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1.
Langmuir ; 40(28): 14355-14367, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38961770

RESUMO

The creation of ordered collective vacancies in experiment proves challenging within a two-dimensional lattice, resulting in a limited understanding of their impact on catalyst performance. Motivated by the successful experimental synthesis of monolayer molybdenum borides with precisely ordered metal vacancies [Zhou et al. Science 2021, 373, 801-805] through dealloying, the nitrogen reduction reaction (NRR) in monolayer borides was systematically investigated to elucidate the influence of such ordered metal vacancies on catalytic reactions and the underlying mechanisms. The results reveal that the N-containing intermediates tend to dissociate, facilitating the NRR process with reduced UL. The emergence of ordered metal vacancies modulates the electronic properties of the catalyst and partially facilitates the decomposition of N-containing intermediates. However, the UL for NRR in Mo4/3B2 and W4/3B2 exhibits a significant increase. The compromised electrochemical performance is explained through the development of a simple electronic descriptor of the d-p band center (ΔdM-pB). Among these materials, Mo4/3Sc2/3B2 exhibits the most superior catalytic activity with a UL of -0.5 V and favorable NRR selectivity over the HER. Our results provide mechanistic insights into the role of ordered metal vacancies in transition-metal boride for the NRR and highlight a novel avenue toward the rational design of superior NRR catalysts.

2.
Chemistry ; 29(43): e202301055, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37208940

RESUMO

Low band gap materials have always been a focus of attention due to their potential applications in various fields. In this work, a series of asymmetric bistricyclic aromatic ene (BAE) compounds with fluorenylidene-cyclopentadithiophene (FYT) skeleton were facially synthesized, which were modified with different substituents (-OMe, -SMe). The FYT core exhibit twisted C=C bond with dihedral angles around 30°, and the introduction of -SMe group can provide additional S⋅⋅⋅S interaction between molecules, which is conducive to the charge transporting. The UV-Vis spectra, electrochemistry and photoelectron spectroscopy revealed that these compounds have relatively narrow band gaps, particularly, the -SMe modified compounds have slightly lower HOMO and Fermi energy levels than that of the -OMe modified compounds. Furthermore, PSCs devices were fabricated with the three compounds as HTMs, and FYT-DSDPA exhibit the best performance among them, revealing the fine-tuning band structure could influence properties of HTMs.

3.
Chemphyschem ; 24(8): e202200864, 2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-36562718

RESUMO

Considering the pivotal role of ammonia in the modern chemical industry, designing effective catalysts for the N2 -to-NH3 conversion stimulates great research enthusiasms. In this work, by means of density functional theory calculations, we systematically investigated the electrocatalysis of six-coordinated transition metal atom anchored graphene for nitrogen fixation. The free energy analysis shows that the ZrN6 configuration has a good activity toward ammonia synthesis under overpotential of 0.51 V. According to the electron transfer analysis, ZrN6 site plays a bridging role in charge transfer between the functional graphene and the reactant. Furthermore, the presence of N6 coordination increases the electron accumulation on the NNHx intermediates, which weakens the intermolecular N-N bond, reducing the thermodynamic barrier of protonation process. This work provides a basic understanding of the interaction between transition metal and the adjacent coordination in tuning the reactivity.

4.
Eur Radiol ; 33(11): 7952-7966, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37314471

RESUMO

OBJECTIVES: To evaluate whether MRI-based T stage (TMRI), [18F]FDG PET/CT-based N (NPET/CT), and M stage (MPET/CT) are superior in NPC patients' prognostic stratification based on long-term survival evidences, and whether TNM staging method involving TMRI + NPET/CT + MPET/CT could improve NPC patients' prognostic stratification. METHODS: From April 2007 to December 2013, 1013 consecutive untreated NPC patients with complete imaging data were enrolled. All patients' initial stages were repeated based on (1) the NCCN guideline recommended "TMRI + NMRI + MPET/CT" ("MMP") staging method; (2) the traditional "TMRI + NMRI + Mconventional work-up (CWU)" ("MMC") staging method; (3) the single-step "TPET/CT + NPET/CT + MPET/CT" ("PPP") staging method; or (4) the "TMRI + NPET/CT + MPET/CT" ("MPP") staging method recommended in present research. Survival curve, ROC curve, and net reclassification improvement (NRI) analysis were used to evaluate the prognosis predicting ability of different staging methods. RESULTS: [18F]FDG PET/CT performed worse on T stage (NRI = - 0.174, p < 0.001) but better on N (NRI = 0.135, p = 0.004) and M stage (NRI = 0.126, p = 0.001). The patients whose N stage upgraded by [18F]FDG PET/CT had worse survival (p = 0.011). The "TMRI + NPET/CT + MPET/CT" ("MPP") method performed better on survival prediction when compared with "MMP" (NRI = 0.079, p = 0.007), "MMC" (NRI = 0.190, p < 0.001), or "PPP" method (NRI = 0.107, p < 0.001). The "TMRI + NPET/CT + MPET/CT" ("MPP") method could reclassify patients' TNM stage to a more appropriate stage. The improvement is significant in patients with more than 2.5-years follow-up according to the time-dependent NRI values. CONCLUSIONS: The MRI is superior to [18F]FDG PET/CT in T stage, and [18F]FDG PET/CT is superior to CWU in N/M stage. The "TMRI + NPET/CT + MPET/CT" ("MPP") staging method could significantly improve NPC patients' long-term prognostic stratification. CLINICAL RELEVANCE STATEMENT: The present research provided long-term follow-up evidence for benefits of MRI and [18F]FDG PET/CT in TNM staging for nasopharyngeal carcinoma, and proposes a new imaging procedure for TNM staging incorporating MRI-based T stage and [18F]FDG PET/CT-based N and M stage, which significantly improves long-term prognostic stratification for patients with NPC. KEY POINTS: • The long-term follow-up evidence of a large-scale cohort was provided to evaluate the advantages of MRI, [18F]FDG PET/CT, and CWU in the TNM staging of nasopharyngeal carcinoma. • A new imaging procedure for TNM stage of nasopharyngeal carcinoma was proposed.


Assuntos
Neoplasias Nasofaríngeas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Carcinoma Nasofaríngeo/diagnóstico por imagem , Carcinoma Nasofaríngeo/patologia , Prognóstico , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18 , Compostos Radiofarmacêuticos , Tomografia por Emissão de Pósitrons/métodos , Estadiamento de Neoplasias , Imageamento por Ressonância Magnética , Neoplasias Nasofaríngeas/patologia
5.
Inorg Chem ; 62(18): 7061-7068, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37121904

RESUMO

A new series of O∧C-chelate tetra-coordinated boranes with naphtha-aldehyde as the chelate backbone have been synthesized. Their photophysical and photochemical properties have been examined, which show that all of the compounds can undergo both photo and thermal transformations, generating aryl-migrated [1,2]oxaborinine derivatives as the major products. 1,3-Sigmatropic shifts and an intramolecular nucleophilic addition mechanism are proposed for the photochemical and thermal conversion pathways, respectively.

6.
Phys Chem Chem Phys ; 25(42): 29310-29314, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37876304

RESUMO

Understanding the physical origin of materials exhibiting different properties at the mesoscale is of great significance for the design and fabrication of multifunctional quantum devices. In this work, we proposed a simple model without any adjustable parameters to describe the size (D) dependence of Debye temperature ΘD(D) of metallic nanocrystals. ΘD(D) drops with the decrease of D, which is verified by relevant experimental and simulation results. In addition, we found that the difference in the size dependence of ΘD(D) of different metal elements is determined by the ratio of the solid/liquid interface energy γsl and surface stress f, and the smaller the D of the nanocrystals, the greater the influence of γsl/f on ΘD(D)/ΘD.

7.
Phys Chem Chem Phys ; 25(2): 1123-1132, 2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36514966

RESUMO

Na-ion batteries (SIBs) are emerging as a promising alternative to Li-ion batteries for large-scale energy storage in light of abundant Na resources and their low cost. Development of appropriate electrode materials that can conquer some critical issues such as low theoretical storage capacity and sluggish redox kinetics resulting from the larger radius of Na is urgently needed for their practical applications. In this work, boron-rich 2D BxN (x = 2, 3, and 5) has been explored as promising anode materials for high-performance SIBs based on density functional theory calculations. BxN electrodes exhibit moderate affinity toward Na-ions with adsorption energies of -0.41 to -1.21 eV, which allows stable Na-ion intercalation without the formation of metal dendrites. Moreover, both B3N and B5N deliver low diffusion barriers (0.28 and 0.08 eV) for Na-ion migration, guaranteeing a high charging/discharging rate. More importantly, these BxN anodes exhibit not only a remarkably high theoretical capacity of 1129-1313 mA h g-1 but also a low open-circuit voltage (0.45-0.87 V), which is important to achieve high energy density. AIMD simulations have confirmed the excellent cyclability of BxN electrodes during reversible lithiation/delithiation. These results suggested that the BxN electrode could be used as a new lightweight SIB anode with high capacity, cyclability, and desired rate performance.

8.
Phys Chem Chem Phys ; 25(41): 27994-28005, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37819217

RESUMO

Borophene, the lightest two-dimensional material, exhibits exceptional storage capacity as an anode material for sodium-ion batteries (NIBs) and potassium-ion batteries (PIBs). However, the pronounced surface activity gives rise to strong interfacial bonding between borophene and the metal substrate it grows on. Incorporation of heterogeneous atoms capable of forming strong bonds with boron to increase borophene stability while preserving its intrinsic metallic conductivity and high theoretical capacity remains a great challenge. In this study, a particle swarm optimization (PSO) method was employed to determine several new two-dimensional monolayer boron phosphides (BxP, x = 3-6) with rich boron components. The obtained BxP has great potential to be used as an anode material for sodium-ion batteries/potassium-ion batteries (SIBs/PIBs), according to DFT calculations. BxP demonstrates remarkable stability compared with borophene which ensures their feasibility of experimental synthesis. Moreover, B5P and B6P exhibit high electronic conductivity and ionic conductivity, with migration energy barriers of 0.20 and 0.21 eV for Na ions and 0.07 eV for K ions. Moreover, the average open circuit voltage falls within a favorable range of 0.25-0.73 V, which results in a high storage capacity of 1119-2103 mA h g-1 for SIBs and 631-839 mA h g-1 for PIBs. This study paves the way for exploring boron-rich 2D electrode materials for energy applications and provides valuable insights into the functionalization and stabilization of borophene.

9.
Mol Carcinog ; 61(5): 508-523, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35129856

RESUMO

Kidney renal clear cell carcinoma (KIRC) is one of the most common malignancies, and there is still a lack of effective biomarkers for early detection and prognostic prediction. In here, we compared the characteristics of RNA sequencing data sets of KIRC samples based on the tumor suppressor gene phosphatase and tensin homolog (PTEN). The 1016 long noncoding RNAs, 48 microRNAs (miRNAs), and 2104 messenger RNAs associated with PTEN were identified and these genes were differentially expressed between tumor and paracancerous tissues. The most relevant pathway was found to be WDFY3-AS2 - miR-21-5p/miR-221-3p/miR-222-3p - TIMP3 according to the rules of competing endogenous RNA (ceRNA) regulation. WDFY3-AS2 and TIMP3 expression were positively correlated and reduced in KIRC samples, while miR-21-5p, miR-221-3p, and miR-222-3p were relatively highly expressed. The relatively low expression of WDFY3-AS2 and TIMP3 in KIRC were associated with poor prognosis in KIRC patients, while higher expression of miR-21-5p, miR-221-3p, and miR-222-3p predicted reduced survival (p < 0.05). Univariate and multivariate Cox regression analysis showed that lower expression of WDFY3-AS2 and TIMP3 was significantly related to tumor grade, tumor size, lymph node metastasis, distant metastasis, and TNM stage. The expression of TIMP3 in KIRC tissues was also verified by immunohistochemistry, and the results were consistent with our analytical data. In summary, this study constructed a new model with clinical predictive value and identified the WDFY3-AS2/TIMP3 pathway that was closely associated with the prognosis of KIRC, which could serve as a promising biomarker for the diagnosis and treatment of KIRC.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , MicroRNAs , RNA Longo não Codificante , Proteínas Adaptadoras de Transdução de Sinal , Proteínas Relacionadas à Autofagia/genética , Biomarcadores , Carcinogênese/genética , Carcinoma de Células Renais/patologia , Transformação Celular Neoplásica/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Rim/metabolismo , Neoplasias Renais/patologia , Masculino , MicroRNAs/genética , MicroRNAs/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Inibidor Tecidual de Metaloproteinase-3/genética , Inibidor Tecidual de Metaloproteinase-3/metabolismo
10.
Inorg Chem ; 61(28): 10705-10712, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35772025

RESUMO

Dimesitylboryl-acceptor (A) and diarylamine-donor (D) substituents are introduced at α positions of BN-doped tetrathienonaphthalene in the same and opposite directions of the B-N bond, namely, B-BN-N and N-BN-B, in order to demonstrate how the substitution patterns influence the photophysical properties. The photophysical and electrochemical properties of these D-π-A molecules have been investigated in detail, aided by UV-vis absorption and fluorescence spectroscopy as well as cyclic voltammetry. We find that both B-BN-N and N-BN-B show the typical intramolecular charge transfer emission. N-BN-B exhibits strong fluorescence with a narrower band gap and stronger Lewis acidity than that of B-BN-N. DFT calculations help give a reasonable explanation that subtle differences in the electronic structure of the host skeleton could also influence the substituents and feed back this effect to the entire molecule.

11.
Phys Chem Chem Phys ; 24(18): 11336-11344, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35485926

RESUMO

To clarify the interface melting mechanism, a unified analytical expression was developed to describe the depression and superheating of Tm(D) functions for metallic nanoparticles, nanostructures, and nanoparticles embedded in a coherent or incoherent interface. Tm(D) functions are determined by the sign of γss, fss (or γsl and fsl), and D0 as caused by the change of interface environments. We found that there is TCIm(D) > TNSm(D) > TIIm(D) > TNPsm(D) for Ag nanocrystals within different interfaces. Moreover, for a given size, Tm(D)/Tm(∞) decreases with the reduction of γss/fss for nanoparticles, nanostructures and nanoparticles embedded in incoherent interfaces, while an opposite trend occurs for the coherent interfaces. In addition, we also found that there is TNPsm(D)/Tm(∞) < TIIm(D)/Tm(∞) < TNSm(D)/Tm(∞), which is in agreement with the relation of γNPssl/fNPssl < γIIss/fIIss < γNSss/fNSss. By analyzing the γss(D) (or γsl(D)), fss(D) (or fsl(D)) and γss(D)/fss(D) (or γsl(D)/fsl(D)) functions of Ag nanocrystals and comparing with their Tm(D) functions, it is found that there is a high consistency between the variation of γss(D)/fss(D) (γsl(D)/fsl(D)) and Tm(D)/Tm, which reveals that the size dependence of Tm(D)/Tm is determined by γss(D)/fss(D) (or γsl(D)/fsl(D)). Our predictions show a good agreement with the available theoretical and experimental results.

12.
Eur J Nucl Med Mol Imaging ; 48(8): 2586-2598, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33420610

RESUMO

PURPOSE: This study aimed to establish an effective nomogram to predict primary distant metastasis (DM) in patients with nasopharyngeal carcinoma (NPC) to guide the application of PET/CT. METHODS: In total, 3591 patients with pathologically confirmed NPC were consecutively enrolled. The nomogram was constructed based on 1922 patients treated between 2007 and 2014. Multivariate logistical regression was applied to identify the independent risk factors of DM. The predictive value of the nomogram was evaluated using the concordance index (C-index), calibration curve, probability density functions (PDFs), and clinical utility curve (CUC). The results were validated in 1669 patients enrolled from 2015 to 2016. Net reclassification improvement (NRI) was applied to compare performances of the nomogram with other clinical factors. The best cut-off value of the nomogram chosen for clinical application was analyzed. RESULTS: A total of 355 patients showed primary DM among 3591 patients, yielding an incidence rate of 9.9%. Sex, N stage, EBV DNA level, lactate dehydrogenase level, and hemoglobin level were independent predictive factors for primary DM. C-indices in the training and validation cohort were 0.796 (95% CI, 0.76-0.83) and 0.779 (95% CI, 0.74-0.81), respectively. The NRI indices demonstrated that this model had better predictive performance than plasma EBV DNA level and N stage. We advocate for a threshold probability of 3.5% for guiding the application of PET/CT depending on the clinical utility analyses. CONCLUSION: This nomogram is a useful tool to predict primary DM of NPC and guide the clinical application of PET/CT individually at the initial staging.


Assuntos
Neoplasias Nasofaríngeas , Nomogramas , Fluordesoxiglucose F18 , Humanos , Carcinoma Nasofaríngeo/diagnóstico por imagem , Neoplasias Nasofaríngeas/diagnóstico por imagem , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Prognóstico
13.
BMC Cancer ; 21(1): 534, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975558

RESUMO

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a malignancy predominantly associated with infection by the Epstein-Barr virus (EBV). Approximately 12,900 new cases of NPC occur each year, with more than 70% of cases occurring in the east and southeast Asia. NPC is different from ordinary head and neck squamous cell carcinoma due to its particular biological properties and it is highly sensitive to radiotherapy. With the development of RT technology, the 3-year local control rate and survival rates of non-metastatic NPC reached 80-90% in the intensity-modulated RT (IMRT) era. However, whether distant metastatic NPC (de novo mNPC, dmNPC) should receive locoregional RT (LRRT) needs to be clarified. RESULTS: Multivariate analysis identified three independent prognostic factors: Epstein-Barr virus (EBV) DNA, number of metastatic lesions, and number of metastatic organs. Through these factors, all patients were successfully divided into 3 subgroups: low-risk (single metastatic organ, EBV DNA ≤ 25,000 copies/ml, and ≤ 5 metastatic lesions), intermediate-risk (single metastatic organ, EBV DNA > 25,000 copies/ml, and ≤ 5 metastatic lesions), and high-risk (multiple metastatic organs or > 5 metastatic lesions or both). By comparing LRRT and non-LRRT groups, statistical differences were found in OS in the low-risk and intermediate-risk subgroups (p = 0.039 and p = 0.010, respectively) but no significant difference was found in OS in the high-risk subgroup (p = 0.076). Further multivariate analysis of different risk stratifications revealed that LRRT can improve OS of low- and intermediate-risk subgroups. CONCLUSIONS: The risk stratification of dmNPC may be used as a new prognostic factor to help clinicians organize individualized LRRT treatment to improve the survival outcomes of dmNPC patients.


Assuntos
DNA Viral/análise , Herpesvirus Humano 4/isolamento & purificação , Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/radioterapia , Carga Tumoral , Adolescente , Adulto , Idoso , Feminino , Herpesvirus Humano 4/genética , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo/mortalidade , Carcinoma Nasofaríngeo/patologia , Carcinoma Nasofaríngeo/virologia , Neoplasias Nasofaríngeas/mortalidade , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/virologia , Prognóstico , Estudos Retrospectivos , Adulto Jovem
14.
Eur Radiol ; 31(7): 5222-5233, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33416977

RESUMO

OBJECTIVES: The value of using PET/CT for staging of stage I-II NPC remains unclear. Hence, we aimed to investigate the survival benefit of PET/CT for staging of early-stage NPC before radical therapy. METHODS: A total of 1003 patients with pathologically confirmed NPC of stages I-II were consecutively enrolled. Among them, 218 patients underwent both PET/CT and conventional workup ([CWU], head-and-neck MRI, chest radiograph, liver ultrasound, bone scintigraphy) before treatment. The remaining 785 patients only underwent CWU. The standard of truth (SOT) for lymph node metastasis was defined by the change of size according to follow-up MRI. The diagnostic efficacies were compared in 218 patients who underwent both PET/CT and CWU. After covariate adjustment using propensity scoring, a cohort of 872 patients (218 with and 654 without pre-treatment PET/CT) was included. The primary outcome was overall survival based on intention to treat. RESULTS: Retropharyngeal lymph nodes were metastatic based on follow-up MRI in 79 cases. PET/CT was significantly less sensitive than MRI in detecting retropharyngeal lymph node lesions (72.2% [62.3-82.1] vs. 91.1% [84.8-97.4], p = 0.004). Neck lymph nodes were metastatic in 89 cases and PET/CT was more sensitive than MRI (96.6% [92.8-100.0] vs. 76.4% [67.6-85.2], p < 0.001). In the survival analyses, there was no association between pre-treatment PET/CT use and improved overall survival, progression-free survival, local relapse-free survival, regional relapse-free survival, and distant metastasis-free survival. CONCLUSIONS: This study showed PET/CT is of little value for staging of stage I-II NPC patients at initial imaging. KEY POINTS: • PET/CT was more sensitive than MRI in detecting neck lymph node lesions whereas it was significantly less sensitive than MRI in detecting retropharyngeal lymph node lesions. • No association existed between pre-treatment PET/CT use and improved survival in stage I-II NPC patients.


Assuntos
Neoplasias Nasofaríngeas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Estudos de Casos e Controles , Fluordesoxiglucose F18 , Humanos , Linfonodos/patologia , Carcinoma Nasofaríngeo/diagnóstico por imagem , Neoplasias Nasofaríngeas/diagnóstico por imagem , Neoplasias Nasofaríngeas/patologia , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Tomografia Computadorizada por Raios X
15.
Angew Chem Int Ed Engl ; 60(43): 23388-23393, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34370386

RESUMO

PtSe2 is a typical noble metal dichalcogenide (NMD) that holds promising possibility for next-generation electronics and photonics. However, when applied in hydrogen evolution reaction (HER), it exhibits sluggish kinetics due to the insufficient capability of absorbing active species. Here, we construct PtSe2 /Pt heterointerface to boost the reaction dynamics of PtSe2 , enabled by an in situ electrochemical method. It is found that Se vacancies are induced around the heterointerface, reducing the coordination environment. Correspondingly, the exposed Pt atoms at the very vicinity of Se vacancies are activated, with enhanced overlap with H 1s orbital. The adsorption of H. intermediate is thus strengthened, achieving near thermoneutral free energy change. Consequently, the as-prepared PtSe2 /Pt exhibits extraordinary HER activity even superior to Pt/C, with an overpotential of 42 mV at 10 mA cm-2 and a Tafel slope of 53 mV dec-1 . This work raises attention on NMDs toward HER and provides insights for the rational construction of novel heterointerfaces.

16.
Chemphyschem ; 21(12): 1235-1242, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32255234

RESUMO

Developing efficient electrocatalysts for nitrogen reduction reaction (NRR) at ambient conditions is crucial for NH3 synthesis. In this manuscript, the NRR performance of the transition metal anchored MoS2 monolayer with 1T atomic structure (1T-MoS2 ) is systematically evaluated by density functional theory computations. Our results reveal that the V decorated 1T-MoS2 exhibits the outstanding catalytic activity toward NRR via distal mechanism where the corresponding onset potential is 0.66 V, being superior to the commercial Ru material. Furthermore, the powerful binding energy between the V atom and the 1T-MoS2 provides the good resistance against clustering of the V dopant, indicating its stability. Overall, this work provides a potential alternative for the application of NH3 synthesis.

17.
Chemphyschem ; 21(12): 1217, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32548974

RESUMO

The front cover artwork is provided by the groups of Prof. BeiBei, Xiao and Lei, Yang (Jiangsu University of Science and Technology, China) as well as Dr. ErHong, Song (Shanghai Institute of Ceramics, Chinese Academy of Sciences, China). The image shows that the environmental-friendly N2 -to-NH3 conversion is achieved by the V decorated MoS2 monolayer with the 1T atomic configuration, featured by the effective electrocatalysis in combination with the good electronic conductivity. Read the full text of the Article at 10.1002/cphc.202000147.

18.
Phys Chem Chem Phys ; 21(42): 23742-23748, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31637382

RESUMO

Polypyridyl transition metal complexes are well-established homogeneous electrocatalysts for the reduction of CO2. In this work, the relationship between the transition metal (including V, Cr, Mn, Nb, Mo, Ta, W, and Re) and the catalytic activity has been theoretically investigated using density functional theory. It is found that the transition metal center determines the catalytic activity of M(bpy)(CO)4. Among the eight metal complexes, Re(bpy)(CO)4 and Mn(bpy)(CO)4 exhibit better catalytic activity due to the weaker adsorption strength of CO and lower d-band center, which makes it easier to activate the metal complex and results in a lower reaction free energy of the rate-determining step at the reduction potential. We believe that these results can provide guidelines for the design of novel electrocatalysts for CO2 reduction.

19.
Phys Chem Chem Phys ; 20(37): 24427-24433, 2018 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-30221300

RESUMO

Borophenes, which are two-dimensional boron counterparts made of the three synthetic polymorphs T, ß12 and χ3, have been considered as potential anode materials in Li-ion batteries with extremely high capacities. However, Li hopping on ß12 and χ3 borophenes is quite slow with high energy barriers (around 0.6 eV), thus preventing the application of these borophenes in the fast charging realm. Here, we have used halogen functionalization in an attempt to boost the sluggish Li-ion diffusion dynamics in the prototype χ3 borophene system. Halogens bind strongly to χ3 borophene with substantial electron transfer from the latter to the former, thereby leading to local electron deficiency in the χ3 borophene. The synergy of electron extraction from χ3 borophene and the electrostatic attraction between halogens and Li results in an enhanced affinity between χ3 borophene and Li as well as a reduction in the Li-ion hopping barrier. Iodine is the preferred dopant, for which most diffusion paths exhibit energy barriers typically smaller than 0.2 eV. Our results suggest that halogen incorporation could facilitate intercalation and de-intercalation of Li-ions in borophene-based anode materials.

20.
Phys Chem Chem Phys ; 20(48): 30304-30311, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30484451

RESUMO

Motived by the recent experimental fabrication of two-dimensional boron hydride (BH) sheets (Nishino et al., J. Am. Chem. Soc. 2017, 139, 13761), we explore the feasibility of pristine and Li doped BH sheets as a hydrogen storage medium within the framework of density functional theory. BH shows an unexpected high affinity to Li with a binding energy of -2.38 eV in comparison to other alkali and alkaline earth metals (Na, K, Ca, Mg and Al), much larger than its bulk cohesive energy (-1.63 eV). Energy barriers of Li diffusion on BH are also determined to be around 1.12 eV, showing both high dynamic and thermodynamic stability without the issue of cluster formation. Moreover, Li decorated BH is expected to achieve a high theoretical gravimetric density of 11.57 wt% with an average H2 adsorption energy of -0.17 eV, holding great potential in massive hydrogen storage. In addition to the storage, thermodynamic analysis on the desorption behaviors of H2 molecules is performed via N-P-T diagram, which demonstrates that most of the H2 molecules (8.30 wt%) could be released at 3 atm/100 °C. Thus, the Li-decorated BH sheets are expected to be applied as an efficient medium for hydrogen storage under ambient conditions.

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