Controlled establishment of advanced local high-entropy NiCoMnFe-based layered double hydroxide for zinc batteries and low-temperature supercapacitors.

The development of high-performance electrodes is essential for improving the charge storage performance of rechargeable devices. In this study, local high-entropy C, N co-doped NiCoMnFe-based layered double hydroxide (C/N-NiCoMnFe-LDH, C/N-NCMF) were designed using a novel method. Multi-component synergistic effects can dramatically modulate the surface electron density, crystalline structure, and band-gap of the electrode. Thus, the electrical conductivity, electron transfer, and affinity for the electrolyte can be optimized. Additionally, the C/N-NCMF yielded a high specific capacitance (1454F·g-1) at 1 A·g-1. The electrode also exhibited excellent cycling stability, with 62 % capacitance retention after 5000 cycles. Moreover, the assembled Zn||C/N-NCMF battery and the C/N-NCMF//AC hybrid supercapacitor yielded excellent energy densities of 63.1 and 35.4 Wh·kg-1 at power densities of 1000 and 825 W·kg-1, and superior cycling performance with 69 % and 88.7 % capacitance retention after 1000 and 30,000 cycles, respectively. Furthermore, the electrode maintained high electrochemical activity and stability and ensured high energy density, power density, and cycling stability of the rechargeable devices even at a low temperature (-20 °C). This study paves a new pathway for regulating the electrochemical performance of LDH-based electrodes.

Evolution of High-Index Facets Pt Nanocrystals Induced by N-Defective Sites in the Integrated Electrode for Enhanced Methanol Oxidation.

Highly efficient and durable Pt electrocatalysts are the key to boost the performance of fuel cells. The high-index facets (HIF) Pt nanocrystals are regarded as excellent catalytic activity and stability catalysts. However, nucleation, growth and evolution of high-index facets Pt nanocrystals induced by defective sites is still a challenge. In this work, tetrahexahedron (THH) and hexactahedron (HOH) Pt nanocrystals are synthesized, which are loaded on the nitrogen-doped reduced graphene oxide (N-rGO) support of the integrated electrodes by the square wave pulse method. Experimental investigations and density functional theory (DFT) calculations are conducted to analyze the growth and evolution mechanism of HIF Pt nanocrystals on the graphene-derived carbon supports. It shows that the H adsorption on the N-rGO/CFP support can induce evolution of Pt nanocrystals. Moreover, the N-defective sites on the surface of N-rGO can lead to a slower growth of Pt nanocrystals than that on the surface of reduced graphene oxide (rGO). Pt/N-rGO/CFP (20 min) shows the highest specific activity in methanol oxidation, which is 1.5 times higher than that of commercial Pt/C. This research paves the way on the design and synthesis of HIF Pt nanocrystal using graphene-derived carbon materials as substrates in the future.

Electrochemical Performance of Corn Waste Derived Carbon Electrodes Based on the Intrinsic Biomass Properties.

The exploration of cost-effective and sustainable biomass-derived carbon materials as electrodes for energy conversion and storage has gained extensive attention in recent research studies. However, the selection of the biomass and the electrochemical performance regulation of the derived biochar, as well as their interrelationship still remain challenging for practical application. Herein, corn wastes with high carbon content (>40%), corn cob and corn silk, were selected as precursors for the preparation of high value-added and high yield carbon materials via a modified synthetic process. Uniquely, this work put emphasis on the theoretical and experimental investigations of how the biomass properties influence the composition and nanostructure regulation, the electrolyte ion adsorption free energy, and the electrical conductivity of the derived carbon materials as well as their electrochemical performance optimization. Owing to the favorable specific surface area, the hierarchical porous structure, and the diverse elemental distribution, corn cob and corn silk derived carbon materials (CBC and SBC) present great potential as promising electrodes for alkaline aqueous zinc batteries and supercapacitors. The assembled CBC//Zn and SBC//Zn zinc batteries deliver high energy densities of 63.0 Wh kg-1 and 39.1 Wh kg-1 at a power density of 575 W kg-1, with excellent cycling performance of 91.1% and 84.3% capacitance retention after 10,000 cycles. As for the assembled symmetric supercapacitors, high energy densities of 14.9 Wh kg-1 and 13.6 Wh kg-1, and superior long-term cycling stability of 99.3% and 96.6% capacitance retention after 20,000 cycles could be achieved. This study highlights the advantages of utilizing corn cob and corn silk as carbon sources on the designed synthesis of carbon electrodes, and presents a meaningful perspective in the investigation of biomass-derived carbon materials and their potential applications in rechargeable devices.

Anti-inflammatory activity of different isolated sites of Chloranthus serratus in complete Freund's adjuvant-induced arthritic rats.

Chloranthus serratus is a traditional Chinese medicine for treating arthritis and bruises. The aim of the present study was to investigate the anti-arthritic activities and possible associated mechanisms of different isolated sites of Chloranthus serratus (DISC) in adjuvant-induced arthritis (AA) rats. The therapeutic effects of the extracts were assessed through changes in body weights, swelling rates, arthritis indexes (AI) and organ indexes. The levels of nitric oxide (NO), malondialdehyde and superoxide dismutase were determined using one-step method, TBA method and hydroxylamine method, respectively; the levels of TNF-α, IL-1ß, IL-6, prostaglandin E2, macrophage inhibitor factor-1, VEGF, immunoglobulin (Ig) G, IgM and IFN-γ in serum were determined using ELISA. Pathological changes and positive expression of VEGF in the ankle joints were investigated using hematoxylin-eosin staining and immunohistochemical staining, respectively. DISC treatment increased the weight gains and thymus indexes, and decreased the swelling rates, spleen indexes and AI in AA rats. The water isolated site (WA) and ethyl acetate isolated site (EA) significantly reversed complete Freund's adjuvant (CFA)-induced changes in the levels of NO, IL-6, TNF-α, IgG and IFN-γ, while the n-butanol isolated site (NB) only reversed the changes in IL-6 and IgG contents. Some changes in the chloroform isolated site group showed the same trend as those in the model group. The extracts relieved synovial hyperplasia, inflammatory cell infiltration and articular surface defects, and reduced the positive expression rate of VEGF in the synovial tissues of the AA rats to varying degrees. The WA exhibited the most marked effects, followed by the EA and NB, indicating that WA had optimal therapeutic effects on CFA-induced arthritic rats, which may be mediated by the oxidative stress and inhibition of inflammatory factors. C. serratus may serve as a potential candidate for the treatment of rheumatoid arthritis.

Fabrication of a near-infrared excitation surface molecular imprinting ratiometric fluorescent probe for sensitive and rapid detecting perfluorooctane sulfonate in complex matrix.

Construction of fluorescent probe for highly sensitive and selective detection of perfluorooctane sulfonate (PFOS) in water and biological samples is a very important strategy in related pollutant monitoring and environmental health risk appraisal. To overcome the drawback of low sensitivity caused by high-back ground signal of the conventional sensor, a molecularly imprinted near-infrared excitation ratiometric fluorescent probe was constructed and employed to determine PFOS. The sensing process was achieved through the selectively recognition of specific cavities in the probe surface with analyte, accompanied by fluorescence quenching due to the photoinduced electron transfer effect between upconversion materials and PFOS. Under optimized experimental conditions, the fluorescence quenching efficiency of the probe has good linearity against the concentrations of PFOS response divided into two segments within linear ranges of 0.001-0.1 nmol/L and 0.1-1 nmol/L, respectively, with low detection limit of 1 pmol/L. Selective experiment results indicate that the C-F chain length plays a dominant role in molecular recognition and high sensitively detection. The fabricated probe shows well detection performance in a wide pH range. Furthermore, real samples analyses indicate that such an efficient fluorescent probe has potentials in PFOS determination in surface water, human serum and egg extract sample analyses.

Selective extraction of perfluorooctane sulfonate in real samples by superparamagnetic nanospheres coated with a polydopamine-based molecularly imprinted polymer.

Superparamagnetic core-shell structured molecularly imprinted polydopamine nanospheres were constructed via self-polymerization of dopamine to attach the template onto the surface of magnetic Fe3 O4 substrate in tris-HCl solution. Then they were used for the specific recognition and extraction of perfluorooctane sulfonate from environmental water and human serum samples. The structural features and morphological characterization of the magnetic imprinting nanospheres were assessed, indicating that the magnetic polydopamine imprinted composite was successfully prepared and featured excellent magnetic separation characteristics. Adsorption experiments revealed that the magnetic adsorbents exhibited rapid adsorption kinetics and highly selective recognition properties toward perfluorooctane sulfonate. The stability and regeneration experiments indicated the materials had repeatable activity retention after repeated reuse. As a magnetic solid-phase extraction adsorbent, it was successfully applied for the extraction and quantification of perfluorooctane sulfonate in environmental water and human serum samples combined with liquid chromatography tandem mass spectrometry, with recoveries of ∼70-101.5% obtained in real samples. These results demonstrate that the prepared magnetic imprinting nanospheres are effective for the selective separation of perfluorooctane sulfonate from real samples. The synthesis technique is an effective and facile method that is conducted in aqueous solution and at ambient temperature, which is low cost, environmentally benign, and easy for scaling-up.

Oxidative stress-mediated hepatotoxicity in rats induced by ethanol extracts of different parts of Chloranthus serratus.

CONTEXT: Chloranthus serratus (Thunb.) Roem. et Schult. (Chloranthaceae) is an herb widely used as a folk medicine treating inflammatory diseases, although it is toxic. OBJECTIVE: To investigate hepatotoxicity and related mechanisms induced by ethanol extracts of different parts of C. serratus in rats. MATERIALS AND METHODS: Sprague Dawley rats were divided into control (Con), ethanol extract of roots (ER), stems (ES), and leaves (EL) groups, and acute oral toxicity studies were conducted. The rats received doses of 4.14, 3.20, and 1.16 g/kg/d extracts for 14 days, respectively. Liver index, liver function and oxidative stress biomarkers, liver pathology, ultrastructure, TNF-α, ICAM-1, and Nrf2/HO-1 proteins expression levels were determined. RESULTS: The LD50 of ER, ES, and EL were higher than 10.35, 8.05, and 2.90 g/kg/p.o., respectively. The liver indexes in the extract groups increased significantly. EL dramatically increased TP, GLB, AST, ALT, ALP, TBA, MDA, ICAM-1, and TNF-α levels (p < 0.01), and induced the most obvious pathological and ultrastructural changes. ES and EL obviously decreased the T-SOD, GSH, CAT, and CHOL levels. Nrf2 and HO-1 proteins expression was reduced significantly in ES (0.77 ± 0.06, 2.33 ± 0.20) and EL (0.23 ± 0.04, 2.14 ± 0.16) groups, and reduced slightly in ER (1.08 ± 0.10; 3.39 ± 0.21) group. DISCUSSION AND CONCLUSION: ES and EL induce stronger hepatotoxicity than ER through oxidative stress and the Nrf2/HO-1 pathway, and the root is a better medicinal part, which provides a basis for clinical research, safe applications, and reasonable development of C. serratus.

Transformation of cellulose and its derived carbohydrates into formic and lactic acids catalyzed by vanadyl cations.

The transformation of cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establish biomass-based sustainable chemical processes. The systems able to catalyze the conversion of cellulose into key chemicals in water without the consumption of hydrogen are limited. We report that simple vanadyl (VO(2+)) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water. We have discovered an interesting shift of the major product from formic acid to lactic acid on switching the reaction atmosphere from oxygen to nitrogen. Our studies suggest that VO(2+) catalyzes the isomerization of glucose to fructose, the retro-aldol fragmentation of fructose to two trioses, and the isomerization of trioses, which leads to the formation of lactic acid under anaerobic conditions. The oxidative cleavage of C-C bonds in the intermediates caused by the redox conversion of VO2(+)/VO(2+) under aerobic conditions results in formic acid and CO2. We demonstrate that the addition of an alcohol suppresses the formation of CO2 and enhances the formic acid yield significantly to 70-75 %.

Fe(3)O(4)-Au and Fe(2)O(3)-Au Hybrid Nanorods: Layer-by-Layer Assembly Synthesis and Their Magnetic and Optical Properties.

A layer-by-layer technique has been developed to synthesize FeOOH-Au hybrid nanorods that can be transformed into Fe(2)O(3)-Au and Fe(3)O(4)-Au hybrid nanorods via controllable annealing process. The homogenous deposition of Au nanoparticles onto the surface of FeOOH nanorods can be attributed to the strong electrostatic attraction between metal ions and polyelectrolyte-modified FeOOH nanorods. The annealing atmosphere controls the phase transformation from FeOOH-Au to Fe(3)O(4)-Au and α-Fe(2)O(3)-Au. Moreover, the magnetic and optical properties of as-synthesized Fe(2)O(3)-Au and Fe(3)O(4)-Au hybrid nanorods have been investigated.

Hydrothermal synthesis and photoluminescence of Eu(2-x)Sm(x)Sn2O7 (x = 0-2.0) nanophosphors.

Eu(2-x)Sm(x)Sn2O7 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0) solid solutions were successfully synthesized by a simple, mild hydrothermal process. The crystal structure, particle size, and chemical composition of the solid solutions were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction patterns and transmission electron microscopy images reveal that all the products were cubic pyrochlore-type Eu(2-x)Sm(x)Sn2O7 nanocrystals with the diameter of approximately 20 nm. Due to efficient energy transfer from Sm3+ to Eu3+, the Eu(2-x)Sm(x)Sn2O7 (x = 0.1, 0.5, 1.0, and 1.5) nanocrystals exhibited strong 5D0 --> 7F1 photoluminescence emission of Eu3+. The dominant 5D0 --> 7F1 transition revealed good monochromaticity and low distortion of the Eu(2-x)Sm(x)Sn2O7 nanophosphors.