Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 161
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Chem Soc Rev ; 53(2): 714-763, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38105711

RESUMO

As an important strategic resource, rare earths (REs) constitute 17 elements in the periodic table, namely 15 lanthanides (Ln) (La-Lu, atomic numbers from 57 to 71), scandium (Sc, atomic number 21) and yttrium (Y, atomic number 39). In the field of catalysis, the localization and incomplete filling of 4f electrons endow REs with unique physical and chemical properties, including rich electronic energy level structures, variable coordination numbers, etc., making them have great potential in electrocatalysis. Among various RE catalytic materials, rare earth oxide (REO)-based electrocatalysts exhibit excellent performances in electrocatalytic reactions due to their simple preparation process and strong structural variability. At the same time, the electronic orbital structure of REs exhibits excellent electron transfer ability, which can reduce the band gap and energy barrier values of rate-determining steps, further accelerating the electron transfer in the electrocatalytic reaction process; however, there is a lack of systematic review of recent advances in REO-based electrocatalysis. This review systematically summarizes the synthesis, properties and applications of REO-based nanocatalysts and discusses their applications in electrocatalysis in detail. It includes the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), methanol oxidation reaction (MOR), nitrogen reduction reaction (NRR) and other electrocatalytic reactions and further discusses the catalytic mechanism of REs in the above reactions. This review provides a timely and comprehensive summary of the current progress in the application of RE-based nanomaterials in electrocatalytic reactions and provides reasonable prospects for future electrocatalytic applications of REO-based materials.

2.
Chem Soc Rev ; 53(4): 2211-2247, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38240305

RESUMO

Recently, high-entropy (HE) materials have attracted increasing interest in various fields due to their unique characteristics. Rare earth (RE) elements have a similar atomic radius and gradually occupied 4f orbitals, endowing them with abundant optical, electric, and magnetic properties. Furthermore, HE-RE materials exhibit good structural and thermal stability and various functional properties, emerging as an important class of HE materials, which are on the verge of rapid development. However, a comprehensive review focusing on the introduction and in-depth understanding of HE-RE materials has not been reported to date. Thus, this review endeavors to provide a comprehensive summary of the development and research status of HE-RE materials, including alloys and ceramics, ranging from their structure, synthesis, and properties to applications. In addition, some distinctive issues of HR-RE materials related to the special electronic structure of RE are also discussed. Finally, we put forward the current challenges and future development directions of HE-RE materials. We hope that this review will provide inspiration for new design ideas and valuable references in this emerging field in the future.

3.
J Am Chem Soc ; 146(13): 9012-9025, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38516778

RESUMO

The development of efficient and stable catalysts for hydrogen production from electrolytic water in a wide pH range is of great significance in alleviating the energy crisis. Herein, Pt nanoparticles (NPs) anchored on the vacancy of high entropy rare earth oxides (HEREOs) were prepared for the first time for highly efficient hydrogen production by water electrolysis. The prepared Pt-(LaCeSmYErGdYb)O showed excellent electrochemical performances, which require only 12, 57, and 77 mV to achieve a current density of 100 mA cm-2 in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M PBS environments, respectively. In addition, Pt-(LaCeSmYErGdYb)O has successfully worked at 400 mA cm-2 @ 60 °C for 100 h in 0.5 M H2SO4, presenting the high mass activity of 37.7 A mg-1Pt and turnover frequency (TOF) value of 38.2 s-1 @ 12 mV, which is far superior to the recently reported hydrogen evolution reaction (HER) catalysts. Density functional theory (DFT) calculations have revealed that the interactions between Pt and HEREO have optimized the electronic structures for electron transfer and the binding strength of intermediates. This further leads to optimized proton binding and water dissociation, supporting the highly efficient and robust HER performances in different environments. This work provides a new idea for the design of efficient RE-based electrocatalysts.

4.
Small ; 20(12): e2307052, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37946708

RESUMO

Design of highly efficient electrocatalysts for alkaline hydrogen evolution reaction (HER) is of paramount importance for water electrolysis, but still a considerable challenge because of the slow HER kinetics in alkaline environments. Alloying is recognized as an effective strategy to enhance the catalytic properties. Lanthanides (Ln) are recognized as an electronic and structural regulator, attributed to their unique 4f electron behavior and the phenomenon known as lanthanide contraction. Here, a new class of Rh3Ln intermetallics (IMs) are synthesized using the sodium vapor reduction method. The alloying process induced an upshift of the d-band center and electron transfer from Ln to Rh, resulting in optimized adsorption and dissociation energies for H2O molecules. Consequently, Rh3Tb IMs exhibited outstanding HER activity in both alkaline environments and seawater, displaying an overpotential of only 19 mV at 10 mA cm-2 and a Tafel slope of 22.2 mV dec-1. Remarkably, the current density of Rh3Tb IMs at 100 mV overpotential is 8.6 and 5.7 times higher than that of Rh/C and commercial Pt/C, respectively. This work introduces a novel approach to the rational design of HER electrocatalysis and sheds light on the role of lanthanides in electrocatalyst systems.

5.
Small ; : e2400662, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38534137

RESUMO

Developing high-performance electrocatalysts for alkaline hydrogen evolution reaction (HER) is crucial for producing green hydrogen, yet it remains challenging due to the sluggish kinetics in alkaline environments. Pt is located near the peak of HER volcano plot, owing to its exceptional performance in hydrogen adsorption and desorption, and Rh plays an important role in H2O dissociation. Lanthanides (Ln) are commonly used to modulate the electronic structure of materials and further influence the adsorption/desorption of reactants, intermediates, and products, and noble metal-Ln alloys are recognized as effective platforms where Ln elements regulate the catalytic properties of noble metals. Here Pt1.5Rh1.5Tm alloy is synthesized using the sodium vapor reduction method. This alloy demonstrates superior catalytic activity, being 4.4 and 6.6 times more effective than Pt/C and Rh/C, respectively. Density Functional Theory (DFT) calculations reveal that the upshift of d-band center and the charge transfer induced by alloying promote adsorption and dissociation of H2O, making Pt1.5Rh1.5Tm alloy more favorable for the alkaline HER reaction, both kinetically and thermodynamically.

6.
Small ; 20(26): e2310238, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38267815

RESUMO

Cesium lead halide (CsPbX3, X = Br, Cl, and I) nanocrystals (NCs) are widely concerned and applied in many fields due to the excellent photoelectric performance. However, the toxicity of Pb and the loss of luminescence in water limit its application in vivo. A stable perovskite nanomaterial with good bioimaging properties is developed by incorporating europium (Eu) in CsPbX3 NCs followed with the surface coating of silica (SiO2) shell (CsPbX3:Eu@SiO2). Through the surface coating of SiO2, the luminescence stability of CsPbBr3 in water is improved and the leakage of Pb2+ is significantly reduced. In particular, Eu doping inhibits the photoluminescence quantum yield reduction of CsPbBr3 caused by SiO2 coating, and further reduces the release of Pb2+. CsPbBr3:Eu@SiO2 nanoparticles (NPs) show efficient luminescence in water and good biocompatibility to achieve cell imaging. More importantly, CsPb(ClBr)3:Eu@SiO2 NPs are obtained by adjusting the halogen components, and green light and blue light are realized in zebrafish imaging, showing good imaging effect and biosafety. The work provides a strategy for advanced perovskite nanomaterials toward biological practical application.


Assuntos
Césio , Európio , Chumbo , Luminescência , Nanopartículas , Dióxido de Silício , Água , Peixe-Zebra , Animais , Dióxido de Silício/química , Európio/química , Nanopartículas/química , Chumbo/química , Césio/química , Água/química , Titânio/química , Óxidos , Compostos de Cálcio
7.
Zhongguo Zhong Yao Za Zhi ; 49(6): 1485-1493, 2024 Mar.
Artigo em Zh | MEDLINE | ID: mdl-38621932

RESUMO

Chuanxiong Rhizoma is a well-known Sichuan-specific herbal medicine. Its original plant, Ligusticum chuanxiong, has been cultivated asexually for a long time. L. chuanxiong has sexual reproductive disorders, which restricts its germplasm innovation. However, there is little research on the reproductive system of L. chuanxiong. This study is based on a comparative anatomical research approach, using morphological dissection, paraffin sectioning, staining and compression, and combined with scanning electron microscopy technology, to observe and compare the flowers, fruits, and seeds at various stages of reproductive growth of L. chuanxiong and its wild relative L. sinense. The results showed that the meiosis of pollen mother cells is abnormal in L. chuanxiong anthers, and the size and number of microspores are uneven and inconsistent in the tetrad stage. tapetum cells are not completely degenerated during anther development. During the pollen ripening stage, there are fine cracks in the anther wall, while most anthers could not release pollen normally. The surface of mature pollen grains is concave and partially deformed, and the pollens are all inactive and cannot germinate in vitro. The starch, polysaccharides, and lipids in the pollen were insufficient. The filaments of L. chuanxiong are short at the flowering stage and recurved downward. Double-hanging fruits were observed in the fruiting stage, being wrinkled; with shriveled seeds. Compared with L. sinense at the same stage, the anthers of L. sinense developed normally, and the pollen grains are vigorous and can germinate in vitro. The double-hanging fruits of L. sinense are full and normal; at the flowering period, the filaments are long and erect, significantly higher than the stigma. Mature blastocysts are visible in the ovary of both L. chuanxiong and L. sinense, and there is no significant difference in stigmas. The conclusion is that during the development of L. chuanxiong stamens, the meiosis of pollen mother cells is abnormal, and tetrad, tapetum, filament and other pollen structures develop abnormally. L. chuanxiong has the characteristic of male infertility, which is an important reason for its sexual reproductive disorders.


Assuntos
Ligusticum , Reprodução , Pólen , Flores , Polissacarídeos
8.
Small ; 19(33): e2301392, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37086136

RESUMO

As an important lanthanide (Ln)-based functional materials, the Ln chalcogenides possess unique properties and various applications. However, the controllable synthesis of Ln chalcogenide nanocrystals still faces great challenges because of the rather poor affinity between Ln and chalcogenide ions (S, Se, Te) as well as strong preference of combination with existed oxygen. Herein, a facile but general heterogeneous nucleation synthetic strategy is established toward a series of colloidal ternary Cu Ln sulfides nanocrystals using the Ln dithiocarbamates and CuI as precursors. To extend this synthetic protocol, similar strategy is used to prepare six kinds of high quality CuLnS2 nanocrystals, while the bulk ones are only obtained by the traditional solid-state reaction at rigorous condition. Importantly, high-entropy nanocrystals CuLnS2 and CuEux Ln2-x S3 which contain six Ln elements (Nd, Sm, Gd, Tb, Dy) are readily obtained by the co-decomposed process attributed to their similar diffusion speed. As a proof-of-concept application, CuEu2 S3 nanocrystals showed efficient photocatalytic hydrogen production properties.

9.
Small ; 18(21): e2201332, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35451152

RESUMO

To address the environmental crisis caused by excessive emissions of CO2 , the development of effective photocatalysts for the conversion of CO2 into chemicals has emerged as one of the most promising strategies. Herein, beyond those well-studied materials, a rare-earth sulfide-based nanocrystal NaCeS2 is fabricated and investigated for efficient and selective conversion of CO2 into CO, where the role of Ce ions is crucial. Firstly, the hybridization of Ce 4f and Ce 5d orbitals contributes to the photoresponsive band structure of NaCeS2 . Secondly, due to the charge rearrangement supplied by the incompletely filled 4f orbitals of Ce ions, NaCeS2 exhibits excellent charge separation efficiency and CO2 adsorption affinity, reducing the energy barrier for the conversion from CO2 to CO. Moreover, a NaCeS2 -MoS2 heterostructure is also designed to further boost the electron transfer from the Mo site to the Ce site, which results in an improvement of the catalytic reduction yield from 7.24 to 23.42 µmol g-1 within 9 h (both better than TiO2 controls). This work offers a platform for the development of rare-earth-based photocatalysts for CO2 conversion.

10.
Small ; 18(33): e2201642, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35843870

RESUMO

The development of advanced electronic devices is boosting many aspects of modern technology and industry. The ever-increasing demand for advanced electrical devices and integrated circuits calls for the design of novel materials, with superior properties for the improvement of working performance. In this review, a detailed overview of the synthesis strategies of 2D metal organic frameworks (MOFs) acquiring growing attention is presented, as a basis for expansion of novel key materials in electrical devices and integrated circuits. A framework of controllable synthesis routes to be implanted in the synthesis strategies of 2D materials and MOFs is described. In short, the synthesis methods of 2D MOFs are summarized and discussed in depth followed by the illustrations of promising applications relating to various electrical devices and integrated circuits. It is concluded by outlining how 2D MOFs can be synthesized in a simpler, highly efficient, low-cost, and more environmentally friendly way which can open up their applicable opportunities as key materials in advanced electrical devices and integrated circuits, enabling their use in broad aspects of the society.


Assuntos
Estruturas Metalorgânicas , Eletricidade
11.
Artigo em Inglês | MEDLINE | ID: mdl-35244532

RESUMO

The 16S rRNA gene sequences of Pseudobizionia ponticola MM-14T and Hanstruepera crassostreae L53T shared 100 % sequence similarity. This study aimed to clarify the taxonomic position of the two species. Whole-genome comparisons showed that P. ponticola MM-14T and H. crassostreae L53T shared average nucleotide identity of 97.52 %, digital DNA-DNA hybridization of 75.30 % and average amino acid identity of 96.98 %. These values exceeded the threshold of bacterial species delineation. Furthermore, average amino acid identities of P. ponticola MM-14T and H. crassostreae L53T in comparison with Hanstruepera neustonica CC-PY-50T were 82.04 and 82.11 %, respectively. Phylogenetic analysis based on 16S rRNA gene and 120 bacterial conserved single-copy genes also supported that P. ponticola MM-14T and H. crassostreae L53T belonged to the genus Hanstruepera. Phenotypic and chemical taxonomic properties compared between P. ponticola MM-14T and H. crassostreae L53T were nearly identical. Colonies of the two species on marine agar plates were orange-pigmented, circular and smooth. Flexirubin-type pigments were present in both H. crassostreae L53T and P. ponticola MM-14T. The major fatty acids composition of the two species consisted of iso-C15 : 1 G, iso-C15 : 0, and iso-C17 : 0 3-OH, similar to H. neustonica CC-PY-50T. Based on priority, H. crassostreae He et al. 2018 is a later heterotypic synonym of P. ponticola Park et al. 2018, and P. ponticola should be transferred to the genus Hanstruepera as Hanstruepera ponticola comb. nov.


Assuntos
Ácidos Graxos , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
12.
Skin Res Technol ; 28(5): 719-728, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35785442

RESUMO

BACKGROUND: Facial skin characteristics and appearance vary according to ethnicity. While much of this knowledge is derived from the Caucasian population, lately there have been efforts to gain such understanding in various regions in Asia.  In this paper, we have built an understanding of such features in Indonesia. In Indonesia, a section of females wears a traditional veil (hijab) to cover the scalp and part of face. The influence of the hijab on facial skin attributes was also investigated. METHODS: In a cross-sectional observational study design involving 419 female volunteers in Jakarta, Indonesia, facial skin attributes (colour, radiance, hydration, trans-epidermal water loss [TEWL], wrinkles, fine lines, pores, and sebum levels) and conditions (melasma, post-inflammatory hyperpigmentation (PIH), solar lentigines/ senile lentigines, seborrheic keratoses and acne) were assessed by trained operators and dermatologists using standard validated instruments and scales. RESULTS: With age, facial skin colour showed darkening in cheek; forehead on the other hand showed slight lightening. The skin evenness and radiance decreased, substantially. Aging attributes measured in terms of lines, wrinkles, and under-eye dark circles showed deterioration with age; the decline was progressively faster than colour change. Facial image data analysis corroborated these findings. Skin hydration remained similar across the age groups even though the skin barrier function measured in terms of TEWL improved with age. Sebum levels in the skin were similar up to the age of 50 but declined in the next group of 50-60 year. Pore severity increased with age. Melasma, seborrheic keratosis and PIH showed a high prevalence (>∼50%) at the young age group (20-30 years), itself. Melasma prevalence attained 100% in the age group of 41-50 year and onwards, and its severity similarly showed a steady rise with age. PIH on the other hand showed a steady decline with age. Solar lentigines prevalence (∼30%) did not change much across age groups, and the severity scores were similar in age groups up to 50 year but increased substantially in 51-60-year age groups. Seborrheic keratosis was similar (∼47%) in age groups up 20-40 year but steadily increased in upper age groups. Its severity was similar in the age groups of 20-30 year and 31-40 year but showed a two-fold increase in subsequent age groups. Acne was 10% in the age group of 20-30 year and declined gradually to 0.7% in the 51-60-year age group. Hijab wearers showed slight protection in skin colour darkening and improvement of evenness and radiance but were similar on aging (fine lines and wrinkles on crow's feet, under eye and peri-oral areas) markers to non-wearers. In general, in majority of age-groups, hijab wearers showed a higher prevalence of melasma, solar/senile lentigines, seborrheic keratosis and PIH.


Assuntos
Acne Vulgar , Hiperpigmentação , Ceratose Seborreica , Lentigo , Melanose , Envelhecimento da Pele , Adulto , Estudos Transversais , Feminino , Humanos , Hiperpigmentação/epidemiologia , Indonésia/epidemiologia , Pessoa de Meia-Idade , Água , Adulto Jovem
13.
Nano Lett ; 21(21): 9325-9331, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34677073

RESUMO

Rare-earth (RE) solid-state halide electrolytes have been extensively studied recently in the field of lithium (Li) ion all-solid-state batteries (ASSBs) due to their excellent electrochemical performances. Herein, a new RE-based solid halide electrolyte Li3HoBr6 (LHB) has been synthesized and exhibits high Li ion conductivity up to mS cm-1 at room temperature. Theoretical calculations have identified four different Li ion migration pathways, in which the out-of-plane pathways are much more favorable than the direct in-plane pathways. In addition, LHB has a wider electrochemical window in comparison to a sulfide solid electrolyte and good deformability. The LHB-based Li-sulfur ASSB assembled by cold pressing can exhibit good cycling stability with high Coulombic efficiency, which shows that LHB has potential application in ASSBs.

14.
Int J Cosmet Sci ; 44(1): 103-117, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34958693

RESUMO

OBJECTIVES: To demonstrate the synergistic effect of 4-hexylresorcinol (4-HR) with niacinamide in boosting anti-melanogenic efficacy in vitro and establish the in vivo efficacy and safety of the combination in a human trial. METHODS: Primary human epidermal melanocytes and 3D pigmented skin equivalents were treated with 4-HR, niacinamide, and their combinations for their effect on pigmentation. This was followed by a randomized, double-blind, split-face clinical study in Chinese subjects, and effects on skin tone, hyperpigmentation, fine lines and wrinkles, hydration, and skin firmness were measured for a 12-week study period. RESULTS: In vitro tyrosinase enzyme activity studies showed that 4-HR is one of the most potent tyrosinase inhibitors. The combination of 4-HR and niacinamide showed a synergistic reduction in melanin production in cultured melanocytes and lightened the 3D skin equivalent model. In vitro as well as in the human trial, the combination of 4-HR and niacinamide showed significantly improved efficacy over niacinamide alone on hyperpigmentation spots as measured by L*, the visual appearance of fine lines and wrinkles in crow's feet and perioral area and skin firmness, with no product-related adverse events. CONCLUSIONS: A formulation containing a combination of 4-HR and niacinamide delivered superior skin tone and anti-ageing benefits significantly better than niacinamide alone with no adverse events. This study demonstrates that a product designed to affect multiple pathways of melanogenesis, inflammation, and ageing may provide an additional treatment option, beyond hydroquinone and retinoids, for hyperpigmentation and ageing.


OBJECTIFS: Démontrer l'effet synergique du 4-hexylrésorcinol (4-HR) associé au niacinamide pour stimuler in vitro l'efficacité antimélanogène, et établir l'efficacité et la sécurité d'emploi in vivo de cette association dans un essai chez l'homme. MÉTHODES: Des mélanocytes épidermiques humains primaires et des équivalents cutanés pigmentés en 3D ont été traités avec du 4-HR, du niacinamide et leurs combinaisons pour leur effet sur la pigmentation. Ceci a été suivi d'une étude clinique randomisée, en double aveugle en hémi-visage chez des sujets chinois, et les effets sur le teint, l'hyperpigmentation, les rides et ridules, l'hydratation et la fermeté de la peau ont été mesurés pendant une durée d'étude de 12 semaines. RÉSULTATS: Les études in vitro sur l'activité enzymatique de la tyrosinase ont montré que le 4-HR est l'un des inhibiteurs de la tyrosinase les plus puissants. L'association du 4-HR et du niacinamide a montré une réduction synergique de la production de mélanine dans les mélanocytes de culture et donné de la luminosité au modèle cutané 3D équivalent. Également in vitro avec l'étude chez l'homme, l'association du 4-HR et du niacinamide a fait ressortir une efficacité significativement plus élevée qu'avec le niacinamide seul sur les taches d'hyperpigmentation mesurées par L*, l'aspect visuel des rides et ridules des pattes d'oie et de la zone périorale, et la fermeté de la peau, sans événements indésirables liés au produit. CONCLUSIONS: Une formulation contenant une association de 4-HR et de niacinamide a permis d'obtenir un teint et un effet anti-âge nettement supérieurs à ceux du niacinamide seul, sans événements indésirables. Cette étude démontre qu'un produit conçu pour toucher plusieurs voies de mélanogenèse, d'inflammation et de vieillissement peut constituer une nouvelle option thérapeutique, au-delà de l'hydroquinone et des rétinoïdes, pour l'hyperpigmentation et le vieillissement.


Assuntos
Hexilresorcinol , Hiperpigmentação , Envelhecimento , Hexilresorcinol/uso terapêutico , Humanos , Hiperpigmentação/tratamento farmacológico , Niacinamida/farmacologia , Pigmentação da Pele
15.
Angew Chem Int Ed Engl ; 61(45): e202212251, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36109346

RESUMO

Ultrathin nanowires (NWs) have always attracted the attention of researchers due to their unique properties, but their facile synthesis is still a great challenge. Herein we developed a general method for the synthesis of rare earth (RE) oxide ultrathin NWs at atmospheric pressure and low temperature (50 °C). The formation mechanism of ultrathin NWs lies in two aspects: thermodynamic advantage of one dimensional (1D) growth at low temperature, and supplement of effective monomers. As an extension, fifteen kinds of RE oxide ultrathin NWs were synthesized through this strategy, and they all exhibited polymer-like behaviors. Meanwhile, the high viscosity, organic gel, wet- and electro-spinning of Ce-Mo-O NWs were studied in detail, demonstrating the similarity of ultrathin inorganic NWs to polymers. In addition, the Ce-Mo-O ultrathin NWs were used as photocatalysts for toluene oxidation and showed excellent performance with toluene conversion ratio of 83.8 %, suggesting their potential application in organic photocatalysis.

16.
Small ; 17(22): e2005371, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33605028

RESUMO

The development of catalytic conversion is very important for human society. In the catalytic process, metal-organic frameworks (MOFs) can be utilized to obtain effective catalysts for their porous structures and adjustable properties. In addition, the introduction of rare-earth (RE) elements with unique properties for catalysts can realize good catalytic performances. Thus, the RE-MOF related catalysts for catalytic conversion are summarized. Due to the cooperation of RE elements and porous MOF structures, the RE-based MOFs can be used as promising catalysts or precursors/supports for other catalysts in the areas of energy conversion, environmental governance, and organic synthesis. These aggregated studies highlight the RE-MOFs as promising candidates for catalytic conversion.


Assuntos
Estruturas Metalorgânicas , Metais Terras Raras , Catálise , Conservação dos Recursos Naturais , Política Ambiental , Humanos
17.
Small ; 17(49): e2104423, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34708548

RESUMO

Layered double hydroxides (LDHs) have been considered as promising electrodes for supercapacitors due to their adjustable composition, designable function and superior high theoretic capacity. However, their experimental specific capacity is significantly lower than the theoretical value due to their small interlayer spacing. Therefore, obtaining large interlayer spacing through the intercalation of large-sized anions is an important means to improve capacity performance. Herein, a metal organic framework derived cobalt-nickel layered double hydroxide hollowcage intercalated with different concentrations of 1,4-benzenedicarboxylic acid (H2 BDC) through in-situ cationic etching and organic ligand intercalation method is designed and fabricated. The superior specific capacity and excellent rate performance are benefit from the large specific surface area of the hollow structure and increasing interlayer spacing of LDH after H2 BDC intercalation. The sample with the largest layer spacing displays a maximum specific capacity of 229 mA h g-1 at 1 A g-1 . In addition, the hybrid supercapacitor assembled from the sample with the largest layer spacing and active carbon electrode has a maximum specific capacity of 158 mA h g-1 at 1 A g-1 ; the energy density is as high as 126.4 W h kg-1 at 800 W kg-1 and good cycle stability.

18.
Small ; 17(11): e2006617, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33605080

RESUMO

A robust polyaniline-assisted strategy is developed to construct a self-supported electrode constituting a nitrogen, phosphorus, sulfur tri-doped thin graphitic carbon layer encapsulated sulfur-doped molybdenum phosphide nanosheet array (NPSCL@S-MoP NSs/CC) with accessible nanopores, desirable chemical compositions, and stable composite structure for efficient hydrogen evolution reaction (HER). The multiple electronic coupling effects of S-MoP with N, P, S tri-dopants afford effective regulation on their electrocatalytic performance by endowing abundant accessible active sites, outstanding charge-transfer property, and d-band center downshift with a thermodynamically favorable hydrogen adsorption free energy (ΔGH* ) for efficient hydrogen evolution catalysis. As a result, the NPSCL@S-MoP NSs/CC electrode exhibits overpotentials as low as 65, 114, and 49 mV at a geometric current density of 10 mA cm-2 and small Tafel slopes of 49.5, 69.3, and 53.8 mV dec-1 in 0.5 m H2 SO4 , 1.0 m PBS, and 1.0 m KOH, respectively, which could maintain 50 h of stable performance, almost outperforming all MoP-based catalysts reported so far. This study provides a valuable methodology to produce interacted multi-heteroatomic doped graphitic carbon-transition metal phosphide electrocatalysts with superior HER performance in a wide pH range.

19.
Artigo em Inglês | MEDLINE | ID: mdl-33253084

RESUMO

A taxonomic study was carried out on strain C16B3T, which was isolated from deep seawater of the Pacific Ocean. The bacterium was Gram-stain-negative, oxidase- and catalase- positive and rod-shaped. Growth was observed at salinities of 0-8.0 % and at temperatures of 10-45 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C16B3T belonged to the genus Solimonas, with the highest sequence similarity to Solimonas terrae KIS83-12T (97.2 %), followed by Solimonas variicoloris MN28T (97.0 %) and the other four species of the genus Solimonas (94.5 -96.8 %). The average nucleotide identity and estimated DNA-DNA hybridization values between strain C16B3T and the type strains of the genus Solimonas were 74.05-79.48 % and 19.5-22.5 %, respectively. The principal fatty acids (>5 %) were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c; 20.9 %), iso-C16 : 0 (14.6 %), C16 : 1 ω5c (9.4 %), iso-C12 : 0 (8.4 %), summed feature 2 (C14 : 0 3-OH/iso I-C16 : 1 and C12 : 0 aldehyde; 6.8 %) and C16 : 0 (5.5 %). The G+C content of the chromosomal DNA was 65.37 mol%. The respiratory quinone was determined to be Q-8 (100 %). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unidentified aminolipids, six unidentified phospholipids and one unidentified polar lipid. The combined genotypic and phenotypic data show that strain C16B3T represents a novel species within the genus Solimonas, for which the name Solimonas marina sp. nov. is proposed, with the type strain C16B3T (=MCCC 1A04678T=KCTC 52314T).


Assuntos
Gammaproteobacteria/classificação , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Gammaproteobacteria/isolamento & purificação , Hibridização de Ácido Nucleico , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Salinidade , Análise de Sequência de DNA , Ubiquinona/química
20.
Chem Soc Rev ; 49(24): 9220-9248, 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33165456

RESUMO

Rare earth (RE) elements are widely used in the luminescence and magnetic fields by virtue of their abundant 4f electron configurations. However, the overall performance and aqueous stability of single-component RE materials need to be urgently improved to satisfy the requirements for multifunctional applications. Carbon nanodots (CNDs) are excellent nanocarriers with abundant functional surface groups, excellent hydrophilicity, unique photoluminescence (PL) and tunable features. Accordingly, RE-CND hybrids combine the merits of both RE and CNDs, which dramatically enhance their overall properties such as luminescent and magnetic-optical imaging performances, leading to highly promising practical applications in the future. Nevertheless, a comprehensive review focusing on the introduction and in-depth understanding of RE-CND hybrid materials has not been reported to date. This review endeavors to summarize the recent advances of RE-CNDs, including their interaction mechanisms, general synthetic strategies and applications in fluorescence, biosensing and multi-modal biomedical imaging. Finally, we present the current challenges and the possible application perspectives of newly developed RE-CND materials. We hope this review will inspire new design ideas and valuable references in this promising field in the future.


Assuntos
Carbono/química , Meios de Contraste/química , Complexos de Coordenação/química , Corantes Fluorescentes/química , Metais Terras Raras/química , Pontos Quânticos/química , Animais , Técnicas Biossensoriais , Transferência Ressonante de Energia de Fluorescência , Humanos , Imageamento por Ressonância Magnética , Imagem Óptica , Propriedades de Superfície , Nanomedicina Teranóstica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA