoparticles were well dispersed on the g-C₃N₄ nanosheets without obvious agglomeration, which significantly broadened the visible-light absorption range of the composite. Furthermore, photoelectrochemical measurements confirmed that the Co_0.85Se cocatalyst effectively accelerated charge separation and migration kinetics. Consequently, the construction of this heterojunction endows the composite with excellent photocatalytic performance. This work offers new insights into the design of efficient, non-precious metal-based photocatalysts for sustainable hydrogen production. Full article

Tetracycline hydrochloride (TCH) contamination poses serious environmental risks due to its persistence and bioaccumulation. Here we present an oxygen-vacancy-enriched BiVO₄/TiO₂ S-scheme heterojunction (5% BVO/TO) synthesized via a one-step solvothermal method. Under visible light (λ  >  420 nm), this composite achieves 78.8% TCH degradation in 80 min, outperforming TiO₂ (69.5%) and BiVO₄ (34.1%). Its rate constant (0.0198 min⁻¹) is 1.4 and 4.0 times higher than TiO₂ and BiVO₄, respectively, while retaining over 70% activity after four cycles. XPS and EPR confirm that oxygen vacancies serve as electron traps to suppress recombination, and UPS combined with DFT calculations validates directional electron transfer from BiVO₄ to TiO₂. Radical scavenging tests and in situ EPR reveal h⁺ > •OH > •O₂⁻ as the dominant reactive species. This study offers a robust design strategy for OV-enhanced S-scheme photocatalysts toward efficient, sustainable degradation of antibiotic pollutants. Full article

This study examines the effect of annealing on 135 nm Fe₃O₄ nanospheres and establishes a direct correlation among particle shape, crystallite size, and magnetic properties. Polycrystalline nanospheres and highly crystalline nanocubes with an equivalent diameter/body diagonal of 135 nm were synthesized via solvothermal and thermal decomposition methods, respectively. Scanning electron microscopy (SEM) revealed that the nanospheres developed smoother surfaces and gradually transformed toward a cubic morphology upon annealing, with increasing temperature and duration. Vibrating sample magnetometry (VSM) measurements showed that both saturation magnetization and coercivity increased with annealing as the particles evolved toward cube-like morphology and larger crystallite size, indicating that the magnetic properties of Fe₃O₄ nanoparticles are strongly dependent on crystallite size and shape. Nanospheres annealed between 500 and 850 °C exhibited increases in both crystallite size and saturation magnetization; however, coercivity decreased at 850 °C, where the crystallite size was maximal. Annealing at 700 °C for 12 h resulted in enhanced crystallite size and improved magnetic properties. Prolonged annealing at 700 °C (24 h) yielded the largest crystallite size but led to a significant reduction in saturation magnetization. This study demonstrates a clear correlation between magnetic properties, crystallinity, and morphology in nanoparticles beyond the superparamagnetic size regime (e.g., 135 nm). It further provides a strategy for tuning structural parameters that govern magnetic behavior and establishes an alternative, more facile route to obtain Fe₃O₄ nanospheres with crystallite sizes and magnetic properties comparable to nanocubes obtained via direct synthesis. Full article

Solar-driven photocatalysis has attracted increasing interest as an efficient and environmentally friendly approach for the mineralization of pollutants. In this work, carbon-doped g-C₃N₄/V_oBiOBr composites rich in oxygen vacancy (denoted as CCN/V_oBOB) were prepared by combining calcination with a solvothermal method, using glucose as the carbon source. The obtained composites were comprehensively characterized by XRD, TEM, and XPS to investigate their crystal structure, morphology, and surface chemical states, and their photocatalytic activity was evaluated through the degradation of organic pollutants. Among the prepared samples, 3.2 wt% CCN/V_oBOB exhibited the best photocatalytic performance, reaching 98% degradation of Rhodamine B (RhB) and 95% degradation of Methylene Blue (MB) within 90 min, which was significantly superior to that of V_oBOB and g-C₃N₄/V_oBOB. This enhanced activity can be attributed mainly to the synergistic effects of oxygen vacancy, carbon doping, and heterojunction construction. Their combined action not only regulates the band structure of V_oBOB effectively, but also greatly inhibits the recombination of photogenerated electron–hole pairs. These results were further supported by UV-Vis DRS and transient photocurrent measurements. Radical trapping experiments indicated that superoxide radicals (O₂⁻) were the dominant active species during the reaction. In addition, density functional theory (DFT) calculations provided further evidence for the above conclusions. On the basis of both experimental observations and theoretical analysis, a reasonable photocatalytic reaction mechanism was proposed. This work offers a useful strategy for designing highly efficient photocatalysts through the synergistic integration of oxygen vacancy, nonmetal doping, and heterojunction engineering, and thus promotes the application of photocatalytic technology in pollutant degradation. Full article

In this study, response surface methodology (RSM) was employed to evaluate and optimize the key parameters for the solvothermal synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles, including solvent type, reaction temperature, reaction time, and material ratio. A multivariate regression model identified the optimal preparation conditions as ethanol as the solvent, a reaction temperature of 120 °C, a reaction time of 4 h, and a 5:1 molar ratio of 2-methylimidazole to zinc acetate. The resulting ZIF-8 nanoparticles exhibited highly selective adsorption capacity toward anthraquinones and were successfully applied to the rapid extraction and detection of five anthraquinones from Cassiae semen. By investigating the adsorbent dosage, adsorption efficiency, elution solvent, and elution efficiency, we established the optimal experimental conditions. Briefly, 20 mg of ZIF-8 nanoparticles were added to 10 mL of Cassia semen extract, and the mixture was shaken for 10 min before centrifugation. The residual anthraquinones in the supernatant were quantified by Ultra Performance Liquid Chromatography (UPLC). The adsorption efficiencies of aloe-emodin, rhein, emodin, chrysophanol, and physcion were 80.2%, 93.8%, 100%, 100%, and 100%, respectively. When eluted with methanol/100 mM NaHCO₃ solution (1:1, v/v), the corresponding elution efficiencies of these compounds were 82.8%, 97.8%, 85.1%, 93.2%, and 65.3%, respectively. The relative standard deviations (RSDs) for method precision, stability, and repeatability were all below 4.0%. The prepared ZIF-8 nanoparticles showed favorable adsorption performance toward the five anthraquinone components. The method is simple to operate, requires minimal sample and solvent consumption, and can be used for rapid extraction and detection of anthraquinones in traditional Chinese medicinal materials such as Cassiae semen. This work provides a scientific reference for the application of MOFs nanomaterials in food safety inspection and quality control of traditional Chinese medicinal materials. Full article

Nanostructured catalysts have become a core component of energy conversion in electrocatalysis and photocatalysis; however, successfully translating their performance from laboratory scale to industrial applications remains a long-standing challenge. This paper provides a critical assessment of the field, systematically tracing the entire development trajectory from catalyst design to practical application. We focus on five major classes of catalysts—monometallic catalysts, bimetallic/multimetallic alloy catalysts, metal compound catalysts, carbon-based composite catalysts, and single-atom catalysts—and explore synthetic strategies for achieving precise structural control, including hydrothermal/solvothermal methods, electrodeposition, template-assisted and MOF-derived syntheses, high-temperature pyrolysis, and post-treatment defect engineering. This paper delves into the mechanisms and performance descriptors governing the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), urea oxidation, photocatalytic water splitting, and CO₂ reduction. Based on the above analysis, this paper lays the mechanistic foundation for five core strategies to improve catalyst performance: morphology control, elemental doping, heterostructure and interface engineering, defect and vacancy engineering, and support modification. Furthermore, this paper provides an in-depth evaluation of the applications of these catalysts in water splitting, CO₂ valorization, fuel cells, metal–air batteries, and energy-saving electrolysis, with a particular focus on earth-abundant alternatives to precious metals. We argue that in many well-studied reactions, intrinsic activity may no longer be the primary bottleneck restricting their development; instead, the core challenge now lies in maintaining excellent catalytic performance under harsh and industrially relevant conditions, especially under high-current densities, impurity-containing feed systems, and long-term operating conditions. In response to this shift in research focus, this paper clearly identifies the key obstacles hindering the industrial application of catalysts and proposes practical directions for future research. Full article