RSC Advances最新文献

This study investigates the catalytic hydrothermal conversion of heterogeneous end-of-life automotive shredder residues (ASR) waste in near-supercritical water, focusing on process optimization, thermodynamic behavior, and multi-phase product characterization. Factorial screening identified temperature and residence time as critical parameters, with 350 °C and 90 minutes yielding maximum hydrochar through enhanced carbonization and repolymerization, accompanied by reduced liquid yields and CO₂-rich gas production. Thermodynamic analysis revealed significant increases in water ionization constant (K _w) during non-isothermal heating, peaking at 1.44 × 10^-12 mol² kg^-2 at 350 °C, while density decreased to 0.619 g cm^-3 under autogenous pressure. Isothermal reactions at 350 °C exhibited highly exothermic behavior (ΔH ≈ -143 kJ mol^-1) and strong ordering effects, correlating with peak hydrochar and gas yields. Catalyst screening demonstrated Ni-based catalysts' superior selectivity for phenolics and aromatic amines in the oil-phase, increased aqueous-phase total organic carbon, and minimized tar formation. Ru/Al₂O₃ favored ketone production, while non-catalyzed runs produced a broad range of C₆-C₂₉ oil products and 341 g (CO₂)/kg(feed) as the only gas product. The optimized NiSiAl catalyst yielded a maximum hydrochar of 64.4 wt% with enhanced thermal stability (onset degradation ∼425 °C), higher calorific values at 5 wt% feedstock concentration and feedstock-to-catalyst ratio of 9. The highest H₂ production (5 g kg^-1 feed) occurred at a catalyst ratio of 5, while the best liquid yield (36%) was achieved at the lowest ratio of 1. The GC-MS analysis revealed feedstock concentration influenced reaction pathways, shifting from phenolics and amines at low solids loading to hydrocarbons and ketones at higher concentrations. These findings highlight catalytic hydrothermal conversion as a viable circular-economy route for ASR valorization, combining thermodynamic efficiency with targeted fuel and chemical production.

Vanadium dioxide (VO₂) is a promising material for mid-infrared optical modulation due to its reversible metal-insulator transition. This study presents an efficient and stable method for fabricating VO₂ thin films with enhanced optical limiting performance via crystallinity control and microstructural optimization. The process combines magnetron sputtering with gradient annealing, and the effects of annealing temperature on film structure and optical properties were analyzed using X-ray diffraction, X-ray spectroscopy, and SEM. Annealing at 550 °C yielded high-quality monoclinic VO₂(M₁) films with excellent crystallinity, low defect density, and island-like grains (250-300 nm). The optimized film showed reduced oxygen vacancies (17.3%) and increased V⁴⁺ content. Optical measurements revealed strong thermal switching: mid-infrared transmittance dropped from 85% at 25 °C to 35% at 80 °C, achieving a 50% modulation depth-12.5-fold higher than that of unannealed films. Under 3.8 µm laser irradiation, modulation depth tripled. The annealing process effectively improved phase purity and reduced defects by encouraging grain growth and oxygen vacancy repair. This work provides key insights into the structure-defect-property relationships in VO₂ and offers a scalable route for producing high-performance phase-change oxide thin films.

¹⁷O Nuclear Magnetic Resonance (NMR) spectroscopy has become an increasingly valuable technique for investigating the structure, dynamics, and reactivity of polyoxometalates (POMs), a diverse class of metal-oxygen clusters with broad applications in catalysis, energy storage, and materials science. The oxygen framework of POMs plays a very important role in dictating their physical and chemical properties, making direct probing of oxygen environments essential. However, the quadrupolar nature and low natural abundance (0.037%) of ¹⁷O nuclei impose significant experimental challenges, including low sensitivity and broad line shapes. Recent methodological breakthroughs such as the development of ultra-high-field NMR instrumentation, the use of magic angle spinning (MAS) to minimize anisotropic broadening, and the implementation of dynamic nuclear polarisation (DNP) to boost signal intensity have greatly enhanced the resolution and feasibility of ¹⁷O NMR studies. These advances now enable the differentiation of terminal, bridging, and internal oxygen sites, offering unique insights into structural isomerism, substitution effects, and protonation states in various POM archetypes including Lindqvist, Keggin, and Dawson structures. Beyond structural assignments, ¹⁷O NMR has provided mechanistic understanding of catalytic processes by tracking oxygen participation in redox transformations and proton-coupled electron transfer. When integrated with computational approaches such as density functional theory (DFT) and artificial intelligence (AI), ¹⁷O NMR delivers predictive power for interpreting chemical shifts, quadrupolar parameters, and dynamic behaviour. This review consolidates recent progress, highlights case studies, and underscores the emerging role of ¹⁷O NMR as a cornerstone for advancing POM chemistry at the interface of structural science, catalysis, and theoretical modeling.

The sustainable conversion of lignocellulosic residues into renewable fuels and chemicals is vital to advancing a circular bioeconomy. This study presents a dual-scale thermochemical framework for the valorisation of pine needles (PN) and cashewnut shells (CNS) through integrated analytical and pilot-scale pyrolysis. Analytical pyrolysis using Py-GC/MS was employed to evaluate the temperature-dependent formation of bio-volatiles between 400 and 800 °C, revealing that 500 °C yielded the highest fraction of desirable compounds. PN generated aromatic-rich volatiles suitable for advanced fuel formulations, while cashewnut shells produced phenolic-rich vapours with applications in the renewable chemicals sector. The scale-up experiments conducted in a semi-pilot rotary kiln reactor confirmed the reproducibility of product yields and compositional trends observed at the laboratory scale. The maximum pyrolysis oil yields reached 40% for PN and 33% for CNS, while char and gas yields varied according to lignocellulosic composition. The elemental analysis indicated superior fuel quality for PN-derived bio-oil (higher heating value (HHV) = 35.08 MJ kg^-1, O/C = 0.23) compared with CNS oil (HHV = 28.14 MJ kg^-1, O/C = 0.43). Furthermore, biochars exhibited porous morphologies, indicating potential for environmental applications. This dual-scale methodology effectively bridges mechanistic understanding with process scalability, enabling tailored valorisation routes for underutilised biomass residues.

Herein we report the self-powered biosensor for detection of dissolved oxygen (DO) detection using a paper-based enzymatic biofuel cell (BFC) employing screen-printed electrodes composed of MgO-templated mesoporous carbon (MgOC). The sensor used an anode modified by flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) and a cathode modified by bilirubin oxidase (BOD) to enable selective oxygen reduction under glucose-rich conditions. Electrochemical analyses revealed a linear relationship between the cathodic current and DO concentration over the range of 0-22 mg L^-1, with a maximum power output of 398 µW cm^-2 at 20 mg L^-1 DO. The biosensor system was successfully used to quantify DO in both pure water and a commercial soft drink, without requiring external power sources. These findings demonstrate the feasibility of low-cost, disposable, and scalable DO sensing by using cathode-targeting enzymatic BFCs, thereby opening new avenues for environmental and food quality monitoring.

In the present study, biodegradable polyvinyl alcohol/graphene oxide-based thin films were prepared as a topical drug delivery system via the solvent casting method for the loading and controlled release of the antibacterial drug cephalexin. Results showed that all the fabricated thin films had highly uniform and smooth-surface textures. The chemical structure and crystallinity of the samples were investigated by FTIR spectroscopy and XRD analysis, and the SEM and EDX techniques revealed the successful loading and uniform dispersion of cephalexin within the prepared films. Investigations on the thermal properties of the samples indicated that the thermal stability of the samples increased with the addition of graphene oxide, while it decreased with the addition of cephalexin. Water contact angle measurements revealed an increase in the hydrophobicity of thin films upon the addition of graphene oxide and cephalexin, and the final scaffolds displayed a contact angle of 104.6° ± 1.72°. The fabricated thin films also displayed pH-dependent degradation, swelling, and release behaviors in PBS solutions of pH 7.4 and 5.5. Moreover, a two-stage release profile was observed for drug-containing films during the liberation of cephalexin into release media. Additionally, the drug-containing films exhibited potent antibacterial activity against both Gram-positive and Gram-negative bacteria. Evaluating the cytocompatibility of the samples revealed desired cell viability up to 64 mg mL^-1 during 24 h, and the toxic effect of the samples was increased in a concentration-dependent manner.

To address the growing demand for advanced oil-control materials in cosmetics, this study developed novel flower-like mesoporous silica nanoparticles (FLS) with topology-enhanced oil-adsorption properties. Using a biphasic microemulsion synthesis strategy, FLS with petal-like surface topology, radial pore channels, and excellent colloidal stability were successfully prepared. Compared with conventional mesoporous silica nanoparticles (MSN) with small mesopores (2-3 nm) synthesized via the classical Stöber method, FLS exhibited significantly superior oil-absorption capacity across a wide range of oils, with maximum uptake nearly twice that of MSN. Notably, FLS showed exceptional adsorption efficiency for large-molecular-weight oils, demonstrating an approximately 226.3% increase over MSN in adsorbing PDMS-15000 w. This remarkable enhancement is attributed to the unique flower-like topology, which provides large open concave structures for instantaneous oil wetting and straight, radially aligned mesochannels for rapid oil transport and maximized pore utilization. In vivo human skin tests further confirmed the cosmetic efficacy of FLS. Collectively, these findings position FLS as a next-generation oil-control material and highlight topology-enhanced oil adsorption as a novel design strategy for advanced adsorbents.

High acidity is a major challenge in producing high-quality fruit wines, particularly those derived from Prunus mume (greengage). This study investigated the physicochemical properties, organic acids, and flavor profiles of high-acidity greengage wines fermented by four Saccharomyces yeasts, followed by coculture fermentation with Torulaspora delbrueckii to evaluate flavor modification. Among the single cultures, ScBV818 exhibited the strongest fermentation capacity, achieving an alcohol content of 13.27%, total acidity of 54.55 g L^-1, and significantly enhanced levels of esters, aldehydes, and ketones. Its OAVs of ethyl hexanoate, ethyl octanoate, ethyl benzoate, methyl salicylate, and isoamyl acetate were the highest, contributing to rich fruity and floral aromas. Coculture fermentation further improved flavor complexity, with simultaneous inoculation of ScBV818 and T. delbrueckii increasing acetate and ethyl ester contents by 1124.09% and 29.06%, respectively, while enhancing OAVs of ethyl hexanoate, ethyl octanoate, eugenol, linalool, and α-terpineol. Mantel and RDA analyses revealed that high levels of organic acids, such as citric acid and l-malic acid, negatively correlated with acetate and ethyl ester synthesis, while positively influencing ketones, eugenol, and terpenes. These findings highlight the potential of tailored fermentation strategies, such as sequential or simultaneous inoculation, to optimize flavor profiles and sensory quality in high-acidity fruit wines.

α-Dystroglycan (α-DG) is an important component of the extracellular domain of the dystrophin complex, with extensive and diverse O-mannosylation modifications, which can widely participate in various physiological and pathological processes. In particular, core M1, core M2, and core M3 O-mannose glycans, which are post-translational modifications of α-DG, are shown to play critical roles in muscle and brain development. However, elucidating their precise mechanisms has been hampered by inherent structural heterogeneity, creating an urgent demand for efficient methods to obtain homogeneous glycans. Despite their structural complexity, tremendous progress has been made in the synthesis of O-mannose glycans and glycopeptides in recent years. By systematically comparing synthetic strategies and methodologies, this review highlights recent progress in the chemical, enzymatic, and chemoenzymatic synthesis of the three major O-mannose glycan types of α-DG. In addition, key synthetic challenges, including stereoselective glycosylation, site-specific functionalization, and scalability, are discussed. Finally, current limitations and future perspectives in O-mannose glycans synthesis are outlined, aiming to inspire further methodological innovation and biological applications.

Elemental mercury (Hg⁰) emission from coal combustion flue gas poses significant environmental and health risks due to its high volatility, persistence, and toxicity. In this study, a novel ternary BiOI-MnO_x-TiO₂ (BiMnTi) composite catalyst was successfully synthesized via a simple three-step method for efficient Hg⁰ removal under dark conditions. The composite catalysts were characterized by SEM-EDS, HRTEM, XRD, H₂-TPR, N₂ adsorption–desorption, FTIR, XPS, and EPR. The BiOI-MnO_x-TiO₂ composite exhibited superior Hg⁰ removal efficiency (>97%) over a wide temperature range of 50–200 °C, and showed excellent resistance to SO₂ and NO poisoning. Characterization results confirmed that the introduction of BiOI effectively increased the proportion of Mn⁴⁺ content and surface chemisorbed oxygen (O_β) and promoted the formation of oxygen vacancies. XPS and H₂-TPR analyses further demonstrated enhanced electron transfer between BiOI and MnO_x-TiO₂, as well as improved redox properties. Mechanistic studies revealed that the synergistic interaction between BiOI and MnO_x-TiO₂ facilitated electron transfer at the interface, promoting the oxidation of I⁻ to active iodine species, which subsequently reacted with adsorbed Hg⁰ to form stable HgI₂. This work provides a promising strategy for designing efficient and sulfur-resistant catalysts for Hg⁰ removal in non-photocatalytic environments.