Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 97
Filtrar
1.
J Phys Chem B ; 128(15): 3732-3741, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38568211

RESUMO

Using nanobubbles as geometrical confinements, we create a thin water film (∼10 nm) in a graphene liquid cell and investigate the evolution of its instability at the nanoscale under transmission electron microscopy. The breakdown of the water films, resulting in the subsequent formation and growth of nanodroplets, is visualized and generalized into different modes. We identified distinct droplet formation and growth modes by analyzing the dynamic processes involving 61 droplets and 110 liquid bridges within 31 Graphene Liquid Cells (GLCs). Droplet formation is influenced by their positions in GLCs, taking on a semicircular shape at the edge and a circular shape in the middle. Growth modes include liquid mass transfer driven by Plateau-Rayleigh instability and merging processes in and out-of-plane of the graphene interface. Droplet growth can lead to the formation of liquid bridges for which we obtain multiview projections. Data analysis reveals the general dynamics of liquid bridges, including drawing liquids from neighboring residual water films, merging with surrounding droplets, and merging with other liquid bridges. Our experimental observations provide insights into fluid transport at the nanoscale.

2.
Angew Chem Int Ed Engl ; : e202403260, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38503695

RESUMO

The poisoning of undesired intermediates or impurities greatly hinders the catalytic performances of noble metal-based catalysts. Herein, high-entropy intermetallics i-(PtPdIrRu)2FeCu (HEI) are constructed to inhibit the strongly adsorbed carbon monoxide intermediates (CO*) during the formic acid oxidation reaction. As probed by multiple-scaled structural characterizations, HEI nanoparticles are featured with partially negative Pt oxidation states, diluted Pt/Pd/Ir/Ru atomic sites and ultrasmall average size less than 2 nm. Benefiting from the optimized structures, HEI nanoparticles deliver more than 10 times promotion in intrinsic activity than that of pure Pt, and well-enhanced mass activity/durability than that of ternary i-Pt2FeCu intermetallics counterpart. In situ infrared spectroscopy manifests that both bridge and top CO* are favored on pure Pt but limited on HEI. Further theoretical elaboration indicates that HEI displayed a much weaker binding of CO* on Pt sites and sluggish diffusion of CO* among different sites, in contrast to pure Pt that CO* bound more strongly and was easy to diffuse on larger Pt atomic ensembles. This work verifies that HEIs are promising catalysts via integrating the merits of intermetallics and high-entropy alloys.

3.
Plant J ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38526880

RESUMO

Rice (Oryza sativa L.) is a short-day plant whose heading date is largely determined by photoperiod sensitivity (PS). Many parental lines used in hybrid rice breeding have weak PS, but their F1 progenies have strong PS and exhibit an undesirable transgressive late-maturing phenotype. However, the genetic basis for this phenomenon is unclear. Therefore, effective methods are needed for selecting parents to create F1 hybrid varieties with the desired PS. In this study, we used bulked segregant analysis with F1 Ningyou 1179 (strong PS) and its F2 population, and through analyzing both parental haplotypes and PS data for 918 hybrid rice varieties, to identify the genetic basis of transgressive late maturation which is dependent on dominance complementation effects of Hd1, Ghd7, DTH8, and PRR37 from both parents rather than from a single parental genotype. We designed a molecular marker-assisted selection system to identify the genotypes of Hd1, Ghd7, DTH8, and PRR37 in parental lines to predict PS in F1 plants prior to crossing. Furthermore, we used CRISPR/Cas9 technique to knock out Hd1 in Ning A (sterile line) and Ning B (maintainer line) and obtained an hd1-NY material with weak PS while retaining the elite agronomic traits of NY. Our findings clarified the genetic basis of transgressive late maturation in hybrid rice and developed effective methods for parental selection and gene editing to facilitate the breeding of hybrid varieties with the desired PS for improving their adaptability.

4.
Environ Toxicol ; 39(3): 1641-1649, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38018869

RESUMO

OBJECTIVE: The present study aimed to elucidate mechanisms of liothyronine on the treatment of ischemic stroke (IS). METHODS: Differential analysis based on R limma package was used to identify differentially expressed genes, which were then mapped into the connectivity map database for identification of liothyronine associated with IS. Tumor necrosis factor (TNF) signaling pathway was verified through pathway enrichment analysis via Enrichr online. Ischemia stroke mouse model was built up for further analysis. Infarct area and regional cerebral blood flow (rCBF) were measured by 2, 3, 5-triphenyltetrazolium chloride and laser Doppler flowmetry, respectively. Light microscope was used for the evaluation of body weight and dark neurons. Serum TXB2 , 6-Keto-PGF1a , TNF-α, and interleukin-6 (IL-6) levels in mice were measured using enzyme-linked immuno sorbent assay. In addition, relative protein expression levels of brain-derived neurotrophic factor, nestin, and Sox2 were detected by Western blot analysis. RESULTS: Liothyronine with a negative connectivity was identified as one promising treatment for IS through TNF signaling pathway. The experimental results showed that liothyronine treatment significantly meliorated infarct area and the number of dark neurons in IS mice. Liothyronine greatly ameliorated the expression levels of TXB2 and 6-Keto-PGF1a . Besides, rCBF and body weight change of IS mice were increased gradually with increase of drug concentration. Based on pathway enrichment analysis, anti-inflammatory response (TNF-α and IL-6) relevant to TNF signaling pathway was identified, which was further validated in vitro. Furthermore, proteins as neural stem cell markers made a difference with liothyronine treatment. CONCLUSION: Liothyronine may be a novel therapeutic component to exploit an effective medicine for the treatment of IS.


Assuntos
AVC Isquêmico , Camundongos , Animais , Tri-Iodotironina , Fator de Necrose Tumoral alfa/genética , Farmacologia em Rede , Interleucina-6 , Infarto , Peso Corporal
5.
Angew Chem Int Ed Engl ; 63(5): e202315148, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38078596

RESUMO

Tracking the trajectory of hydrogen intermediates during hydrogen electro-catalysis is beneficial for designing synergetic multi-component catalysts with division of chemical labor. Herein, we demonstrate a novel dynamic lattice hydrogen (LH) migration mechanism that leads to two orders of magnitude increase in the alkaline hydrogen oxidation reaction (HOR) activity on Pd@Pt over pure Pd, even ≈31.8 times mass activity enhancement than commercial Pt. Specifically, the polarization-driven electrochemical hydrogenation process from Pd@Pt to PdHx @Pt by incorporating LH allows more surface vacancy Pt sites to increase the surface H coverage. The inverse dehydrogenation process makes PdHx as an H reservoir, providing LH migrates to the surface of Pt and participates in the HOR. Meanwhile, the formation of PdHx induces electronic effect, lowering the energy barrier of rate-determining Volmer step, thus resulting in the HOR kinetics on Pd@Pt being proportional to the LH concentration in the in situ formed PdHx @Pt. Moreover, this dynamic catalysis mechanism would open up the catalysts scope for hydrogen electro-catalysis.

6.
J Phys Chem Lett ; 15(1): 34-42, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38127717

RESUMO

The surface electronic structures of catalysts play a crucial role in CO2 adsorption and activation. Here, sulfur vacancies are introduced into CuInS2 nanosheets (Vs-CuInS2) to evaluate the effect of electronic structures at the surface-active sites on the electrochemical CO2 reduction reaction (CO2RR). Vs-CuInS2 exhibits a significant disparity in the highest FEformate/FECO (6.50) compared to that of CuInS2 (1.86). Specifically, the maximum current density (Jmax) of carbon products on Vs-CuInS2 is 78.78 mA cm-2, and a Faraday efficiency of carbon products (FEcarbon products) of ≥80% is achieved in 600 mV wide potential windows. In situ Raman measurements and density functional theory calculations elucidate the origin of the apparent alterations in the carbon product selectivity. The introduction of sulfur vacancies realizes the controllable regulation of the local electronic density around the metal active sites, inducing the transformation of *COOH and *OCHO from competitive adsorption on CuInS2 to specific adsorption on Vs-CuInS2. In addition, the regulation of electronic structures on Vs-CuInS2 inhibits *H adsorption. This work reveals the transfer of adsorption of CO2RR intermediates via regulation of the electronic structure, complementing the understanding of the mechanism for the enhanced CO2RR.

7.
JACS Au ; 3(11): 3127-3140, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38034977

RESUMO

Given the rapid recombination of photogenerated charge carriers and photocorrosion, transition metal sulfide photocatalysts usually suffer from modest photocatalytic performance. Herein, S-vacancy-rich ZnIn2S4 (VS-ZIS) nanosheets are integrated on 3D bicontinuous nitrogen-doped nanoporous graphene (N-npG), forming 3D heterostructures with well-fitted geometric configuration (VS-ZIS/N-npG) for highly efficient photocatalytic hydrogen production. The VS-ZIS/N-npG presents ultrafast interfacial photogenerated electrons captured by the S vacancies in VS-ZIS and holes neutralization behaviors by the extra free electrons in N-npG during photocatalysis, which are demonstrated by in situ XPS, femtosecond transient absorption (fs-TA) spectroscopy, and transient-state surface photovoltage (TS-SPV) spectra. The simulated interfacial charge rearrangement behaviors from DFT calculations also verify the separation tendency of photogenerated charge carriers. Thus, the optimized VS-ZIS/N-npG 3D hierarchical heterojunction with 1.0 wt % N-npG exhibits a comparably high hydrogen generation rate of 4222.4 µmol g-1 h-1, which is 5.6-fold higher than the bare VS-ZIS and 12.7-fold higher than the ZIS without S vacancies. This work sheds light on the rational design of photogenerated carrier transfer paths to facilitate charge separation and provides further hints for the design of hierarchical heterostructure photocatalysts.

8.
Theor Appl Genet ; 136(12): 239, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37930441

RESUMO

KEY MESSAGE: We developed an efficient promoter editing method to create different weak Ehd1 alleles in elite japonica rice variety ZJ8 with slightly delayed heading and improved yield for use in breeding. Heading date is an important agronomic trait of rice (Oryza sativa) that determines the planting areas and cultivation seasons of different varieties, thus affecting final yield. Early heading date 1 (Ehd1) is a major rice integrator gene in the regulatory network of heading date whose expression level is negatively correlated with heading date and grain yield. Some elite japonica varieties such as Zhongjia 8 (ZJ8) show very early heading with poor agronomic traits when planted in South China. This problem can be addressed by downregulating the expression of Ehd1. In this study, we analyzed the cis-regulatory elements in the Ehd1 promoter region. We then used CRISPR/Cas9-mediated editing to modify the Ehd1 promoter at multiple target sites in ZJ8. We rapidly identified homozygous allelic mutations in the T2 generation via long-read sequencing. We obtained several Ehd1 promoter mutants with different degrees of lower Ehd1 expression, delayed heading date, and improved yield-related traits. We developed an efficient promoter editing method to create different weak Ehd1 alleles for breeding selection. Using this method, a series of heading date materials from elite varieties can be created to expand the planting area of rice and improve grain yields.


Assuntos
Oryza , Oryza/genética , Melhoramento Vegetal , Regiões Promotoras Genéticas , Agricultura , Alelos , Grão Comestível/genética
9.
Natl Sci Rev ; 10(12): nwad079, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37954203

RESUMO

Lunar glasses with different origins act as snapshots of their formation processes, providing a rich archive of the Moon's formation and evolution. Here, we reveal diverse glasses from Chang'E-5 (CE-5) lunar regolith, and clarify their physical origins of liquid quenching, vapor deposition and irradiation damage respectively. The series of quenched glasses, including rotation-featured particles, vesicular agglutinates and adhered melts, record multiple-scale impact events. Abundant micro-impact products, like micron- to nano-scale glass droplets or craters, highlight that the regolith is heavily reworked by frequent micrometeorite bombardment. Distinct from Apollo samples, the indigenous ultra-elongated glass fibers drawn from viscous melts and the widespread ultra-thin deposited amorphous rims without nanophase iron particles both indicate a relatively gentle impact environment at the CE-5 landing site. The clarification of multitype CE-5 glasses also provides a catalogue of diverse lunar glasses, meaning that more of the Moon's mysteries, recorded in glasses, could be deciphered in future.

10.
Lasers Med Sci ; 38(1): 279, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-38030741

RESUMO

The study aimed to investigate the clinical effect of transurethral columnar balloon dilation of the prostate combined with holmium laser in the treatment of bladder neck contracture (BNC). This retrospective study included 41 patients with BNC, who had been treated with transurethral columnar balloon dilation and holmium laser in our hospital from June 2020 to June 2022. Admission, operation, and discharge of all the patients were completed in 24 h. The patients' satisfaction, postoperative complications, and chronic pain after operation were followed up. Clinical parameters, such as International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), quality of life (QoL), and post-void residual volume (PVR) in pre-operation, 1 month and 6 months after operation were recorded. All patients underwent the operations successfully. Six patients experienced urge incontinence and one patient experienced recurrence of BNC after 12 months. At 1 month and 6 months after the operation, IPSS, QoL, PVR, and Qmax of the patients were significantly better than those before the operation (P < 0.05). Transurethral columnar balloon dilation of the prostate combined with holmium laser can effectively treat BNC with simple performance and satisfactory clinical effects. It is a minimally invasive treatment that can be conducted by simple day surgery.


Assuntos
Contratura , Terapia a Laser , Lasers de Estado Sólido , Hiperplasia Prostática , Ressecção Transuretral da Próstata , Masculino , Humanos , Próstata/cirurgia , Bexiga Urinária/cirurgia , Lasers de Estado Sólido/uso terapêutico , Qualidade de Vida , Procedimentos Cirúrgicos Ambulatórios , Estudos Retrospectivos , Dilatação , Hiperplasia Prostática/cirurgia , Hiperplasia Prostática/complicações , Contratura/cirurgia , Contratura/complicações , Resultado do Tratamento
11.
Theor Appl Genet ; 136(11): 227, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37851149

RESUMO

KEY MESSAGE: We clarify the influence of the genotypes of the heading date genes Hd1, Ghd7, DTH8, and PRR37 and their combinations on yield-related traits and the functional differences between different haplotypes. Heading date is a key agronomic trait in rice (Oryza sativa L.) that determines yield and adaptability to different latitudes. Heading date 1 (Hd1), Grain number, plant height, and heading date 7 (Ghd7), Days to heading on chromosome 8 (DTH8), and PSEUDO-RESPONSE REGULATOR 37 (PRR37) are core rice genes controlling photoperiod sensitivity, and these genes have many haplotypes in rice cultivars. However, the effects of different haplotypes at these genes on yield-related traits in diverse rice materials remain poorly characterized. In this study, we knocked out Hd1, Ghd7, DTH8, or PRR37, alone or together, in indica and japonica varieties and systematically investigated the agronomic traits of each knockout line. Ghd7 and PRR37 increased the number of spikelets and improved yield, and this effect was enhanced with the Ghd7 DTH8 or Ghd7 PRR37 combination, but Hd1 negatively affected yield. We also identified a new weak functional Ghd7 allele containing a mutation that interferes with splicing. Furthermore, we determined that the promotion or inhibition of heading date by different PRR37 haplotypes is related to PRR37 expression levels, day length, and the genetic background. For rice breeding, a combination of functional alleles of Ghd7 and DTH8 or Ghd7 and PRR37 in the hd1 background can be used to increase yield. Our study clarifies the effects of heading date genes on yield-related traits and the functional differences among their different haplotypes, providing valuable information to identify and exploit elite haplotypes for heading date genes to breed high-yielding rice varieties.


Assuntos
Oryza , Oryza/metabolismo , Melhoramento Vegetal , Fenótipo , Mutação , Genótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas , Flores/genética , Fotoperíodo
12.
Eur Radiol ; 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37812296

RESUMO

OBJECTIVE: The purpose of this study was to develop and validate a nomogram combined multiparametric MRI and clinical indicators for identifying the WHO grade of meningioma. MATERIALS AND METHODS: Five hundred and sixty-eight patients were included in this study, who were diagnosed pathologically as having meningiomas. Firstly, radiomics features were extracted from CE-T1, T2, and 1-cm-thick tumor-to-brain interface (BTI) images. Then, difference analysis and the least absolute shrinkage and selection operator were orderly used to select the most representative features. Next, the support vector machine algorithm was conducted to predict the WHO grade of meningioma. Furthermore, a nomogram incorporated radiomics features and valuable clinical indicators was constructed by logistic regression. The performance of the nomogram was assessed by calibration and clinical effectiveness, as well as internal validation. RESULTS: Peritumoral edema volume and gender are independent risk factors for predicting meningioma grade. The multiparametric MRI features incorporating CE-T1, T2, and BTI features showed the higher performance for prediction of meningioma grade with a pooled AUC = 0.885 (95% CI, 0.821-0.946) and 0.860 (95% CI, 0.788-0.923) in the training and test groups, respectively. Then, a nomogram with a pooled AUC = 0.912 (95% CI, 0.876-0.961), combined radiomics score, peritumoral edema volume, and gender improved diagnostic performance compared to radiomics model or clinical model and showed good calibration as the true results. Moreover, decision curve analysis demonstrated satisfactory clinical effectiveness of the proposed nomogram. CONCLUSIONS: A novel nomogram is simple yet effective in differentiating WHO grades of meningioma and thus can be used in patients with meningiomas. CLINICAL RELEVANCE STATEMENT: We proposed a nomogram that included clinical indicators and multi-parameter radiomics features, which can accurately, objectively, and non-invasively differentiate WHO grading of meningioma and thus can be used in clinical work. KEY POINTS: • The study combined radiomics features and clinical indicators for objectively predicting the meningioma grade. • The model with CE-T1 + T2 + brain-to-tumor interface features demonstrated the best predictive performance by investigating seven different radiomics models. • The nomogram potentially has clinical applications in distinguishing high-grade and low-grade meningiomas.

13.
BMC Infect Dis ; 23(1): 589, 2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37679704

RESUMO

BACKGROUND: During endotracheal intubation, extubation, tracheotomy, and tracheotomy tube replacement, the splashed airway secretions of patients will increase the risk of transmission of SARS-CoV-2 and many other potential viral and bacterial diseases, such as influenza virus, adenovirus, respiratory syncytial virus, rhinovirus, Middle East respiratory coronavirus syndrome (MERS-CoV), Streptococcus pneumoniae, and Mycobacterium tuberculosis. Therefore, it is necessary to establish a barrier between patients and medical workers to reduce the risk of operators' infection with potentially pathogenic microorganisms. METHODS: We designed a "safety cap" that can be connected to the opening of an endotracheal tube or tracheotomy tube to reduce the diffusion area of respiratory secretions during the process of endotracheal intubation, extubation and tracheotomy tube replace, so as to reduce the infection risk of medical workers. RESULTS: Through a series of hydrodynamic simulation analysis and experiments, we demonstrated that the use of "safety cap" can substantially limit the spatter of airway secretions, so as to improve the hospital sanitation. CONCLUSION: The "safety cap" can effectively limit the dissemination of patients' respiratory secretions, thus reducing the risk of potential diseases transmission and may have certain application prospects.


Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , SARS-CoV-2 , Saneamento , Intubação Intratraqueal , Hospitais
14.
Front Psychiatry ; 14: 1178834, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37575569

RESUMO

Objective: The prevalence of mental distress has been noted in shelter hospitals set up for COVID-19. Potential risk demographic and hospitalization factors were screened. We also aimed to determine whether humanistic care established in the shelter hospital was effective in ameliorating mental distress. Methods: A cross-sectional observational survey-based single-centered study was conducted from 28th April to 5th May 2022 during the COVID-19 pandemic in Shanghai. Asymptomatic adult inpatients and those with mild symptoms were recruited for this study, and humanistic care measures were carried out by the administrative office according to the Work Program on Psychological Assistance and Social Work Services at the Shelter Hospital launched on 5th March 2020. Symptoms of mental distress, such as reported stress, anxiety, depression, and insomnia were measured using the Chinese Stress Response Questionnaire-28, the Chinese version of Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, and Insomnia Severity Index-7, respectively. Results: In total, 1,246 out of 9,519 inpatients, including 565 (45.35%) women and 681 (54.65%) men, with a median age of 36 years responded to the survey. The overall prevalence of stress, anxiety, depression, and insomnia in inpatients was 94 (7.54%), 109 (8.75%), 141 (11.32%), and 144 (11.56%), respectively. Mental distress was aggravated by COVID-19-related symptoms, comorbidities, and prolonged hospital stays. A stable internet connection was the most effective measure to reduce stress and depression. Offering inpatient with study or work facilitations, and mental health education help to ameliorate anxiety and depression. Organizing volunteering was a potential protective factor against stress. Conclusion: Humanistic care is crucial and effective for protecting against mental distress, which should be emphasized in shelter hospitals.

15.
World J Urol ; 41(8): 2249-2253, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37391668

RESUMO

INTRODUCTION: Our study aimed to describe the outcomes of transurethral enucleation of the prostate (HoLEP) for large-sized benign prostatic hyperplasia over 150 mL (bBPH). METHODS: We conducted a retrospective, descriptive, and analytical study of patients undergoing HoLEP for bBPH. The primary endpoint was the success of the procedure, defined by a mixed criteria: complete endoscopic enucleation of the prostate, absence of blood transfusion or reoperation for bleeding, post-operative improvement of quality of life (assessed by a ≥ 2 points increase at in the 8th question of the IPSS test) and post-operative continence (no pads use) at 3 months. RESULTS: Eighty-one patients were included with a mean age of 73.9 ± 7.3 and a mean measured prostate volume of 183.3 ± 34.5 cc. The mean operative time was 57.5 ± 29.7 min and the average wet weight of resected tissue removed was 151.8 ± 44.7 g. Mean hospitalization stay was 1.3 ± 0.7 days with a mean post-operative catheterization period of 1.9 ± 0.9 days. The success of the surgery was achieved in 77 patients (95%). Functional improvements were found at 1 and 6 months for Qmax, post-void residual, IPSS and QoL-IPSS. The 30-day complication rate was 9.9%. The average PSA level dropped from 14.8 ± 11.6 ng/mL at baseline to 0.8 ± 0.5 ng/mL at 6 months. CONCLUSION: HoLEP for bBPH is both safe and efficient. Regarding the benefit/risk balance, it should be highlighted as the gold standard for the management of big BPH.


Assuntos
Terapia a Laser , Lasers de Estado Sólido , Hiperplasia Prostática , Masculino , Humanos , Idoso , Idoso de 80 Anos ou mais , Próstata/cirurgia , Hiperplasia Prostática/cirurgia , Hiperplasia Prostática/complicações , Qualidade de Vida , Lasers de Estado Sólido/uso terapêutico , Estudos Retrospectivos , Prostatectomia/métodos , Terapia a Laser/métodos , Hólmio , Resultado do Tratamento
16.
Small ; 19(37): e2301738, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37140103

RESUMO

A drawback with lithium-ion batteries (LIBs) lies in the unstable lithium storage which results in poor electrochemical performance. Therefore, it's of importance to improve the electrochemical functionality and Li-ion transport kinetics of electrode materials for high-performance lithium storage. Here, a subtle atom engineering via injecting molybdenum (Mo) atoms into vanadium disulfide (VS2 ) to boost high capacity Li-ion storage is reported. By combining operando, ex situ monitoring and theoretical simulation, it is confirmed that the 5.0%Mo atoms impart flower-like VS2 with expanded interplanar spacing, lowered Li-ion diffusion energy barrier, and increased Li-ion adsorption property, together with enhanced e- conductivity, to boost Li-ion migration. A "speculatively" optimized 5.0% Mo-VS2 cathode that exhibits a specific capacity of 260.8 mA h g-1 at 1.0 A g-1 together with a low decay of 0.009% per cycle over 500 cycles is demonstrated. It is shown that this value is ≈1.5 times compared with that for bare VS2 cathode. This investigation has substantiated the Mo atom doping can effectively guide the Li-ion storage and open new frontiers for exploiting high-performance transition metal dichalcogenides for LIBs.

18.
Angew Chem Int Ed Engl ; 62(22): e202302170, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37002861

RESUMO

Layered transition metal oxide cathodes have been one of the dominant cathodes for lithium-ion batteries with efficient Li+ intercalation chemistry. However, limited by the weak layered interaction and unstable surface, mechanical and chemical failure plagues their electrochemical performance, especially for Ni-rich cathodes. Here, adopting a simultaneous elemental-structural atomic arrangement control based on the intrinsic Ni-Co-Mn system, the surface role is intensively investigated. Within the invariant oxygen sublattice of the crystal, a robust surface with the synergistic concentration gradient and layered-spinel intertwined structure is constructed on the model single-crystalline Ni-rich cathode. With mechanical strain dissipation and chemical erosion suppression, the cathode exhibits an impressive capacity retention of 82 % even at the harsh 60 °C after 150 cycles at 1 C. This work highlights the coupling effect of structure and composition on the chemical-mechanical properties, and the concept will spur more researches on the cathodes that share the same sublattice.

19.
Adv Mater ; 35(22): e2207904, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36944045

RESUMO

Controllable anionic redox for a transformational increase in the energy density is the pursuit of next generation Li-ion battery cathode materials. Its activation mechanism is coupled with the local coordination environment around O, which posts experimental challenges for control. Here, the tuning capability of anionic redox is shown by varying O local environment via experimentally controlling the density of stacking faults in Li2 MnO3 , the parent compound of Li-rich oxides. By combining computational analysis and spectroscopic study, it is quantitatively revealed that more stacking faults can trigger smaller LiOLi bond angles and larger LiO bond distance in local Li-rich environments and subsequently activate oxygen redox reactivity, which in turn enhances the reactivity of Mn upon the following reduction process. This study highlights the critical role of local structure environment in tuning the anionic reactivity, which provides guidance in designing high-capacity layered cathodes by appropriately adjusting stacking faults.

20.
J Am Chem Soc ; 2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36734666

RESUMO

Heteroepitaxial core-shell structure is conducive to combining the advantages of the epilayer and the substrate, creating a novel multifunctionality for catalysis application. Herein, we report a pseudomorphic-Pt atomic layer (PmPt) epitaxially growing on an IrPd-core matrix (PmPt@IrPd/C) as an efficient and stable catalyst for alkaline hydrogen oxidation reaction that exhibits ∼29.2 times more mass activity enhancement than that of benchmark Pt/C. The PmPt@IrPd/C catalyst also gives rise to ∼25.0 times more enhancement than Pt/C during a 50,000-cycle accelerated stability test. This robust stability originates from the resistance to carbon corrosion owing to the stronger H2O interaction instead of carbon oxide (COx) poison species, and the modulated hydroxyl (OH*) adsorption could inhibit the OH* species from shuffling the surface Pt atoms away from the substrate. Moreover, the anion-exchange membrane fuel cells assembled by PmPt@IrPd/C with an ultralow Pt loading of 0.009 mgPt cm-2 in the anode can deliver a power density of 1.27 W cm-2.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...