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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 317: 124405, 2024 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-38718746

RESUMEN

With the expansion of the application of high-sensitivity Surface-enhanced Raman scattering (SERS) technique, micro SERS-active substrates with rich optical properties and high-level functions are desired. In this study, silver nanorings with nanoscale surface roughness were fabricated as a new type of enclosed quasi-2D micro-SERS-active substrate. Highly-crystalline spherical and hemispherical silver nanoprotrusions were densely and uniformly distributed over the entire surface of the nanorings. The SERS signals were significantly enhanced on the roughened silver nanorings which were mainly derived from the maximal localized surface plasmon resonance (LSPR) points at the junctions between adjacent coupled nanoprotrusions on the roughened nanorings. The mapping image shows a uniform and intense LSPR enhancement over the nanorings, owing to the uniform and dense distribution of silver nanoprotrusions and the resulting uniform distribution of maximal LSPR points on the roughened nanorings. The dark-field spectra further indicated that the single roughened silver nanoring had significant LSPR enhancement, a wide LSPR frequency-range response, and adaptability for SERS enhancement. Notably, both the measured and simulated results demonstrate that the maximal LSPR enhancement at the junctions between the nanoprotrusions, which are distributed on the inner surface of the silver nanoring, is higher than that on the outer surface because of the plasmon-focusing effect of the enclosed silver nanoring, which leads to the lateral asymmetrical distribution of LSPR intensity, indicating more LSPR and SERS features. These results indicate that single roughened silver nanorings exhibit excellent performance as a new type of enclosed quasi-2D silver nanoring micro-SERS-active substrate, microzone LSPR catalysis, and micro/nanodevices.

2.
Opt Express ; 32(6): 9105-9115, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38571151

RESUMEN

The strong interaction between light and matter is one of the current research hotspots in the field of nanophotonics, and provides a suitable platform for fundamental physics research such as on nanolasers, high-precision sensing in biology, quantum communication and quantum computing. In this study, double Rabi splitting was achieved in a composite structure monolayer MoS2 and a single Ag@Au hollow nanocube (HNC) in room temperature mainly due to the two excitons in monolayer MoS2. Moreover, the tuning of the plasmon resonance peak was realized in the scattering spectrum by adjusting the thickness of the shell to ensure it matches the energy of the two excitons. Two distinct anticrossings are observed at both excitons resonances, and large double Rabi splittings (90 meV and 120 meV) are obtained successfully. The finite-difference time domain (FDTD) method was also used to simulate the scattering spectra of the nanostructures, and the simulation results were in good agreement with the experimental results. Additionally, the local electromagnetic field ability of the Ag@Au hollow HNC was proved to be stronger by calculating and comparing the mode volume of different nanoparticles. Our findings provides a good platform for the realization of strong multi-mode coupling and open up a new way to construct nanoscale photonic devices.

3.
J Ethnopharmacol ; 328: 118124, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38556138

RESUMEN

ETHNOPHAMACOLOGICAL RELEVANCE: Morinda officinalis oligosaccharides (MOs) is a mixture of oligosaccharides extracted from the roots of Morinda officinalis (MO). It is approved by Chinese Food and Drug Administration (CFDA) for depression treatment. MOs could improve the antidepressant efficacy of escitalopram in clinic. AIM OF THE STUDY: We aim to explore the antidepressant activity and potential mechanism of the combination usage of MOs and escitalopram on animal model of depression. MATERIALS AND METHODS: Depressive animal model was induced by chronic mild stress (CMS). Behavioral tests were conducted to evaluate the antidepressant efficacy of MOs and escitalopram. Serum neurotransmitter levels were detected by High-performance liquid chromatography (HPLC). Quantitative real-time PCR and Western blotting were applied to assay the hippocampus neurotrophic factors' mRNA and protein levels. Peripheral cytokines levels were measured through Enzyme-Linked Immunosorbent Assay (ELISA). Micorglia polization phenotype was assayed by immunofluorescence and flow cytometry. RESULTS: MOs and escitalopram obviously attenuated depression-like behaviors of CMS mice. Importantly, MOs plus escitalopram exhibited better antidepressant activity on CMS mice than monotherapy. At the same time, MOs combined escitalopram treatment significantly increased hippocampus neurotransmitters and neurotrophic factor levels, stimulated hippocampus neurogenesis and relieved central nervous system (CNS) microglia over-activation of CMS mice. The combination therapy had greater effect on neuroprotection and inflammation attenuation of CMS mice than monotherapy. CONCLUSION: Our results indicates MOs combined escitalopram might produce antidepressant activity through protecting neuron activity, relieving inflammation and modulating microglia polarization process.


Asunto(s)
Escitalopram , Morinda , Ratones , Animales , Depresión/tratamiento farmacológico , Antidepresivos/farmacología , Antidepresivos/uso terapéutico , Oligosacáridos/farmacología , Oligosacáridos/uso terapéutico , Inflamación/tratamiento farmacológico , Estrés Psicológico/tratamiento farmacológico , Modelos Animales de Enfermedad
4.
Artículo en Inglés | MEDLINE | ID: mdl-38172979

RESUMEN

BACKGROUND: Self-harm, a severe mental health concern among children and adolescents, has varying global prevalence rates. Previous studies have suggested potential associations between specific behavioral aspects of biological rhythm and self-harm risk in these populations. OBJECTIVE: Our study aimed to elucidate the relationship between biological rhythm patterns and the propensity of self-harm among Chinese children and adolescents using the Baoxing Youth Mental Health (BYMH) cohort. METHODS: We included 1883 Chinese children and adolescents from the BYMH cohort. The self-report questions used to assess biological rhythm and self-harm. We applied Principal Component Analysis (PCA) to distinguish patterns of biological rhythms. Logistic regression models were conducted to estimate the associations between biological rhythm, as well as biological rhythm patterns and risk of self-harm. RESULTS: Of the participants, 35.0% reported experiencing lifetime self-harm. PCA revealed six significantly predominant biological rhythm patterns. Elevated risks of self-harm were linked with unhealthy eating practices, daytime tiredness, and unhealthy bedtime snacking. Conversely, patterns emphasizing physical exercise, family meals for breakfast, and nutritious diet exhibited decreased self-harm propensities. These trends persisted across varied self-harm attributes, including type, recency, and frequency of self-harm. CONCLUSIONS: This study underscores the critical impact of biological rhythms on self-harm risks among Chinese youth. Targeted lifestyle interventions, focusing on improved sleep and dietary habits, could serve as potent preventive measures. Our findings lay the groundwork for future longitudinal studies to further probe these associations, fostering the creation of tailored interventions to curb self-harm and enhance mental well-being in younger populations.

5.
Dalton Trans ; 53(6): 2442-2449, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38229516

RESUMEN

Exploring efficient and low-cost oxygen evolution reaction (OER) electrocatalysts reaching the industrial level current density is crucial for hydrogen production via water electrolysis. In this feature article, we summarize the recent progress in hierarchical nanostructures for the industrial-level OER. The contents mainly concern (i) the design of a hierarchical structure; (ii) a Ni-based hierarchical structure for the industrial current density OER; and (iii) the surface reconstruction of the hierarchical structure during the OER process. The work provides valuable guidance and insights for the manufacture of hierarchical nanomaterials and devices for industrial applications.

6.
Front Med (Lausanne) ; 10: 1140787, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37265489

RESUMEN

Background: Intimate partner violence (IPV) has been associated with an elevated risk of multiple adverse birth outcomes, yet little is known about how specific IPV influences adverse birth outcomes. The aim of this study was to examine the association between IPV during pregnancy and adverse birth outcomes (i.e., preterm birth, low birth weight, and stillbirth). Methods: Systematic searches were conducted using four databases: EMBASE, Web of Science, PubMed, and CINAHL for observational studies published from 1 January 2011 to 31 August 2021. Two reviewers independently carried out the literature search, study selection, data extraction, assessment of the study, and risk of bias assessment; disagreements were resolved by a third reviewer. A random-effect model was used to calculate the odds ratio (OR) with a 95% confidence interval (CI) for preterm birth, low birth weight, and stillbirth. I2 statistic accompanied by chi-square p-value was used to assess heterogeneity, and funnel plot and Peter's test were used to assess publication bias. Results: In total, 23 studies met the inclusion criterion. IPV was associated with preterm birth (OR = 1.84; 95% CI: 1.37-2.49; I2 = 88%), low birth weight (OR = 2.73; 95% CI: 1.66-4.48; I2 = 95%), and stillbirth (OR = 1.74; 95% CI: 0.86-3.54; I2 = 64%). We attained comparable results among all specific IPV including physical, sexual, emotional, and mixed. Conclusion: Intimate partner violence and specific IPV during pregnancy were significantly associated with adverse birth outcomes, especially for physical IPV. An urgent need for greater action to prevent or intervene in IPV during pregnancy is warranted. Systematic review registration: CRD42021282936, https://www.crd.york.ac.uk/prospero/.

7.
Dalton Trans ; 52(20): 6860-6869, 2023 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-37157968

RESUMEN

The design and synthesis of cost-effective and stable bifunctional electrocatalysts for water splitting via a green and sustainable fabrication way remain a challenging problem. Herein, a bio-inspired method was used to synthesize NiFeP nanoparticles embedded in (N,P) co-doped carbon with the added carbon nanotubes. The obtained Ni0.8Fe0.2P-C catalyst displayed excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances in both alkaline and alkaline simulated seawater solutions. The optimal Ni0.8Fe0.2P-C/NF only needs overpotentials of 45 and 242 mV to reach the current density of 10 mA cm-2 under HER and OER working conditions in 1.0 M KOH solution, respectively. First-principles calculations revealed the presence of a strong interaction between the carbon layer and metal phosphide nanoparticles. Benefiting from this and carbon nanotubes modification, the fabricated Ni0.8Fe0.2P-C presents impressive stability, working continuously for 100 h without collapse. A low alkaline cell voltage of 1.56 V for the assembled Ni0.8Fe0.2P-C/NF//Ni0.8Fe0.2P-C/NF electrocatalyzer could afford a current density of 10 mA cm-2. Moreover, when integrated with a photovoltaic device, the bifunctional Ni0.8Fe0.2P-C electrocatalyst demonstrates application potential for sustainable solar-driven water electrolysis.

8.
Lifetime Data Anal ; 29(3): 628-653, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36862277

RESUMEN

The case-cohort design was developed to reduce costs when disease incidence is low and covariates are difficult to obtain. However, most of the existing methods are for right-censored data and there exists only limited research on interval-censored data, especially on regression analysis of bivariate interval-censored data. Interval-censored failure time data frequently occur in many areas and a large literature on their analyses has been established. In this paper, we discuss the situation of bivariate interval-censored data arising from case-cohort studies. For the problem, a class of semiparametric transformation frailty models is presented and for inference, a sieve weighted likelihood approach is developed. The large sample properties, including the consistency of the proposed estimators and the asymptotic normality of the regression parameter estimators, are established. Moreover, a simulation is conducted to assess the finite sample performance of the proposed method and suggests that it performs well in practice.


Asunto(s)
Modelos Estadísticos , Humanos , Funciones de Verosimilitud , Simulación por Computador , Análisis de Regresión , Estudios de Cohortes
9.
Stat Med ; 42(14): 2293-2310, 2023 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-36999548

RESUMEN

Length-biased data occur often in many scientific fields, including clinical trials, epidemiology surveys and genome-wide association studies, and many methods have been proposed for their analysis under various situations. In this article, we consider the situation where one faces length-biased and partly interval-censored failure time data under the proportional hazards model, for which it does not seem to exist an established method. For the estimation, we propose an efficient nonparametric maximum likelihood method by incorporating the distribution information of the observed truncation times. For the implementation of the method, a flexible and stable EM algorithm via two-stage data augmentation is developed. By employing the empirical process theory, we establish the asymptotic properties of the resulting estimators. A simulation study conducted to assess the finite-sample performance of the proposed method suggests that it works well and is more efficient than the conditional likelihood approach. An application to an AIDS cohort study is also provided.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida , Modelos Estadísticos , Humanos , Funciones de Verosimilitud , Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida/epidemiología , Estudios de Cohortes , Estudio de Asociación del Genoma Completo , Análisis de Regresión , Simulación por Computador
10.
Adv Mater ; 35(12): e2211177, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36606317

RESUMEN

An efficient NiSx -modified ß-Ni(OH)2 electrode is reported for the selective oxidation reaction of 5-hydroxymethylfurfural (HMFOR) with excellent electrocatalytic 5-hydroxymethylfurfural (HMF) selectivity (99.4%), conversion (97.7%), and Faradaic efficiency (98.3%). The decoration of NiSx will evoke high-valence Ni2+ δ species in the reconstructed ß-Ni(OH)2 electrode, which are the real active species for HMFOR. The generated NiSx /Ni(OH)O modulates the proton-coupled electron-transfer (PCET) process of HMFOR, where the electrocatalytically generated Ni(OH)O can effectively trap the protons from the CHO end in HMF to realize electron transfer. The oxygen evolution reaction (OER) competes with the HMFOR when NiSx /Ni(OH)O continues to accumulate, to generate the NiSx /NiOx (OH)y intermediate. Density functional theory (DFT) calculations and experimental results verify that the adsorption energy of HMF can be optimized through the increased NiSx composition for more efficient capture of protons and electrons in the HMFOR.

11.
J Mol Model ; 29(2): 41, 2023 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-36648609

RESUMEN

Single-atom catalysts (SACs) in heterogeneous catalysts have attracted increasing attention and the adsorption and nucleation of single atom on the surface are closely related to the performance of the catalyst. The present work employed density functional theory calculations to examine the adsorption of single Au atom and nucleation on γ-Al2O3 surfaces at the atomic level. The effect of surface hydroxyls group on the adsorption and nucleation of single Au atom on γ-Al2O3 surfaces is explored. It was found that the spillover reactions of surface hydroxyls H atoms with the deposited Au- are not available on the hydroxylated surface. The interaction of Au to the clean surface is the stronger than to the hydroxylated surface. The even-odd alternations of Aux and weak binding of single Au atoms to γ-Al2O3 leads to large even-numbered Au cluster on the surface. Density of states and electron density difference analysis show that the electronic structure of Au/γ-Al2O3 is quite different from the reported Cu and Pd on Al2O3.

12.
Nanotechnology ; 34(13)2023 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-36595301

RESUMEN

As a significant accompanying phenomenon of surface-enhanced Raman scattering (SERS), the addition of foreign molecules to colloidal gold or silver nanoparticles results in a new abnormal optical absorption (AOA) band, which usually appears in the long-wavelength region. The assignment of this AOA band has long been debated as an important issue that is desired to be addressed in the SERS field, which is crucial for a clear understanding of the SERS enhancement mechanism and beneficial to surface plasmonics. In this study, both the calculated and measured optical absorptions of gold nanoparticle monomers and dimers as well as their interactions with adsorbed molecules, showed that the AOA band in the long-wavelength region which was assigned to the characteristic longitudinal localized surface plasmon resonance (LSPR) effect of gold nanoparticle chain aggregates in conventional SERS electromagnetic theory, should be attributed to the charge-transfer resonance absorption from gold nanoparticles to adsorbed molecules. This was further confirmed by the corresponding SERS effects. As the excitation wavelength at 785 nm was resonant with the broad AOA band centered at 750 nm, the SERS peaks of the adsorbed pyridine molecules could be dramatically enhanced due to the charge-transfer resonance effect. In contrast, under an excitation wavelength of 532 nm, the SERS peaks appeared very weak, although the excitation wavelength was resonant with the LSPR absorption band of the individual gold nanoparticles.

13.
Dalton Trans ; 51(41): 15863-15872, 2022 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-36193644

RESUMEN

N-doped graphene with nano-sized holes possesses abundant electrochemically active sites at the exposed edge and an open porous structure, leading to a better electrochemical performance and faster electron and ion transport than the basal planes in graphene. In this study, three-dimensional graphene with a porous structure and abundant doped N (3d-NHG) were synthesized as bifunctional electrodes for methyl parathion (MP) detection and supercapacitors. The roles of N-doping and the holey construction in the electrochemical performance of the 3d-NHG were systematically investigated through a combined theory-experiment strategy. The 3d-NHG-based electrochemical sensor successfully detected methyl parathion in the range of 38 nm-380 µM with a low detection limit (2.27 nM) and superior sensitivity. Furthermore, the 3d-NHG also demonstrated potential for use in supercapacitors with a specific capacitance of 207 F g-1 at 1 A g-1 and excellent rate capability (76% capacitance retention at 10 A g-1). Density functional theory calculations revealed that the exposed carbon sites at the edge are the reactive sites for species adsorption. Moreover, the holey structure in 3d-NHG plays a dominating role in electrochemical processes and in the enhanced electrocatalysis. This work provides guidance for the rational design of high-performance bifunctional electrodes for MP detection and supercapacitors by defect engineering.

14.
Front Pharmacol ; 13: 855964, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36052143

RESUMEN

Morinda officinalis oligosaccharides (MOs) are natural herbal extracts that have been shown to exert antidepressant effects. However, the mechanism of this effect remains unclear. Here, we explored the mechanism by which MOs improved experimental depression. Using a chronic mild stress (CMS) murine model, we examined whether MOs could protect against depressive-like behaviour. Lipopolysaccharide (LPS)- and ATP-treated BV2 cells were used to examine the potential mechanism by which MOs mediate the inflammatory response. We found that MOs prevented the CMS-induced reduction in the sucrose preference ratio in the sucrose preference test (SPT) and shortened the immobility durations in both the tail suspension test (TST) and forced swim test (FST). We also noticed that MOs suppressed inflammatory effects by deactivating the MyD88/PI3K pathway via E2F2 in CMS mice or LPS- and ATP-stimulated BV2 cells. Furthermore, overexpression of E2F2 blunted the beneficial effects of MOs in vitro. Collectively, these data showed that MOs exerted antidepressant effects in CMS mice by targeting E2F2-mediated MyD88/PI3K signalling pathway.

15.
Dalton Trans ; 51(38): 14517-14525, 2022 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-36070498

RESUMEN

Preparing low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction using a simple strategy still faces challenges. In this work, we proposed a facile phosphating process to successfully transform CoFe-BTC (BTC = 1,3,5-benzenetricarboxylate) precursors into carbon-incorporated bimetallic phosphide (CoFe-P/C) nanospheres. Due to the synergistic effect between bimetals and uniformly covered carbon shells outside, the as-synthesized porous bimetallic phosphide nanospheres exhibit superior HER activity, enhanced kinetics, and excellent cycle durability in both acidic and alkaline solutions. The optimized material could afford a current density of 10 mA cm-2 with overpotentials of 138 and 193 mV for the HER in acidic and alkaline solutions, respectively. Meanwhile, it delivered small Tafel slopes of 84 and 78 mV dec-1 for the HER in 0.5 M H2SO4 and 1.0 M KOH, respectively. Moreover, an assembled alkaline electrolyzer enabled a low voltage of 1.62 V to drive a current density of 10 mA cm-2 for overall water splitting. DFT calculations indicate that the CoP-Fe2P composite is supposed to exhibit better HER performance than each component, revealing the vital role of the interfacial site in catalyzing the HER.

16.
Plant Direct ; 6(7): e418, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35865074

RESUMEN

MicroRNAs (miRNAs) are types of endogenous non-coding small RNAs found in eukaryotes that are 18-25 nucleotides long. miRNAs are considered to be key regulatory factors of the expression of target mRNA. The roles of miRNAs involved in the regulation of anthocyanin accumulation in pigmented potatoes have not been systematically reported. In this study, the differentially expressed miRNAs and their target genes involved in the accumulation of anthocyanin during different developmental stages in purple potato (Solanum tuberosum L.) were identified using small RNA (sRNA) and degradome sequencing. A total of 275 differentially expressed miRNAs were identified in the sRNA libraries. A total of 69,387,200 raw reads were obtained from three degradome libraries. The anthocyanin responsive miRNA-mRNA modules were analyzed, and 37 miRNAs and 23 target genes were obtained. Different miRNAs regulate the key enzymes of anthocyanin synthesis in purple potato. The structural genes included phenylalanine ammonia lyase, chalcone isomerase, flavanone 3-hydroxylase, and anthocyanidin 3-O-glucosyltransferase. The regulatory genes included WD40, MYB, and SPL9. stu-miR172e-5p_L-1R-1, stu-miR828a, stu-miR29b-4-5p, stu-miR8019-5p_L-4R-3, stu-miR396b-5p, stu-miR5303f_L-7R + 2, stu-miR7997a_L-3, stu-miR7997b_L-3, stu-miR7997c_L + 3R-5_2ss2TA3AG, stu-miR156f-5p_L + 1, stu-miR156a, stu-miR156a_R-1, stu-miR156e, stu-miR858, stu-miR5021, stu-miR828 and their target genes were validated by qRT-PCR. They play important roles in the coloration and accumulation of purple potatoes. These results provide new insights into the biosynthesis of anthocyanins in pigmented potatoes.

17.
Spectrochim Acta A Mol Biomol Spectrosc ; 281: 121607, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-35841859

RESUMEN

The plasma exciton induced photocatalytic reaction has considerable potential in terms of controllability and selectivity. In this paper, with the advantage of Raman fingerprinting, the localized photocatalytic reaction driven by surface plasmons is realized by the writing and reading process of encrypted information at the micro/nano scale. A layer of probe molecules (4-nitrobenzenethiol, 4-NBT) was assembled on a gold nanoporous array grown on porous anodic aluminium oxide (AAO) membranes. The focused Raman spot is manipulated in a two-dimensional micro/nano manipulation technique to control the movement of the spot at an excitation wavelength of 633 nm. Probe molecules within the spot trajectory will undergo a photocatalytic reaction to produce p,p'-dimercaptoazobenzene (DMAB) molecules, thereby writing the specific information required. The use of Raman mapping to image the characteristic peaks of formed DMAB under excitation light with a longer wavelength of 785 nm enables the readout of 2D micro/nano cryptograms. Combined with finite-difference time-domain (FDTD) simulations, it was found that the presence of a large number of regularly arranged hot spots on the surface of the array is the key to achieving the efficient photocatalytic reaction. This study enables real-time, lossless recording/reading of encrypted information with the aid of 2D Raman technology. This would be a very interesting research area with broad application in confidential information storage.

18.
Dalton Trans ; 51(27): 10420-10431, 2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35762394

RESUMEN

The systematic atomistic level investigation of low-index surface structures, stabilities, and catalytic performances of CoP and FeCoP2 towards the O2 reduction reaction (ORR) is vital for their applications. Employing first-principles calculations, it is revealed that CoP and FeCoP2 present the same surface stability in the order of (101) ≈ (011) > (111) > (001) > (110) > (010) > (100). They also possess a similar Wulff equilibrium crystal shape with (101) and (011) exposing the largest surface area. From the electronic view, FeCoP2 presents improved electronic conductivity compared with CoP. From the energy view, whether FeCoP2 delivers improved electrocatalytic activity toward the ORR with respect to CoP depends on the reactive surfaces and sites. Among the 4 surfaces considered, only CoP(101), FeCoP2(101) and FeCoP2(011) delivered ORR performances theoretically when the bridge metal-metal site acts as the reactive center, which makes CoP(011) the only exception. CoP(101)-bCo-Co and FeCoP2(011)-bFe-Co exhibit a larger thermodynamic limiting potential than FeCoP2(101)-bCo-Co, suggesting their higher performances toward the ORR. The last step of HO* desorption as the rate-limiting step accounts for 3/4. The third step of transformation from O* to HO* as the most sluggish step accounts for 1/4. The work function, d-band center, Bader charge, and electronic localization function calculations are performed to reveal the HO adsorption nature. The present work provides fundamental insight into the effect of Fe doping into CoP, the determination of the catalyst surface and the key species adsorption nature to guide the rational design of high-performance materials.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 279: 121380, 2022 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-35636133

RESUMEN

Plasma-driven photocatalytic reactions have great research value in the fields of energy utilization, environmental pollution treatment and micro-nano information encryption. In most cases, the substrates used to study photocatalytic reactions are dispersed and disordered, which leads to poor signal reproducibility and makes it difficult to realize applications in the field of quantitative analysis. In this paper, two different sizes of polystyrene (PS) microspheres were used as templates to prepare gold microsphere arrays (Au MA) with homogeneous particle size and regular arrangement. The p-Aminothiophenol (PATP) was selected as the probe molecule to systematically investigate the photocatalytic reaction on Au MA, and the dependence of the photocatalytic reaction on the particle size of the spheres was discussed. It was found that the smaller size of Au MA has higher catalytic activity. In addition, using conventional gold films as a comparison, no significant photocatalytic reaction was found under the same experimental conditions. The reason is the existence of strong surface plasma "hot spots" in the interstices of the particles on the surface of the Au MA, which promotes the reaction. The above experimental results are of theoretical and practical significance for the in-depth study of the photocatalytic effect of micro-nano array catalytic substrates.

20.
Artículo en Inglés | MEDLINE | ID: mdl-35575696

RESUMEN

Two-dimensional transition-metal dichalcogenides (TMDs) such as monolayer MoS2 exhibit remarkable optical properties. However, the intrinsic absorption and emission rates of MoS2 are very low, thus severely hindering its application in electronics and photonics. Combining MoS2 with a plasmonic optical antenna is an alternative solution to enhance the emission rates of the 2D semiconductor, and this can drastically increase the photoresponsivity of the corresponding photodetector. Herein, we have constructed a plasmonic gap cavity of a nanowire dimer (NWD) system as an optical antenna to brighten the emission of MoS2 off the hot spot. Different from the conventional enhancement concept which occurred in the plasmonic hot spot, the light emission off the nanogap hot spot was thoroughly investigated. We demonstrate that this new plasmonic optical nanostructure leads to a strong enhancement due to the Purcell effect. The NWD optical antenna can trap light to the near field through a high-efficiency plasmonic gap mode (PGM); then the PL emission was enhanced drastically up to 14.5-fold due to the resonance of the plasmonic gap mode (PGM) in the NWD with the excitonic band of monolayer MoS2. Theoretical simulations reveal that this NWD can alter the efficiency of convergence and excitation, which was consistent with our experimental results. This study can provide a pathway toward enhancing and controlling PGM-enhanced light emission of TMD materials beyond the plasmonic hot spot.

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