Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 133
Filtrar
1.
Prev Med Rep ; 42: 102741, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38721570

RESUMO

Background: The purpose of this study was to examine the relationship between sleep duration and risk of sarcopenia in in general U.S. population. Methods: Utilizing publicly available data from the National Health and Nutrition Examination Survey spanning from 2011 to 2014, we explored the association between sleep duration and prevalence of sarcopenia. To investigate their relationship, we conducted weighted multivariate logistic regression analysis, restricted cubic splines (RCS) curve, and subgroup analysis. Results: The study included 8,200 individuals, among whom 99 (0.9 %) had sarcopenia. The RCS curve revealed a U-shaped association of sarcopenia with sleep duration (P for nonlinearity = 0.020), showing that the risk of sarcopenia decreases with increasing sleep duration, reaching the lowest risk around 6.67 h. After controlling for underlying cofounders, compared to individuals with sleep duration < 5 h, the odds ratios with 95 % confidence intervals of sarcopenia were 0.64 (0.27, 1.49), 0.50 (0.20, 1.26), 0.65 (0.27, 1.60), and 2.31 (0.73, 7.30) for < 5-6, 6.5-7.5, 8-9, and > 9 h group. The U-shaped association between sleep time and prevalence of sarcopenia also was observed in the subjects who aged < 40 or ≥ 40 years, were male or female, with or without hypertension, and diabetes mellitus. Conclusions: In summary, both short and long sleep durations increased prevalence of sarcopenia. Further studies are needed to explore the underlying mechanisms.

2.
Angew Chem Int Ed Engl ; : e202404568, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38696242

RESUMO

Few-atom metal clusters (FAMCs) exhibit superior performance in catalyzing complex molecular transformations due to their special spatial environments and electronic states, compared to single-atom catalysts (SACs). However, achieving the efficient and accurate synthesis of FAMCs while avoiding the formation of other species, such as nanoparticles and SACs, still remains challenges. Herein, we report a two-step strategy for synthesis of few-atom platinum (Pt) clusters by predeposition of zinc single-atom-glue (Zn1) on MgO nanosheets (Ptn-Zn1/MgO), where FAMCs can be obtained over a wide range of Pt contents (0.09 to 1.45 wt%). Zn atoms can act as Lewis acidic sites to allow electron transfer between Zn and Pt through bridging O atoms, which play a crucial role in the formation and stabilization of few-atom Pt clusters. Ptn-Zn1/MgO exhibited a high selectivity of 93% for anti-Markovnikov alkene hydrosilylation. Moreover, an excellent activity with a turnover frequency of up to 1.6 ×104 h-1 can be achieved, exceeding most of the reported Pt SACs. Further theoretical studies revealed that the Pt atoms in Ptn-Zn1/MgO possess moderate steric hindrance, which enables high selectivity and activity for hydrosilylation. This work presents some guidelines for utilizing atomic-scale species to increase the synthesis efficiency and precision of FAMCs.

3.
ACS Omega ; 9(8): 9728-9734, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38434882

RESUMO

The distribution of gas and water in the tight gas reservoirs is complex. This limits exploration and development compared to conventional resources. Elucidating the characteristics that control fluid distribution is critical to unlocking the tight gas potential. This study combines geologic analysis with production data to reveal the water chemistry, gas-water distribution, and factors controlling zoning in the study area. The results show that (a) extracted water includes formation brines, condensate, and residual drilling fluids; (b) formation water dominates production, and the salinity of Lower Paleozoic brines is as high as 169,689 mg/L; (c) low NaCl and high metamorphic coefficients indicate that the water bodies are disconnected and the hydrocarbons are well-preserved in several gas-water systems; and (d) paleomorphological features, tectonics, and lithologies control the distribution of gas water. Discrete water bodies are widely distributed.

4.
iScience ; 27(2): 109008, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38352228

RESUMO

Disruption of circadian rhythms during fetal development may predispose mice to developing heart disease later in life. Here, we report that male, but not female, mice that had experienced chronic circadian disturbance (CCD) in utero were more susceptible to pathological cardiac remodeling compared with mice that had developed under normal intrauterine conditions. CCD-treated males showed ventricular chamber dilatation, enhanced myocardial fibrosis, decreased contractility, higher rates of induced tachyarrhythmia, and elevated expression of biomarkers for heart failure and myocardial remodeling. In utero CCD exposure also triggered sex-dependent changes in cardiac gene expression, including upregulation of the secretoglobin gene, Scgb1a1, in males. Importantly, cardiac overexpression of Scgb1a1 was sufficient to induce myocardial hypertrophy in otherwise naive male mice. Our findings reveal that in utero CCD exposure predisposes male mice to pathological remodeling of the heart later in life, likely as a consequence of SCGB1A1 upregulation.

5.
Sci Total Environ ; 913: 169720, 2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38171457

RESUMO

Over the past decades, considerable efforts have been made to find useful solutions for phosphate pollution control. The state transition of nanomaterials from freely dispersed to encapsulated provides a realizable route for their application in phosphate elimination. The separation convenience offered by encapsulation has been widely recognized, however, the unique binding mode of nanostructures and phosphate in the confined space remains unclear, limiting its further development. Here, carboxymethyl cellulose (CMC) microspheres were used as hosts to deploy layered double hydroxide (LDH) nanoparticles. On this basis, we described an attempt to explore the adsorption behavior of LDH and phosphate in the microsphere space. Compared to their freely dispersed analogues, LDH particles exhibited higher structural stability, wider pH adaptability, and better phosphate selectivity when spatially confined in the CMC microsphere. Nevertheless, the kinetic process was severely inhibited by three orders of magnitude. Besides, the saturated phosphate adsorption capacity was also reduced to 74.6 % of the freely dispersed system. A combinative characterization revealed that the highly electronegative CMC host not only causes electrostatic repulsion to phosphate, but also extracts the electron density of the metal center of LDH, weakening its ability to act as a Lewis acid site for phosphate binding. Meanwhile, the microsphere encapsulation also hinders the ion exchange function of interlayer anions and phosphate. This study offers an objective insight into the reaction of LDH and phosphate in the confined microsphere space, which may contribute to the advanced design of encapsulation strategies for nanoparticles.

6.
Microbiol Res ; 280: 127590, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38142517

RESUMO

The detrimental impact of soil salinization on crop productivity and agricultural economy has garnered significant attention. A rhizosphere bacterium with favorable salt tolerance and plant growth-promoting (PGP) functions was isolated in this work. The bacterium was identified as Enterobacter through 16 S rDNA sequencing analysis and designated as Enterobacter sp. JIV1. Interestingly, the presence of putrescine (Put), which had been shown to contribute in reducing abiotic stress damage to plants, significantly promoted strain JIV1 to generate 1-aminocyclopropane-1-carboxylic (ACC) deaminase, dissolve phosphorus and secrete indole-3-acetic acid (IAA). However, the synergy of plant growth promoting rhizobacteria (PGPR) and Put in improving plant salt resistance has not been extensively studied. In this study, strain JIV1 and exogenous Put effectively mitigated the inhibitory impact of salt stress simulated by 200 mM NaCl on rice (Oryza sativa L.) growth. The chlorophyll accumulation, photosynthetic efficiency and antioxidant capacity of rice were also significantly strengthened. Notably, the combined application of strain JIV1 and Put outperformed individual treatments. Moreover, the co-addition of strain JIV1 and Put increased soil protease and urease activities by 451.97% and 51.70% compared to that of salt treatment group. In general, Put-assisted PGPR JIV1 provides a new perspective on alleviating the salt-induced negative impacts on plants.


Assuntos
Enterobacter , Oryza , Solo , Oryza/microbiologia , Putrescina , Estresse Salino , Oxirredução
7.
Proc Natl Acad Sci U S A ; 120(52): e2310916120, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38117856

RESUMO

The kinetics and pathway of most catalyzed reactions depend on the existence of interface, which makes the precise construction of highly active single-atom sites at the reaction interface a desirable goal. Herein, we propose a thermal printing strategy that not only arranges metal atoms at the silica and carbon layer interface but also stabilizes them by strong coordination. Just like the typesetting of Chinese characters on paper, this method relies on the controlled migration of movable nanoparticles between two contact substrates and the simultaneous emission of atoms from the nanoparticle surface at high temperatures. Observed by in situ transmission electron microscopy, a single Fe3O4 nanoparticle migrates from the core of a SiO2 sphere to the surface like a droplet at high temperatures, moves along the interface of SiO2 and the coated carbon layer, and releases metal atoms until it disappears completely. These detached atoms are then in situ trapped by nitrogen and sulfur defects in the carbon layer to generate Fe single-atom sites, exhibiting excellent activity for oxygen reduction reaction. Also, sites' densities can be regulated by controlling the size of Fe3O4 nanoparticle between the two surfaces. More importantly, this strategy is applicable to synthesize Mn, Co, Pt, Pd, Au single-atom sites, which provide a general route to arrange single-atom sites at the interface of different supports for various applications.

8.
Inorg Chem ; 62(46): 19123-19134, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37945002

RESUMO

Electrochemical hydrogeneration (ECH) of biomass-derived platform molecules, which avoids the disadvantages in utilizing fossil fuel and gaseous hydrogen, is a promising route toward value-added chemicals production. Herein, we reported a CoO/Co heterostructure-supported Pt single atoms electrocatalyst (Pt1-CoO/Co) that exhibited an outstanding performance with a high conversion (>99%), a high Faradaic efficiency (87.6%), and robust stability (24 recyclability) at -20 mA/cm2 for electrochemical phenol hydrogenation to high-valued KA oil (a mixture of cyclohexanol and cyclohexanone). Experimental results and the density functional theory calculations demonstrated that Pt1-CoO/Co presented strong adsorption of phenol and hydrogen on the catalyst surface simultaneously, which was conducive to the transfer of the adsorbed hydrogen generated on the single atom Pt sites to activated phenol, and then, ECH of phenol with high performance was achieved instead of the direct hydrogen evolution reaction. This work described that the multicomponent synergistic single atom catalysts could effectively accelerate the ECH of phenol, which could help the achievement of large-scale biomass upgrading.

9.
J Environ Manage ; 348: 119408, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37879180

RESUMO

Sulfamethoxazole (SMX) has been widely detected in various environments and its potential environmental risks have caused great concerns. However, the impact mechanism of SMX on microbial interactions among anammox consortia remain unknown. A long-term exposure experiments (140 d) was carried out to systematically examine the influence of SMX (0-1000 µg/L) on the anammox system, especially microbial network dynamics and variations of key metabolic genes. Results showed that anammox system could adapt to SMX below 500 µg/L and maintain a high nitrogen removal efficiency (NRE) of 85.35 ± 2.42%, while 1000 µg/L SMX significantly decreased the abundance of functional microbes and deteriorated denitrification performance with NRE dropped to 36.92 ± 15.01%. Co-occurrence network analysis indicated that 1000 µg/L SMX decreased the interactions between Proteobacteria and Chloroflexi and limited AnAOB from playing an important role as central nodes in the subnetwork of Planctomycetes. Metagenomics analysis found that genes associated with nitrogen removal (i.e., hdh, hzs, nirS, and hao) showed lower expression level after addition of SMX, while SMX-related ARGs (sul1 and sul2) increased by 1.22 and 2.68 times. This study provided us a relatively comprehensive perspective in response of microbial interactions and metabolic activity to various SMX concentrations.


Assuntos
Oxidação Anaeróbia da Amônia , Sulfametoxazol , Sulfametoxazol/farmacologia , Nitrogênio , Interações Microbianas
10.
Nat Commun ; 14(1): 5338, 2023 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-37660124

RESUMO

Cells possess isolated compartments that spatially confine different enzymes, enabling high-efficiency enzymatic cascade reactions. Herein, we report a cell-inspired design of biomimetic cascade catalysis system by immobilizing Fe single atoms and Au nanoparticles on the inner and outer layers of three-dimensional nanocapsules, respectively. The different metal sites catalyze independently and work synergistically to enable engineered and cascade glucose detection. The biomimetic catalysis system demonstrates ~ 9.8- and 2-fold cascade activity enhancement than conventional mixing and coplanar construction systems, respectively. Furthermore, the biomimetic catalysis system is successfully demonstrated for the colorimetric glucose detection with high catalytic activity and selectivity. Also, the proposed gel-based sensor is integrated with smartphone to enable real-time and visual determination of glucose. More importantly, the gel-based sensor exhibits a high correlation with a commercial glucometer in real samples detection. These findings provide a strategy to design an efficient biomimetic catalysis system for applications in bioassays and nanobiomedicines.


Assuntos
Ouro , Nanopartículas Metálicas , Domínio Catalítico , Catálise , Glucose
11.
Toxics ; 11(7)2023 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-37505600

RESUMO

Due to rapidly expanding crayfish consumption worldwide, the food safety of red swamp crayfish (Procambarus clarkii) is of great concern. China is the largest consumer and producer of crayfish globally. As of yet, it is unknown whether the main crayfish production cities in China are within safe levels of toxic heavy metals and metalloids. For 16 consecutive years, Qianjiang city ranked first in China in processing export volumes of red swamp crayfish. This study presents a comprehensive analysis of the enrichment levels and associated health risks of the species in Qianjiang. In our research, samples of four crayfish tissues, including the head, hepatopancreas, gills, and muscles, were collected from 38 sampling sites distributed in Qianjiang to evaluate the concentration levels of five heavy metals (Pb, Hg, Cd, As, and Cu). The concentration levels of all five metals in muscle did not surpass the national standard. Furthermore, eight significant correlations have been found. For further in-depth assess risk of crayfish in Qianjiang, estimated daily intake (EDI), target hazard quotient (THQ), carcinogenic risk (CR), and estimated maximum allowable consumption rates (CRmm) were evaluated in the abdomen muscle and hepatopancreas. The THQ values for each metal were found to be less than 1, while the CR values were below 10-6. Additionally, the CRmm for adults was determined to be 17.2 meals per month. These findings, based on the analysis of five metallic elements included in this study, suggest that the consumption of crayfish abdomen muscle in Qianjiang does not pose any significant health risks. However, it is noteworthy that certain regions exhibit elevated levels of arsenic in the hepatopancreas, surpassing the national standard, thereby rendering them unsuitable for excessive consumption. In general, the findings can be used to provide guidance for safe dietary practices in China.

12.
Small ; 19(45): e2302328, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37431211

RESUMO

The design of an efficient catalytic system with low Pt loading and excellent stability for the acidic oxygen reduction reaction is still a challenge for the extensive application of proton-exchange membrane fuel cells. Here, a gas-phase ordered alloying strategy is proposed to construct an effective synergistic catalytic system that blends PtM intermetallic compounds (PtM IMC, M = Fe, Cu, and Ni) and dense isolated transition metal sites (M-N4 ) on nitrogen-doped carbon (NC). This strategy enables Pt nanoparticles and defects on the NC support to timely trap flowing metal salt without partial aggregation, which is attributed to the good diffusivity of gaseous transition metal salts with low boiling points. In particular, the resulting Pt1 Fe1 IMC cooperating with Fe-N4 sites achieves cooperative oxygen reduction with a half-wave potential up to 0.94 V and leads to a high mass activity of 0.51 A  mgPt -1 and only 23.5% decay after 30 k cycles, both of which exceed DOE 2025 targets. This strategy provides a method for reducing Pt loading in fuel cells by integrating Pt-based intermetallics and single transition metal sites to produce an efficient synergistic catalytic system.

13.
J Am Chem Soc ; 145(24): 13462-13468, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37293805

RESUMO

Arranging atoms in an orderly manner at the atomic scale to create stable polyatomic structures is a very challenging task. In this study, we have developed three-dimensional confinement areas on the two-dimensional surface by creating regional defects. These areas are composed of vertically stacked graphene layers, where Ni and Fe atoms are anchored concentrically to form axial dual atomic sites in high yield. These sites can be used to produce tunable syngas through the electroreduction of CO2. Theoretical calculations indicate that the Ni sites vertically regulate the charge distribution of the adjacent Fe sites in the layer below, resulting in a lower d-band center. This, in turn, weakens the adsorption of the *CO intermediate and inhibits the production of H2 at the Fe site. Our research presents a novel approach for concentrated creation of dual atomic sites by building a confinement-selective surface.

14.
Sci Rep ; 13(1): 7626, 2023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-37165051

RESUMO

Although exogenous glycine betaine (GB) and cycloleucine (Cyc) have been reported to affect animal cell metabolism, their effects on plant growth and development have not been studied extensively. Different concentrations of exogenous glycine betaine (20, 40, and 60 mmol L-1) and cycloleucine (10, 20, and 40 mmol L-1), with 0 mmol L-1 as control, were used to investigate the effects of foliar spraying of betaine and cycloleucine on growth, photosynthesis, chlorophyll fluorescence, Calvin cycle pathway, abaxial leaf burr morphology, endogenous hormones, and amino acid content in eggplant. We found that 40 mmol L-1 glycine betaine had the best effect on plant growth and development; it increased the fresh and dry weight of plants, increased the density of abaxial leaf hairs, increased the net photosynthetic rate and Calvin cycle key enzyme activity of leaves, had an elevating effect on chlorophyll fluorescence parameters, increased endogenous indoleacetic acid (IAA) content and decreased abscisic acid (ABA) content, and increased glutamate, serine, aspartate, and phenylalanine contents. However, cycloleucine significantly inhibited plant growth; plant apical dominance disappeared, plant height and dry and fresh weights decreased significantly, the development of abaxial leaf hairs was hindered, the net photosynthetic rate and Calvin cycle key enzyme activities were inhibited, the endogenous hormones IAA and ABA content decreased, and the conversion and utilization of glutamate, arginine, threonine, and glycine were affected. Combined with the experimental results and plant growth phenotypes, 20 mmol L-1 cycloleucine significantly inhibited plant growth. In conclusion, 40 mmol L-1 glycine betaine and 20 mmol L-1 cycloleucine had different regulatory effects on plant growth and development.


Assuntos
Betaína , Solanum melongena , Betaína/farmacologia , Betaína/metabolismo , Solanum melongena/metabolismo , Cicloleucina/metabolismo , Cicloleucina/farmacologia , Aminoácidos/metabolismo , Fotossíntese , Ácido Abscísico/metabolismo , Clorofila/metabolismo , Hormônios/metabolismo , Folhas de Planta/metabolismo
15.
Infect Immun ; 91(5): e0002923, 2023 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-37039643

RESUMO

Cystic echinococcosis (CE) is a common zoonotic parasitic disease that seriously impacts public health. However, the full spectrum of immune cell changes in Echinococcus granulosus infection, especially the negative immune regulation of subpopulations of regulatory T (Treg) cells, are not yet well understood. In this study, we used single-cell RNA sequencing and immunome repertoire (IR) sequencing to analyze 53,298 cells from the spleens and peripheral blood mononuclear cells (PBMCs) of healthy and E. granulosus-infected mice. We used immunofluorescence combined with RNA fluorescence in situ hybridization and quantitative real-time PCR to verify the sequencing results. Our results showed tissue-specific immune system alterations in mice infected with E. granulosus. E. granulosus-infected mice induced a subpopulation of CD4+ cells with type I interferon production potential. Furthermore, there were six different Treg cell subpopulations in vivo at three stages of differentiation, and Treg subpopulations of different classes and different stages of differentiation showed tissue specificity. After infection, the Lag3hi Treg and Gpr83+Igfbp4+ naive Treg subpopulations were specifically induced in PBMCs and the spleen, respectively. Furthermore, T follicular helper 2 (Tfh2) cells with high expression of Cxxc5 and Spock2 were found in E. granulosus-infected mice. Our data uncovered changes in the full spectrum of immune cells in mice following the late stages of E. granulosus infection, including subpopulations of cells that have not been emphasized in previous studies. These results further enrich the study of the bidirectional immunomodulatory mechanism and offer a different perspective for subsequent studies of infection in E. granulosus.


Assuntos
Equinococose , Echinococcus granulosus , Animais , Camundongos , Echinococcus granulosus/genética , Linfócitos T Reguladores , Hibridização in Situ Fluorescente , Leucócitos Mononucleares , Zoonoses , Análise de Sequência de RNA , Receptores Acoplados a Proteínas G , Proteínas de Ligação a DNA , Fatores de Transcrição
16.
Biomed Pharmacother ; 162: 114702, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37062221

RESUMO

BACKGROUND: Vaccination is the most effective way to prevent coronavirus disease 2019 (COVID-19). However, it is often less protective and does not significantly increase antibody levels, especially in individuals with impaired immune systems. Nevertheless, the immunocompetence can be enhanced using a natural immunomodulator, such as Dendrobium officinale aqueous extract (DoAE). METHODS: To determine whether DoAE promotes antibody production, we treated healthy volunteers with DoAE during COVID-19 vaccination. Meanwhile, the control volunteers were given a placebo (cornstarch) during the vaccination. Antibody levels were measured at three-week intervals in the DoAE and control groups. RESULTS: DoAE enhanced immunity and preserved immune cell homeostasis. However, the neutralizing antibody (nAb) levels in the DoAE group were lower than those in the control group. Analysis of the gut microbiota revealed that the abundance of anti-inflammatory flora was increased, while the pro-inflammatory flora was reduced in the DoAE group. CONCLUSION: DoAE has immunomodulatory and anti-inflammatory properties. Therefore, DoAE has the potential for COVID-19 prophylaxis, treatment, and recovery from the adverse effects of COVID-19. However, its anti-inflammatory activity affects the production of nAbs. Thus, DoAE may not be recommended for consumption during COVID-19 vaccination.


Assuntos
COVID-19 , Dendrobium , Humanos , Adjuvantes Imunológicos , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacinas contra COVID-19 , SARS-CoV-2 , Vacinação
17.
Front Microbiol ; 14: 1105723, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36876107

RESUMO

Soil microorganisms are critical biological indicators for evaluating soil health and play a vital role in carbon (C)-climate feedback. In recent years, the accuracy of models in terms of predicting soil C pools has been improved by considering the involvement of microbes in the decomposition process in ecosystem models, but the parameter values of these models have been assumed by researchers without combining observed data with the models and without calibrating the microbial decomposition models. Here, we conducted an observational experiment from April 2021 to July 2022 in the Ziwuling Mountains, Loess Plateau, China, to explore the main influencing factors of soil respiration (RS) and determine which parameters can be incorporated into microbial decomposition models. The results showed that the RS rate is significantly correlated with soil temperature (TS) and moisture (MS), indicating that TS increases soil C loss. We attributed the non-significant correlation between RS and soil microbial biomass carbon (MBC) to variations in microbial use efficiency, which mitigated ecosystem C loss by reducing the ability of microorganisms to decompose organic resources at high temperatures. The structural equation modeling (SEM) results demonstrated that TS, microbial biomass, and enzyme activity are crucial factors affecting soil microbial activity. Our study revealed the relations between TS, microbial biomass, enzyme activity, and RS, which had important scientific implications for constructing microbial decomposition models that predict soil microbial activity under climate change in the future. To better understand the relationship between soil dynamics and C emissions, it will be necessary to incorporate climate data as well as RS and microbial parameters into microbial decomposition models, which will be important for soil conservation and reducing soil C loss in the Loess Plateau.

18.
Angew Chem Int Ed Engl ; 62(12): e202300879, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36721306

RESUMO

Charge redistribution on surface of Ru nanoparticle can significantly affect electrocatalytic HER activity. Herein, a double atomic-tuned RuBi SAA/Bi@OG nanostructure that features RuBi single-atom alloy nanoparticle supported by Bi-O single-site-doped graphene was successfully developed by one-step pyrolysis method. The alloyed Bi single atom and adjacent Bi-O single site in RuBi SAA/Bi@OG can synergistically manipulate electron transfer on Ru surface leading to optimum charge redistribution. Thus, the resulting RuBi SAA/Bi@OG exhibits superior alkaline HER activity. Its mass activity is up to 65000 mA mg-1 at an overpotential of 150 mV, which is 72.2 times as much as that of commercial Pt/C. DFT calculations reveal that the RuBi SAA/Bi@OG possesses the optimum charge redistribution, which is most beneficial to strengthen adsorption of water and weaken hydrogen-adsorption free energy in HER process. This double atomic-tuned strategy on surface charge redistribution of Ru nanoparticle opens a new way to develop highly efficient electrocatalysts.

19.
J Hazard Mater ; 448: 130821, 2023 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-36709736

RESUMO

Lignin, the most abundant source of renewable aromatic compounds derived from natural lignocellulosic biomass, has great potential for various applications as green materials due to its abundant active groups. However, it is still challenging to quickly construct green polymers with a certain crystallinity by utilizing lignin as a building block. Herein, new green lignin-based covalent organic polymers (LIGOPD-COPs) were one-pot fabricated with water as the reaction solvent and natural lignin as the raw material. Furthermore, by using paraformaldehyde as a protector and modulator, the LIGOPD-COPs prepared under optimized conditions displayed better crystallinity than reported lignin-based polymers, demonstrating the feasibility of preparing lignin-based polymers with improved crystallinity. The improved crystallinity confers LIGOPD-COPs with enhanced application performance, which was demonstrated by their excellent performances in sample treatment of non-targeted food safety analysis. Under optimized conditions, phytochromes, the main interfering matrices, were almost completely removed from different phytochromes-rich vegetables by LIGOPD-COPs, accompanied by "full recovery" of 90 chemical hazards. Green, low-cost, and reusable properties, together with improved crystallinity, will accelerate the industrialization and marketization of lignin-based COPs, and promote their applications in many fields.


Assuntos
Lignina , Polímeros , Lignina/química , Polímeros/química , Biomassa , Água , Solventes
20.
Adv Mater ; 35(5): e2208704, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36411951

RESUMO

Coordination environment and site density have great impacts on the catalytic performance for single atoms (SAs). Herein, the site density of Mo-SAs on red polymeric carbon nitrides (RPCN) is modulated via a local carbonization strategy to controllably catch adventitious O atoms from open environment. The addition of melamine derivants with hydrocarbyl chains induces local carbonization during RPCN pyrolysis. These local carbonization regions bring abundant graphitic N3C to anchor Mo-SAs, and most of Mo-SAs catch the O atoms in air, forming the O2 -covered Mo-N3 coordination. The dopants of carbon source with different structures and amounts can modulate the site density of Mo-SAs, therefore controlling the amounts of coordinated O atoms. Furthermore, coordinated O atoms around Mo-SAs construct the catalytic environment with Lewis base and gather photo-generated electrons under light. Such O-covered Mo-SAs endow RPCN materials (Mo-RPCN) with a strong ability for hydrogen abstraction, leading to the 99.51% ratio (28.8 mmol min-1  g-1 ) rate for thioanisole conversion with H2 O2 assisted advance oxidation technology. This work brings a new sight on the coordinated atoms dominant oxidation process.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...