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1.
Angew Chem Int Ed Engl ; 62(10): e202219214, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36625251

RESUMO

The nitrogen-deficient graphitic carbon nitride (g-C3 N4 ) has been prepared, a new excited state absorption (ESA) up-conversion mode is discovered, which is directly induced by structural defects, showing distinct chemical characteristics from those based on lanthanide ions and triplet states chromophores. The abundant N2C vacancies in g-C3 N4 nanosheets work as the crucial intermediate excitation states, which lead to g-C3 N4 upconverted emitting at the wavelength of 436 nm excited by the light with the wavelength of 800 nm. This process is proven to proceed via a two-photon involved ESA mode with a breakthrough quantum efficiency of 0.64 %. Further, we combine N2C vacancies enriched g-C3 N4 with In2 S3 and CdS, and successfully achieved an infrared light driven photocatalytic reactions. These findings offered a new family of up-conversion materials; more semiconductors with various structural defects are potential complementary members.

2.
Int Wound J ; 20(6): 1903-1910, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36526600

RESUMO

Chronic wounds are very common wound types in clinics which have a prolonged and painful healing process. Chronic wounds affect health-related quality of life (HRQoL) on patients. However, there is no specific instrument to measure the HRQoL in Chinese patients with chronic wounds. Wound-QoL is a questionnaire targeted the experience of health-related life to patients with chronic wounds. The study aims to translate and cross-culturally adapt the Wound-QoL into Chinese and to evaluate its psychometric properties (validity, reliability, floor, and ceiling effect) in a convenience sample of 203 Chinese outpatients with chronic wounds. Reliability was good, with internal consistency of 0.798-0.960 and test-retest reliability of 0.720-0.838. Criterion-related validity was assessed by the correlation coefficient between Wound-QoL and generic European QoL instrument- EQ-5D-5L, which was found statistically significant (P<.001). No signs of floor or ceiling effect could be detected. Further, confirmatory factor analysis (CFA) was used to verify the reliability and validity of the instrument in this study. In conclusion, the Chinese Wound-QoL is a valid and reliable tool for measuring HRQoL in populations with chronic wounds.


Assuntos
Psicometria , Qualidade de Vida , Ferimentos e Lesões , Humanos , População do Leste Asiático/psicologia , Reprodutibilidade dos Testes , Inquéritos e Questionários , Ferimentos e Lesões/psicologia
3.
Animals (Basel) ; 12(12)2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35739854

RESUMO

In the context of global restrictions on the use of antibiotics, there has been increased research on natural plant-based ingredients as additives. It has been proved that many natural active ingredients contained in plants have positive effects on animal growth regulation. Artemisia argyi (A. argyi) is a traditional Chinese herbal medicine, and its extracts have been reported to have a variety of biological activities. Therefore, in order to explore the potential of the active extract of Artemisia argyi leaves (ALE) as a plant source additive, mice were fed with ALE at different concentrations for 60 days. Finally, the effects of ALE were evaluated by the growth indexes, blood indexes, and intestinal microflora changes of the mice. It was found that a medium concentration of ALE (150 mg/kg) could promote growth, and especially improved the feed efficiency of the mice. However, high concentrations of ALE (300 mg/kg) had some negative effects on the growth of mice, especially liver damage, which significantly increased AST and ALT levels in the blood. Therefore, the 150 mg/kg ALE treatment group was selected for 16S rDNA analysis. It was found that ALE could play a positive role by regulating the proportion of Bacteroidetes and Firmicutes in the intestinal tract. In particular, it can significantly up-regulate the quantities of Akkermansia and Bifidobacterium. These results suggest that ALE at appropriate concentrations can positively regulate animal growth.

4.
Materials (Basel) ; 15(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35629551

RESUMO

Traditional solid nanoparticle aerogels have been unable to meet the requirements of practical application due to their inherent brittleness and poor infrared shielding performance. Herein, combining vacuum impregnation and high-temperature pyrolysis, a novel micro/nano-composite fibrous aerogel was prepared via in situ synthesis of silicon carbide nanowires (SiC NWS) in mullite fiber (MF) preform. During this process, uniformly distributed SiC NWS in the MF preform serve as an enhancement phase and also act as an infrared shielding agent to reduce radiation heat transfer, which can significantly improve the mechanical properties of the mullite fiber/silicon carbide nanowire composite aerogels (MF/SiC NWS). The fabricated MF/SiC NWS exhibited excellent thermal stability (1400 °C), high compressive strength (~0.47 MPa), and outstanding infrared shielding performance (infrared transmittance reduced by ~70%). These superior properties make them appealing for their potential in practical application as high-temperature thermal insulators.

5.
Bioengineered ; 13(1): 941-949, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34969353

RESUMO

We aimed to explore the relationships between the plasma expression levels of microRNA (miR)-146a and miR-132 in epileptic patients and cognitive, mental and psychological disorders. Eighty epileptic patients and seventy healthy subjects as controls were evaluated with Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Rating (HAMA) and Hamilton Depression Rating (HAMD) scales, and plasma samples were collected. MiR-146a and miR-132 levels were detected by real-time quantitative PCR. The total incidence rate of cognitive dysfunction, anxiety and depression in epilepsy group was 62.5%. Cognitive dysfunction was correlated positively with educational level, but negatively with disease course, duration and type of administration. The frequency and duration of seizures were positively correlated with anxiety. Depression was correlated negatively with educational level, whereas positively with course of disease and number of used drugs. Epileptic patients had significantly higher miR-146a and miR-132 levels than those of healthy controls. The miR-146a and miR-132 levels of patients with complications were significantly higher than those of cases without complications. Their expressions were correlated negatively with total MoCA scale score, but positively with type of complications. MiR-132 expression was positively correlated with the total scores of HAMA and HAMD scales. Plasma miR-146a and miR-132 expressions increased in epileptic patients, and miR-132 expression reflected the severity of epilepsy and predicted the risks of complications.


Assuntos
Ansiedade/epidemiologia , Depressão/epidemiologia , Epilepsia/psicologia , MicroRNAs/sangue , Regulação para Cima , Adulto , Idoso , Estudos de Casos e Controles , Escolaridade , Epilepsia/sangue , Epilepsia/genética , Feminino , Humanos , Masculino , Testes de Estado Mental e Demência , Pessoa de Meia-Idade , Adulto Jovem
6.
ACS Appl Mater Interfaces ; 13(19): 22765-22773, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-33947180

RESUMO

Nanofibrous aerogels constructed by ceramic fiber components (CNFAs) feature lightweight, compressibility, and high-temperature resistance, which are superior to brittle ceramic aerogels assembled from nanoparticles. Up to now, in order to obtain CNFAs with stable framework and multifunctionality such as hydrophobicity and gas absorption, it is necessary to perform binding and surface modification processes, respectively. However, the microstructure as well as properties of CNFAs are deteriorated by the direct addition of binders and modifiers. To tackle these problems, we introduced a unique low-temperature (100 °C) chemical vapor deposition method (LTCVD) to achieve the cross-linking and hydrophobization of Si3N4 CNFA in only one step. More importantly, during the LTCVD process, SiOx coatings and nanowire arrays were in situ formed via vapor-solid (VS) and vapor-liquid-solid (VLS) mechanisms on the surface and intersection of Si3N4 nanofibers, which cemented the aerogel framework, endowed it with hydrophobicity, and improved its oxidation resistance at high temperature. Compared to most of its counterparts, the Si3N4/SiOx CNFA exhibited better mechanical properties, higher capability of oil/water separation (33-76 g·g-1), lower thermal conductivity (0.0157 W/m·K-1), and superior structural stability in a wide temperature range of -196-1200 °C. This work not only presents an excellent Si3N4/SiOx CNFA for the first time but also provides fresh insights for the exquisite preparation strategy of CNFAs.

7.
Materials (Basel) ; 14(8)2021 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-33921640

RESUMO

In order to improve the mechanical properties of SiO2 aerogels, PHMS/VTES-SiO2 composite aerogels (P/V-SiO2) were prepared. Using vinyltriethoxysilane (VTES) as a coupling agent, the PHMS/VTES complex was prepared by conducting an addition reaction with polyhydromethylsiloxane (PHMS) and VTES and then reacting it with inorganic silica sol to prepare the organic-inorganic composite aerogels. The PHMS/VTES complex forms a coating structure on the aerogel particles, enhancing the network structure of the composite aerogels. The composite aerogels can maintain the high specific surface area and excellent thermal insulation properties, and they have better mechanical properties. We studied the reaction mechanism during preparation and discussed the effects of the organic components on the structure and properties of the composite aerogels. The composite aerogels we prepared have a thermal conductivity of 0.03773 W·m-1·K-1 at room temperature and a compressive strength of 1.87 MPa. The compressive strength is several times greater than that of inorganic SiO2 aerogels. The organic-inorganic composite aerogels have excellent comprehensive properties, which helps to expand the application fields of silicon-based aerogels.

8.
Small ; 16(25): e2001265, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32431059

RESUMO

The design and construction of flexible electrodes that can function at high rates and high areal capacities are essential regarding the practical application of flexible sodium-ion batteries (SIBs) and other energy storage devices, which remains significantly challenging by far. Herein, a flexible and 3D porous graphene nanosheet/SnS2 (3D-GNS/SnS2 ) film is reported as a high-performance SIB electrode. In this hybrid film, the GNS/SnS2 microblocks serve as pillars to assemble into a 3D porous and interconnected framework, enabling fast electron/ion transport; while the GNS bridges the GNS/SnS2 microblocks into a flexible framework to provide satisfactorily mechanical strength and long-range conductivity. Moreover, the SnS2 nanocrystals, which chemically bond with GNS, provide sufficient active sites for Na storage and ensure the cycling stability. Consequently, this flexible 3D-GNS/SnS2 film exhibits excellent Na-storage performances, especially in terms of high areal capacity (2.45 mAh cm-2 ) and high rates with superior stability (385 mAh g-1 at 1.0 A g-1 over 1000 cycles with ≈100% retention). A flexible SIB full cell using this anode exhibits high and stable performance under various bending situations. Thus, this work provide a feasible route to prepare flexible electrodes with high practical viability for not only SIBs but also other energy storage devices.

9.
Mol Brain ; 12(1): 102, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31796120

RESUMO

This study aimed to evaluate the specific regulatory roles of microRNA-146a (miRNA-146a) in temporal lobe epilepsy (TLE) and explore the related regulatory mechanisms. A rat model of TLE was established by intraperitoneal injection of lithium chloride-pilocarpine. These model rats were injected intracerebroventricularly with an miRNA-146a inhibitor and Notch-1 siRNA. Then, neuronal damage and cell apoptosis in the cornu ammonis (CA) 1 and 3 regions of the hippocampus were assessed. SOD and MDA levels in the hippocampus were detected by chromatometry, and IL-1ß, IL-6, and IL-18 levels were detected by ELISA. Then, we evaluated the expression levels of caspase-9, GFAP, Notch-1, and Hes-1 in the hippocampus. The interaction between Notch-1 and miRNA-146a was assessed by a dual luciferase reporter gene assay. A rat model of TLE was successfully established, which exhibited significantly increased miRNA-146a expression in the hippocampus. Silencing of miRNA-146a significantly alleviated the neuronal damage and cell apoptosis in the CA1 and CA3 regions of the hippocampus in TLE rats and decreased MDA, IL-1ß, IL-6, and IL-18 levels and increased SOD levels in the hippocampus of TLE rats. In addition, silencing of miRNA-146a significantly decreased the expression levels of caspase-9, GFAP, Notch-1, and Hes-1 in the hippocampus of TLE rats. Notch-1 was identified as a target of miRNA-146a and silencing of Notch-1 aggravated the neuronal damage in the CA1 and CA3 regions. Silencing of miRNA-146a alleviated the neuronal damage in the hippocampus of TLE rats by down-regulating Notch-1.


Assuntos
Regulação para Baixo/genética , Epilepsia do Lobo Temporal/genética , Inativação Gênica , MicroRNAs/genética , Neurônios/metabolismo , Receptor Notch1/genética , Animais , Apoptose , Sequência de Bases , Caspase 9/metabolismo , Citocinas/metabolismo , Eletroencefalografia , Epilepsia do Lobo Temporal/diagnóstico por imagem , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/metabolismo , Masculino , Malondialdeído/metabolismo , MicroRNAs/metabolismo , Neurônios/patologia , Ratos Wistar , Receptor Notch1/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Transcrição HES-1/metabolismo , Regulação para Cima/genética
10.
J Colloid Interface Sci ; 554: 743-751, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31374518

RESUMO

In this work, the chlorine-doped and undoped hydrothermal carbonation carbon (Cl-HTCC, HTCC) photocatalysts were used to study the correlation of their interfacial charge and photocatalytic performance. For degradation of aromatic dye, rhodamine B (RhB), Cl-HTCC manifests much better photocatalytic performance compared with that of undoped HTCC. Besides the slightly enhanced charge transfer brought, the Cl-HTCC showed more negatively interfacial charge and thus a stronger adsorption of positively charged RhB. This made the photogenerated holes (h+) directly react with the adsorbed RhB, which does not require the h+ to produce hydroxyl radical (OH) and reduce its lost during the transformation, thus enhanced the performance of Cl-HTCC. While for undoped HTCC, it showed a weaker adsorption of RhB, and the photogenerated h+ firstly reacted with H2O molecules to produce OH. Then, the OH can attack the RhB. Besides, the intermediates and the degradation pathways are also evaluated here via UPLC-MS. Results show that the interfacial charge also dominated the degradation pathways. This work provides a novel metal-free photocatalyst for environmental remediation and will inspire further efforts to enhance the photocatalytic performance by concerning interfacial conditions.

11.
Rev Invest Clin ; 71(2): 116-123, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31056609

RESUMO

BACKGROUND: Adenosine A1 receptor (AA1R) is widely present in the central nervous system, exerting brain protective antiepileptic effects, mainly by binding corresponding G proteins. We evaluated the neuroprotective effects of AA1R on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy in rats. MATERIALS AND METHODS: A total of 60 male SD rats were randomly divided into four groups (n = 15/group): normal control, epilepsy, epilepsy + AA1R antagonist (DPCPX), and epilepsy + AA1R agonist (2-CAdo). An epilepsy model was established through kindling by lithium chloride-pilocarpine. The four groups were observed on days 1, 14, and 30. Pathological and morphological changes of hippocampal neurons were observed by HE staining; apoptosis was detected by TUNEL assay. Caspase-3 and GABA receptor expressions were detected by Western blot. RESULTS: In the hippocampal CA3 area of the epilepsy group, the cellular structure was not neatly arranged, and some neurons were swelling, thick, and incomplete. Compared with the epilepsy group at the same time point, cells in the epilepsy + DPCPX group had an increased distortion, disorganization, edema, cytoplasmic vacuoles, and degeneration. In the epilepsy + 2-CAdo group, cell arrangement was regular and orderly, and structural damages were lessened. Compared with the normal control group at the same time point, the epilepsy group underwent evident neuronal apoptosis, with a significantly higher apoptotic index (AI) (p < 0.05). Compared with the epilepsy group, the neuronal apoptosis of the epilepsy + DPCPX group was boosted, and the AI significantly increased (p < 0.05). The neuronal apoptosis of the epilepsy + 2-CAdo group was inhibited, and the AI significantly decreased (p < 0.05). Compared with the epilepsy group, the caspase-3 expression levels of the epilepsy + DPCPX group on days 14 and 30 were significantly upregulated (p < 0.05), but those of the epilepsy + 2-CAdo group were significantly downregulated (p < 0.05). CONCLUSIONS: AA1R abated cell edema and reduced apoptosis, exerting neuroprotective effects on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy.


Assuntos
Agonistas do Receptor A1 de Adenosina/farmacologia , Epilepsia/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Animais , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Hipocampo/patologia , Cloreto de Lítio/toxicidade , Masculino , Neurônios/patologia , Pilocarpina/toxicidade , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
12.
Rev. invest. clín ; 71(2): 116-123, Mar.-Apr. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1289677

RESUMO

Abstract Background Adenosine A1 receptor (AA1R) is widely present in the central nervous system, exerting brain protective antiepileptic effects, mainly by binding corresponding G proteins. We evaluated the neuroprotective effects of AA1R on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy in rats. Materials and Methods A total of 60 male SD rats were randomly divided into four groups (n = 15/group): normal control, epilepsy, epilepsy + AA1R antagonist (DPCPX), and epilepsy + AA1R agonist (2-CAdo). An epilepsy model was established through kindling by lithium chloride-pilocarpine. The four groups were observed on days 1, 14, and 30. Pathological and morphological changes of hippocampal neurons were observed by HE staining; apoptosis was detected by TUNEL assay. Caspase-3 and GABA receptor expressions were detected by Western blot. Results In the hippocampal CA3 area of the epilepsy group, the cellular structure was not neatly arranged, and some neurons were swelling, thick, and incomplete. Compared with the epilepsy group at the same time point, cells in the epilepsy + DPCPX group had an increased distortion, disorganization, edema, cytoplasmic vacuoles, and degeneration. In the epilepsy + 2-CAdo group, cell arrangement was regular and orderly, and structural damages were lessened. Compared with the normal control group at the same time point, the epilepsy group underwent evident neuronal apoptosis, with a significantly higher apoptotic index (AI) (p < 0.05). Compared with the epilepsy group, the neuronal apoptosis of the epilepsy + DPCPX group was boosted, and the AI significantly increased (p < 0.05). The neuronal apoptosis of the epilepsy + 2-CAdo group was inhibited, and the AI significantly decreased (p < 0.05). Compared with the epilepsy group, the caspase-3 expression levels of the epilepsy + DPCPX group on days 14 and 30 were significantly upregulated (p < 0.05), but those of the epilepsy + 2-CAdo group were significantly downregulated (p < 0.05). Conclusions AA1R abated cell edema and reduced apoptosis, exerting neuroprotective effects on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy.


Assuntos
Animais , Masculino , Ratos , Fármacos Neuroprotetores/farmacologia , Epilepsia/tratamento farmacológico , Agonistas do Receptor A1 de Adenosina/farmacologia , Hipocampo/efeitos dos fármacos , Pilocarpina/toxicidade , Fatores de Tempo , Ratos Sprague-Dawley , Apoptose/efeitos dos fármacos , Cloreto de Lítio/toxicidade , Modelos Animais de Doenças , Hipocampo/patologia , Neurônios/patologia
13.
J Hazard Mater ; 371: 352-361, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-30856446

RESUMO

Porous metal oxides are promising materials for VOCs (volatile organic compounds) chemical sensors, because they have large specific surface areas and enough internal space for the fast gas diffusion. Recently, metal-organic framework (MOF) materials with varied shapes and sizes have been regarded as good templates for preparing porous metal oxides. Herein, four kinds of Co-MOFs were prepared by altering the ratios of Co2+ ions and 2-methylimidazole at room temperature, which exhibited well-controlled shapes. Then, corresponding porous Co3O4 assembled from nanoparticles was acquired by heating Co-MOFs, and showed a good sensing performance for n-butanol, with a response up to 21.0 toward 100 ppm n-butanol. Moreover, it is found that the shape and the size of Co3O4 assemblies can significantly influence their sensing performances. For porous Co3O4 assemblies, when the nanoparticles are small enough (˜10 nm), a porous structure with a larger proportion of the nanoparticles close to its surface tends to show a better gas-sensing performance. The findings can be used in the design of gas-sensing materials in the future.

14.
Angew Chem Int Ed Engl ; 57(30): 9351-9356, 2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-29870143

RESUMO

Oxygen activation plays a crucial role in many important chemical reactions such as oxidation of organic compounds and oxygen reduction. For developing highly active materials for oxygen activation, herein, we report an atomically dispersed Pt on WO3 nanoplates stabilized by in situ formed amorphous H2 WO4 out-layer and the mechanism for activating molecular oxygen. Experimental and theoretical studies demonstrate that the isolated Pt atoms coordinated with oxygen atoms from [WO6 ] and water of H2 WO4 , consequently leading to optimized surface electronic configuration and strong metal-support interaction (SMSI). In exemplified reactions of butanone oxidation sensing and oxygen reduction, the atomic Pt/WO3 hybrid exhibits superior activity than those of Pt nanoclusters/WO3 and bare WO3 as well as enhanced long-term durability. This work will provide insight into the origin of activity and stability for atomically dispersed materials, thus promoting the development of highly efficient and durable single atom-based catalysts.

15.
J Hazard Mater ; 346: 199-207, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29275109

RESUMO

Bacterial cellulose aerogels/silica aerogels (BCAs/SAs) are prepared using three-dimensional self-assembled BC skeleton as reinforcement and methyltriethoxysilane derived silica aerogels as filler through vacuum infiltration and freeze drying. The BCAs/SAs possess a hierarchical cellular structure giving them superelasticity and recyclable compressibility. The BCAs/SAs can bear a compressive strain up to 80% and recover their original shapes after the release of the stress. The BCAs/SAs exhibit super-hydrophobicity with a contact angle of 152° and super-oleophilicity resulting from the methyl groups on the surface of silica aerogel filler. This endows the BCAs/SAs outstanding oil absorbing capability with the quality factor Q from 8 to 14 for organic solvents and oils. Moreover, the absorbed oil can be retrieved by mechanically squeezed with a recovery of 88% related to the superelastic ability of the composites. In addition, the oil absorbing of BS/SAs could be well maintained with the quality factor Q about 11 for gasoline after harsh conditional treatment down to -200 °C and up to 300 °C. Such outstanding elastic and oleophilic properties make the BC/SAs tremendous potential for applications of oil absorbing, recovery and oil-water separation.


Assuntos
Celulose/química , Géis/química , Óleos/química , Dióxido de Silício/química , Poluentes Químicos da Água/química , Adsorção , Bactérias , Elasticidade , Recuperação e Remediação Ambiental , Interações Hidrofóbicas e Hidrofílicas , Petróleo , Reciclagem
16.
Angew Chem Int Ed Engl ; 56(29): 8407-8411, 2017 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-28052568

RESUMO

0D/2D heterojunctions, especially quantum dots (QDs)/nanosheets (NSs) have attracted significant attention for use of photoexcited electrons/holes due to their high charge mobility. Herein, unprecedent heterojunctions of vanadate (AgVO3 , BiVO4 , InVO4 and CuV2 O6 ) QDs/graphitic carbon nitride (g-C3 N4 ) NSs exhibiting multiple unique advances beyond traditional 0D/2D composites have been developed. The photoactive contribution, up-conversion absorption, and nitrogen coordinating sites of g-C3 N4 NSs, highly dispersed vanadate nanocrystals, as well as the strong coupling and band alignment between them lead to superior visible-light-driven photoelectrochemical (PEC) and photocatalytic performance, competing with the best reported photocatalysts. This work is expected to provide a new concept to construct multifunctional 0D/2D nanocomposites for a large variety of opto-electronic applications, not limited in photocatalysis.

17.
J Hazard Mater ; 276: 262-70, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24892776

RESUMO

Hierarchical nanostructured ZnO dandelion-like spheres were synthesized via solvothermal reaction at 200°C for 4h. The products were pure hexagonal ZnO with large exposure of (002) polar facet. Side-heating gas sensor based on hierarchical ZnO spheres was prepared to evaluate the acetone gas sensing properties. The detection limit to acetone for the ZnO sensor is 0.25ppm. The response (Ra/Rg) toward 100ppm acetone was 33 operated at 230°C and the response time was as short as 3s. The sensor exhibited remarkable acetone selectivity with negligible response toward other hazardous gases and water vapor. The high proportion of electron depletion region and oxygen vacancies contributed to high gas response sensitivity. The hollow and porous structure of dandelion-like ZnO spheres facilitated the diffusion of gas molecules, leading to a rapid response speed. The largely exposed (002) polar facets could adsorb acetone gas molecules easily and efficiently, resulting in a rapid response speed and good selectivity of hierarchical ZnO spheres gas sensor at low operating temperature.


Assuntos
Acetona/análise , Substâncias Perigosas , Odorantes , Óxido de Zinco/química , Microscopia Eletrônica
18.
J Nanosci Nanotechnol ; 14(6): 4278-85, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24738383

RESUMO

Carbon-coated MoO2 nanocrystallines with uniform particle size and carbon-coating morphology have been fabricated by a green and economical hydrothermal route and carbonization process. Glucose here acts as a multifunctional agent, not only as the reducing species to prepare MoO2, but also as the carbonaceous precursor and coating agent to form the carbon-coated and nanoscale MoO2 crystallines. The electrochemical tests demonstrate that the as-synthesized carbon-coated MoO2 nanocrystallines exhibit high capacity and excellent capacity retention as an anode material for lithium-ion batteries. The specific discharge capacity is as high as 790 mA h g(-1) in the first cycle and 730 mA h g(-1) over 50 cycles. The significant enhancement in the electrochemical Li storage performance is attributed to the synergistic effect of the nanocrystallines structure with small particle size and uniform carbon-coating shell, which reduces the diffusion distance for Li-ion and electron, provides high electric conductivity and relieves the volume effect during the cycling.


Assuntos
Carbono/química , Fontes de Energia Elétrica , Química Verde/métodos , Lítio/química , Lítio/isolamento & purificação , Molibdênio/química , Nanoestruturas/química , Óxidos/química , Adsorção , Cristalização/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Nanoestruturas/ultraestrutura , Tamanho da Partícula
19.
ACS Appl Mater Interfaces ; 6(1): 401-9, 2014 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-24308308

RESUMO

Ordered mesoporous In2O3 gas-sensing materials with controlled mesostructured morphology and high thermal stability have been successfully synthesized via a nanocasting method in conjunction with the container effect. The mesostructured ordering, as well as the particle size, crystallinity and pore size distribution have been proved to vary in a large range by using the XRD, SAXRD, SEM, TEM, and nitrogen physisorption techniques. The control of the mesostructured morphology was carried out by tuning the transportation rate of indium precursor in template channel resulting from the different escape rate of the decomposed byproducts via the varied container opening and shapes. The particular relation between the mesostructured ordering and gas sensing property of mesoporous In2O3 was examined in detail. It was found that the ordered mesoporous In2O3 with appropriate mesostructured morphology exhibited significantly improved ethanol sensitivity, response and selectivity performances in comparison with the other ordered mesoporous In2O3, which benefits from the large surface area with enough sensing active sites, proper pore distribution for sufficient gas diffusion, and appropriate particle size for effective electron depletion. The resulting sensing behaviors lead to a better understanding of designing and using such mesoporous metal oxides for a number of gas-sensing applications.

20.
Nanoscale Res Lett ; 5(3): 644-648, 2010 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-20672076

RESUMO

Large-scale uniform ZnO dumbbells and ZnO/ZnS hollow nanocages were successfully synthesized via a facile hydrothermal route combined with subsequent etching treatment. The nanocages were formed through preferential dissolution of the twinned (0001) plane of ZnO dumbbells. Due to their special morphology, the hollow nanocages show better sensing properties to ethanol than ZnO dumbbells. The gain in sensitivity is attributed to both the interface between ZnO and ZnS heterostructure and their hollow architecture that promotes analyte diffusion and increases the available active surface area.

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