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1.
Nanoscale Res Lett ; 14(1): 357, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784838

RESUMO

Metallic nanoplates have attracted widespread interests owing to their functional versatility, which relies heavily on their morphologies. In this study, the shape stability of several metallic nanoplates with body-centered-cubic (bcc) lattices is investigated by employing molecular dynamics simulations. It is found that the nanoplate with (110) surface planes is the most stable compared to the ones with (111) and (001) surfaces, and their shapes evolve with different patterns as the temperature increases. The formation of differently orientated facets is observed in the (001) nanoplates, which leads to the accumulation of shear stress and thus results in the subsequent formation of saddle shape. The associated shape evolution is quantitatively characterized. Further simulations suggest that the shape stability could be tuned by facet orientations, nanoplate sizes (including diameter and thickness), and components.

2.
J Biophotonics ; : e201900242, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31804752

RESUMO

Development of label-free methods for accurate classification of cells with high throughput can yield powerful tools for biological research and clinical applications. We have developed a deep neural network of DINet for extracting features from cross-polarized diffraction image (p-DI) pairs on multiple pixel scales to accurately classify cells in five types. A total of 6185 cells were measured by a polarization diffraction imaging flow cytometry (p-DIFC) method followed by cell classification with DINet on p-DI data. The averaged value and SD of classification accuracy were found to be 98.9% ± 1.00% on test data sets for 5-fold training and test. The invariance of DINet to image translation, rotation, and blurring has been verified with an expanded p-DI data set. To study feature-based classification by DINet, two sets of correctly and incorrectly classified cells were selected and compared for each of two prostate cell types. It has been found that the signature features of large dissimilarities between p-DI data of correctly and incorrectly classified cell sets increase markedly from convolutional layers 1 and 2 to layers 3 and 4. These results clearly demonstrate the importance of high-order correlations extracted at the deep layers for accurate cell classification.

3.
Sci Rep ; 9(1): 13212, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519996

RESUMO

Preeclampsia is a common cause of preterm birth and neonatal morbidity, but its relationship with neonatal respiratory distress syndrome (RDS) remains controversial. We conducted a retrospective cohort study with data from very-low-birth-weight (VLBW) infants born in 1997-2014 from the database of the Premature Baby Foundation of Taiwan to evaluate the relationship between maternal preeclampsia and neonatal RDS. In total, 13,490 VLBW infants were enrolled, including 2200 (16.3%) infants born to preeclamptic mothers. The mean (standard deviation) gestational ages were 30.7 (2.5) weeks in the preeclamptic group and 28.6 (2.9) weeks in the control (non-preeclamptic) group. Severe RDS was defined according to the surfactant therapy requirement. The incidence of severe RDS was lower in infants exposed to maternal preeclampsia than in controls [28.9% vs. 44%; odds ratio (OR), 0.52; 95% confidence interval (CI), 0.47-0.57]. However, after adjustment for confounders, the OR for severe RDS development in the preeclampsia group was 1.16 (95% CI, 1.02-1.31). Other factors, such as gestational age, birth weight, female sex, and antenatal receipt of two or more steroid doses were significantly protective against RDS in multivariate regression analysis. This study revealed that maternal preeclampsia slightly increases the risk of severe RDS in VLBW infants.

4.
J Am Chem Soc ; 141(24): 9731-9738, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31136166

RESUMO

Highly functionalized 4-aminoindoles were synthesized via the three-component cross-coupling of o-iodoaniline, N-benzoyloxyamines, and norbornadiene. The Catellani and retro-Diels-Alder strategy was used in this domino process. o-Iodoaniline, with electron-donating and sterically hindered protecting groups, made the reaction selective toward o-C-H amination. On the basis of density functional theory calculations, the intramolecular Buchwald coupling of this reaction underwent a dearomatization and a 1,3-palladium migration process. The reasons for the control of the chemical selectivity by the protecting groups are given. Moreover, synthetic applications toward 4-piperazinylindole and a GOT1 inhibitor were realized.

5.
Chem Commun (Camb) ; 54(10): 1185-1188, 2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29334093

RESUMO

This report describes a new method for three-component difluoroalkylation and trifluoromethylthiolation/trifluoromethylselenolation of π-bonds via air-stable SCF3 and SeCF3 reagents as free-radical initiators of ethyl iododifluoroacetate. ß-Proton elimination can be overcome effectively in this reaction system, and a broad substrate scope, including alkenes and alkynes, makes this approach practical and attractive.

6.
Phys Chem Chem Phys ; 19(47): 31796-31803, 2017 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-29170767

RESUMO

A traditional doping technique plays an important role in the band structure engineering of two-dimensional nanostructures. Since electron interaction is changed by doping, the optical and electrochemical properties could also be significantly tuned. In this study, density functional theory calculations have been employed to explore the structural stability, and electronic and optical properties of B-doped phosphorene. The results show that all B-doped phosphorenes are stable with a relatively low binding energy. Of particular interest is that these B-doped systems exhibit an indirect band gap, which is distinct from the direct one of pure phosphorene. Despite the different concentrations and configurations of B dopants, such indirect band gaps are robust. The screened hybrid density functional HSE06 predicts that the band gap of B-doped phosphorene is slightly smaller than that of pure phosphorene. Spatial charge distributions at the valence band maximum (VBM) and the conduction band minimum (CBM) are analyzed to understand the features of an indirect band gap. By comparison with pure phosphorene, B-doped phosphorenes exhibit strong anisotropy and intensity of optical absorption. Moreover, B dopants could enhance the stability of Li adsorption on phosphorene with less sacrifice of the Li diffusion rate. Our results suggest that B-doping is an effective way of tuning the band gap, enhancing the intensity of optical absorption and improving the performances of Li adsorption, which could promote potential applications in novel optical devices and lithium-ion batteries.

7.
J Chem Phys ; 147(15): 152717, 2017 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-29055341

RESUMO

Modern molecular-dynamics-based techniques are extremely powerful to investigate the dynamical evolution of materials. With the increase in sophistication of the simulation techniques and the ubiquity of massively parallel computing platforms, atomistic simulations now generate very large amounts of data, which have to be carefully analyzed in order to reveal key features of the underlying trajectories, including the nature and characteristics of the relevant reaction pathways. We show that clustering algorithms, such as the Perron Cluster Cluster Analysis, can provide reduced representations that greatly facilitate the interpretation of complex trajectories. To illustrate this point, clustering tools are used to identify the key kinetic steps in complex accelerated molecular dynamics trajectories exhibiting shape fluctuations in Pt nanoclusters. This analysis provides an easily interpretable coarse representation of the reaction pathways in terms of a handful of clusters, in contrast to the raw trajectory that contains thousands of unique states and tens of thousands of transitions.

8.
PLoS One ; 12(9): e0184726, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28886199

RESUMO

Morphological changes in apoptotic cells provide essential markers for defining and detection of apoptosis as a fundamental mechanism of cell death. Among these changes, the nuclear fragmentation and condensation have been regarded as the important markers but quantitative characterization of these changes is yet to be achieved. We have acquired confocal image stacks of 206 viable and apoptotic MCF-7 cells stained by three fluorescent dyes. Three-dimensional (3D) parameters were extracted to quantify and compare their differences in morphology. To analyze nuclear fragmentation, a new method has been developed to determine clustering of nuclear voxels in the reconstructed cells due to fluorescence intensity changes in nuclei of apoptotic cells. The results of these studies reveal that the 3D morphological changes in cytoplasm and nuclear membranes in apoptotic cells provide sensitive targets for label-free detection and staging of apoptosis. Furthermore, the clustering analysis and morphological data on nuclear fragmentation are highly useful for derivation of optical cell models and simulation of diffraction images to investigate light scattering by early apoptotic cells, which can lead to future development of label-free and rapid methods of apoptosis assay based on cell morphology.


Assuntos
Apoptose/fisiologia , Neoplasias da Mama/metabolismo , Apoptose/genética , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Fragmentação do DNA , Humanos , Células MCF-7 , Mitocôndrias/metabolismo
9.
J Phys Chem Lett ; 8(17): 4273-4278, 2017 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-28837772

RESUMO

Co-Pt and Co-Au core-shell nanoparticles were heated by molecular dynamics simulations to investigate their thermal stability. Two core structures, that is, hcp Co and fcc Co, have been addressed. The results demonstrate that the hcp-fcc phase transition happens in the hcp-Co-core/fcc-Pt-shell nanoparticle, while it is absent in the hcp-Co-core/fcc-Au-shell one. The stacking faults appear in both Pt and Au shells despite different structures of the Co core. The Co core and Pt shell concurrently melt and present an identical melting point in both Co-Pt core-shell nanoparticles. However, typical two-stage melting occurs in both Co-Au core-shell nanoparticles. Furthermore, the Au shell in the hcp-Co-core/fcc-Au-shell nanoparticle exhibits a lower melting point than that in the fcc-Co-core/fcc-Au-shell one, while the melting points are closely equal for both hcp and fcc Co cores. All of these observations suggest that their thermal stability strongly depends on the structure of the core and the element of the shell.

10.
ACS Appl Mater Interfaces ; 9(14): 12486-12493, 2017 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-28349693

RESUMO

Pt-Co bimetallic nanoparticles are promising candidates for Pt-based nanocatalysts and magnetic-storage materials. By using molecular dynamics simulations, we here present a detailed examination on the thermal stabilities of Pt-Co bimetallic nanoparticles with three configurations including chemically disordered alloy, ordered intermetallics, and core-shell structures. It has been revealed that ordered intermetallic nanoparticles possess better structural and thermal stability than disordered alloyed ones for both Pt3Co and PtCo systems, and Pt3Co-Pt core-shell nanoparticles exhibit the highest melting points and the best thermal stability among Pt-Co bimetallic nanoparticles, although their meltings all initiate at the surface and evolve inward with increasing temperatures. In contrast, Co-Pt core-shell nanoparticles display the worst thermal stability compared with the aforementioned nanoparticles. Furthermore, their melting initiates in the core and extends outward surface, showing a typical two-stage melting mode. The solid-solid phase transition is discovered in Co core before its melting. This work demonstrates the importance of composition distribution to tuning the properties of binary nanoparticles.

11.
Cell Physiol Biochem ; 41(2): 742-754, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28214842

RESUMO

BACKGROUND/AIM: Accumulation of advanced glycation end products (AGEs) is a major cause of diabetes mellitus (DM) skin complications. Methylglyoxal (MGO), a reactive dicarbonyl compound, is a crucial intermediate of AGEs generation. N-acetyl-L-cysteine (NAC), an active ingredient of some medicines, can induce endogenous GSH and hydrogen sulfide generation, and set off a condensation reaction with MGO. However, there is rare evidence to show NAC can alleviate DM-induced skin injury through inhibition of AGEs generation or toxicity. The present study aimed to observe the effects of NAC on MGO-induced inflammatory injury and investigate the roles of AGEs and its receptor (RAGE) in NAC's dermal protection in human HaCaT keratinocytes. METHODS: The cells were exposed to MGO to simulate a high MGO status in diabetic blood or tissues. The content of AGEs in serum or cell medium was measured with ELISA. The protective effects of NAC against MGO-induce injury were evaluated by administration before MGO one hour, in virtue of cell viability, mitochondrial membrane potential, inflammation reaction, nuclear factor (NF)-κB activation, matrix metalloproteinase (MMP)-9 expression, as well as cellular behavioral function. RESULTS: We found the AGEs levels of patients with DM were elevated comparing with healthy volunteers. The in vitro AGEs generation was also able to be enhanced by the exposure of HaCaT cells to MGO, which reduced dose-dependently cellular viability, damaged mitochondrial function, triggered secretion of interleukin (IL)-6 and IL-8, activated NF-κB and upregulated MMP-9 expression. Furthermore, the exposure caused cellular adhesion and migration dysfunction, as well as collagen type I inhibition. Importantly, before the exposure to MGO, the preconditioning with NAC significantly attenuated MGO-induced AGEs generation, improved cellular viability and mitochondrial function, partially reversed the overexpression of proinflammatory factors and MMP-9, as well as the activation of NF-κB. Lastly, NAC blocked MGO-induced RAGE upregulation, and inhibition of RAGE with its neutralizing antibody significantly alleviated MGO-induced NF-κB activation, MMP-9 upregulation and inflammatory injury in HaCaT cells. CONCLUSION: The present work indicates the administration of NAC can prevent MGO-induced dermal inflammatory injury through inhibition of AGEs/RAGE signal, which may provide a basal support for the treatment of diabetic skin complications with NAC-containing medicines in the future.


Assuntos
Acetilcisteína/farmacologia , Produtos Finais de Glicação Avançada/análise , Substâncias Protetoras/farmacologia , Aldeído Pirúvico/farmacologia , Receptor para Produtos Finais de Glicação Avançada/análise , Regulação para Cima/efeitos dos fármacos , Idoso , Estudos de Casos e Controles , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Feminino , Produtos Finais de Glicação Avançada/sangue , Humanos , Interleucina-6/análise , Interleucina-8/análise , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Receptor para Produtos Finais de Glicação Avançada/sangue
12.
ACS Appl Mater Interfaces ; 8(34): 22175-81, 2016 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-27487298

RESUMO

The rapid development of electronic products has inspired scientists to design and explore novel electrode materials with an ultrahigh rate of charging/discharging capability, such as two-dimensional (2-D) nanostructures of graphene and MoS2. In this study, another 2-D nanosheet, that is a borophene layer, has been predicted to be utilized as a promising anode material for high-performance Li ion battery based on density functional theory calculations. Our study has revealed that Li atom can combine strongly with borophene surface strongly and easily, and exist as a pure Li(+) state. A rather small energy barrier (0.007 eV) of Li diffusion leads to an ultrahigh diffusivity along an uncorrugated direction of borophene, which is estimated to be 10(4) (10(5)) times faster than that on MoS2 (graphene) at room temperature. A high Li storage capacity of 1239 mA·h/g can be achieved when Li content reaches 0.5. A low average operating voltage of 0.466 V and metallic properties result in that the borophene can be used as a possible anode material. Moreover, the properties of Li adsorption and diffusion on the borophene affected by Ag (111) substrate have been studied. It has been found that the influence of Ag (111) substrate is very weak. Li atom can still bind on the borophene with a strong binding energy of -2.648 eV. A small energy barrier of 0.033 eV can be retained for Li diffusion along the uncorrugated direction, which can give rise to a high Li diffusivity. Besides, the performances of borophene-based Na ion battery have been explored. Our results suggest that an extremely high rate capability could be expected in borophene-based Li ion battery.

13.
Phys Chem Chem Phys ; 18(25): 17010-7, 2016 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-27297782

RESUMO

Bimetallic nanoparticles comprising noble metal and non-noble metal have attracted intense interest over the past few decades due to their low cost and significantly enhanced catalytic performances. In this article, we have explored the atomic structure and thermal stability of Pt-Fe alloy and core-shell nanoparticles by molecular dynamics simulations. In Fe-core/Pt-shell nanoparticles, Fe with three different structures, i.e., body-centered cubic (bcc), face-centered cubic (fcc), and amorphous phases, has been considered. Our results show that Pt-Fe alloy is the most stable configuration among the four types of bimetallic nanoparticles. It has been discovered that the amorphous Fe cannot stably exist in the core and preferentially transforms into the fcc phase. The phase transition from bcc to hexagonal close packed (hcp) has also been observed in bcc-Fe-core/Pt-shell nanoparticles. In contrast, Fe with the fcc structure is the most preferred as the core component. These findings are helpful for understanding the structure-property relationships of Pt-Fe bimetallic nanoparticles, and are also of significance to the synthesis and application of noble metal based nanoparticle catalysts.

14.
Phys Chem Chem Phys ; 18(14): 9847-54, 2016 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-27003035

RESUMO

Atomic-scale understanding of structures and thermodynamic stability of core-shell nanoparticles is important for both their synthesis and application. In this study, we systematically investigated the structural stability and thermodynamic evolution of core-shell structured Pd-Ni nanoparticles by molecular dynamics simulations. It has been revealed that dislocations and stacking faults occur in the shell and their amounts are strongly dependent on the core/shell ratio. The presence of these defects lowers the structural and thermal stability of these nanoparticles, resulting in even lower melting points than both Pd and Ni monometallic nanoparticles. Furthermore, different melting behaviors have been disclosed in Pd-core/Ni-shell and Ni-core/Pd-shell nanoparticles. These diverse behaviors cause different relationships between the melting temperature and the amount of stacking faults. Our results display direct evidence for the tunable stability of bimetallic nanoparticles. This study provides a fundamental perspective on core-shell structured nanoparticles and has important implications for further tailoring their structural and thermodynamic stability by core/shell ratio or composition controlling.

15.
Phys Chem Chem Phys ; 18(4): 3097-102, 2016 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-26741266

RESUMO

ZnO/GaN alloys have exceptional photocatalytic applications owing to their suitable band gaps corresponding to the range of visible light wavelength and thus have attracted extensive attention over the past few years. In this study, the structural stabilities and electronic properties of core/shell, biaxial, and super-lattice ZnO/GaN heterostructured nanowires have been investigated by means of first-principles calculations based on the density functional theory. The effects of the nanowire size, the GaN ratio, and strain have been explored. It is found that all studied heterostructured nanowires are less stable than pure ZnO nanowires, exhibiting larger sized wires with better structural stabilities and inversely proportional relationship between structural stability and the GaN ratio. Electronic band structures imply that all heterostructured nanowires are semiconductors with the band gaps strongly depending on the GaN ratios as well as mechanical strain. Particularly, for the biaxial and the super-lattice nanowires, their band gaps decrease firstly and then increase with the increasing GaN ratios. Electronic contributions to the valence band maximum (VBM) and the conduction band minimum (CBM) are discussed for exploiting the potential photocatalytic applications.

16.
Phys Chem Chem Phys ; 17(8): 5751-7, 2015 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-25628229

RESUMO

Nanosized noble metallic particles enclosed by high-index facets exhibit superior catalytic activity because of their high density of low-coordinated step atoms at the surface, and thus have attracted growing interest over the past decade. In this article, we employed molecular dynamics simulations to investigate the thermodynamic evolution of tetrahexahedral Rh nanoparticles respectively covered by {210}, {310}, and {830} facets during the heating process. Our results reveal that the {210} faceted nanoparticle exhibits better thermal and shape stability than the {310} and {830} faceted ones. Meanwhile, because the {830} facet consists of {210} and {310} subfacets, the stability of the {830} faceted Rh nanoparticle is dominated by the {310} subfacet, which possesses a relatively poor stability. Furthermore, the shape transformation of these nanoparticles occurs much earlier than their melting. Further analyses indicate that surface atoms with higher coordination numbers display lower surface diffusivity, and are thus more helpful for stabilizing the particle shape. This study offers an atomistic understanding of the thermodynamic behaviors of high-index-faceted Rh nanoparticles.

17.
Arch Gynecol Obstet ; 291(6): 1289-96, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25424899

RESUMO

OBJECTIVE: The aim of this study was to evaluate the expression of DACT1 in human placenta tissue and the relationship between DACT1 and target genes of the Wnt signaling pathway. METHOD: Real-time PCR and western blotting were used to detect the expression of DACT1 and the target genes of Wnt signaling pathway in human placenta tissue. And the relationship between them was analyzed using SPSS 19. RESULTS: Real-time PCR results showed that DACT1 expression was significantly higher in 49- to 71-day placenta tissues (mean value = 0.020) than that in 39- to 48-day (the mean value = 0.009). The mRNA expressions of the Wnt signaling pathway target genes, CCND1, CCND2, FOSL1, DAB2 and JUN, were also increased expressed in human placenta tissues. Significant positive associations between DACT1 and CCND1, CCND2, FOSL1, DAB2 and JUN were observed. Western blotting analysis showed that the protein expression of DACT1, CCND1, CCND2, FOSL1, DAB2 and JUN displayed the increasing trend in 43-, 49- and 71-day placenta samples. CONCLUSION: DACT1 might play an important role in human placenta development via promoting Wnt signaling.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Nucleares/metabolismo , Placentação/genética , RNA Mensageiro/genética , Via de Sinalização Wnt/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Adulto , Western Blotting , Feminino , Humanos , Placenta/metabolismo , Placentação/fisiologia , Gravidez , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais
18.
Sci Rep ; 4: 7051, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25394424

RESUMO

Introducing hollow structures into metallic nanoparticles has become a promising route to improve their catalytic performances. A fundamental understanding of thermal stability of these novel nanostructures is of significance for their syntheses and applications. In this article, molecular dynamics simulations have been employed to offer insights into the thermodynamic evolution of hollow bimetallic core-shell nanoparticles. Our investigation reveals that for hollow Pt-core/Au-shell nanoparticle, premelting originates at the exterior surface, and a typical two-stage melting behavior is exhibited, similar to the solid ones. However, since the interior surface provides facilitation for the premelting initiating at the core, the two-stage melting is also observed in hollow Au-core/Pt-shell nanoparticle, remarkably different from the solid one. Furthermore, the collapse of hollow structure is accompanied with the overall melting of the hollow Pt-core/Au-shell nanoparticle while it occurs prior to that of the hollow Au-core/Pt-shell nanoparticle and leads to the formation of a liquid-core/solid-shell structure, although both of them finally transform into a mixing alloy with Au-dominated surface. Additionally, the existence of stacking faults in the hollow Pt-core/Au-shell nanoparticle distinctly lowers its melting point. This study could be of great importance to the design and development of novel nanocatalysts with both high activity and excellent stability.

19.
Phys Chem Chem Phys ; 16(41): 22754-61, 2014 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-25234428

RESUMO

A microscopic understanding of the thermal stability of metallic core-shell nanoparticles is of importance for their synthesis and ultimately application in catalysis. In this article, molecular dynamics simulations have been employed to investigate the thermodynamic evolution of Au-CuPt core-shell trimetallic nanoparticles with various Cu/Pt ratios during heating processes. Our results show that the thermodynamic stability of these nanoparticles is remarkably enhanced upon rising Pt compositions in the CuPt shell. The melting of all the nanoparticles initiates at surface and gradually spreads into the core. Due to the lattice mismatch among Au, Cu and Pt, stacking faults have been observed in the shell and their numbers are associated with the Cu/Pt ratios. With the increasing temperature, they have reduced continuously for the Cu-dominated shell while more stacking faults have been produced for the Pt-dominated shell because of the significantly different thermal expansion coefficients of the three metals. Beyond the overall melting, all nanoparticles transform into a trimetallic mixing alloy coated by an Au-dominated surface. This work provides a fundamental perspective on the thermodynamic behaviors of trimetallic, even multimetallic, nanoparticles at the atomistic level, indicating that controlling the alloy composition is an effective strategy to realize tunable thermal stability of metallic nanocatalysts.

20.
Angew Chem Int Ed Engl ; 53(20): 5097-101, 2014 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-24692362

RESUMO

Noble metal nanocrystals (NCs) enclosed with high-index facets hold a high catalytic activity thanks to the high density of low-coordinated step atoms that they exposed on their surface. Shape-control synthesis of the metal NCs with high-index facets presents a big challenge owing to the high surface energy of the NCs, and the shape control for metal Rh is even more difficult because of its extraordinarily high surface energy in comparison with Pt, Pd, and Au. The successful synthesis is presented of tetrahexahedral Rh NCs (THH Rh NCs) enclosed by {830} high-index facets through the dynamic oxygen adsorption/desorption mediated by square-wave potential. The results demonstrate that the THH Rh NCs exhibit greatly enhanced catalytic activity over commercial Rh black catalyst for the electrooxidation of ethanol and CO.

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