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1.
Proc Natl Acad Sci U S A ; 119(22): e2120716119, 2022 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-35605120

RESUMEN

SignificanceFor oxide catalysts, it is important to elucidate and further control their atomic structures. In this work, well-defined CrO2 bilayer islands and Cr2O7 dinuclear clusters have been grown on Au(111) and unambiguously identified by scanning tunneling microscopy and theoretical calculations. Upon cycled redox treatments, the two kinds of oxide nanostructures can be reversibly transformed. It is interesting to note that both Cr oxides do not exist in bulk but need to be stabilized by the metal surface and the specific environment. Our results suggest that both redox atmosphere and interface confinement effects can be used to construct an oxide nanostructure with the specific chemical state and structure.

2.
Nano Lett ; 24(28): 8687-8695, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-38973752

RESUMEN

Electrocatalytic nitrate reduction is an efficient way to produce ammonia sustainably. Herein, we rationally designed a copper metalloporphyrin-based hydrogen-bonded organic framework (HOF-Cu) through molecular engineering strategies for electrochemical nitrate reduction. As a result, the state-of-the-art HOF-Cu catalyst exhibits high NH3 Faradaic efficiency of 93.8%, and the NH3 production rate achieves a superior activity of 0.65 mmol h-1 cm-2. The in situ electrochemical spectroscopic combined with density functional theory calculations reveals that the dispersed Cu promotes the adsorption of NO3- and the mechanism is followed by deoxidation of NO3- to *NO and accompanied by deep hydrogenation. The generated *H participates in the deep hydrogenation of intermediate with fast kinetics as revealed by operando electrochemical impedance spectroscopy, and the competing hydrogen evolution reaction is suppressed. This research provides a promising approach to the conversion of nitrate to ammonia, maintaining the nitrogen balance in the atmosphere.

3.
Small ; : e2402879, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39015053

RESUMEN

Cu-doped Bi2O2CO3 catalyst with copper (Cu) acting an electron hunter for conversion of carbon dioxide into formate is developed. The Cu-Bi2O2CO3 catalyst with hollow microsphere structure extends the duration of CO2 retention on the catalyst, providing a greater number of active sites. It exhibits remarkable performance with conversion efficacy of 98.5% and current density of 800 mA cm-2 across a wide potential window (-0.8 to -1.3 V vs RHE). Density functional theory investigations reveal that the presence of copper (Cu) significantly enhances the charge density at the active sites and influences the local electronic structure of bismuth (Bi), thereby reducing the energy barrier associated with the transformation of *OCHO species into formate.

4.
Small ; : e2403778, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38948957

RESUMEN

Bismuth-based catalysts are effective in converting carbon dioxide into formate via electrocatalysis. Precise control of the morphology, size, and facets of bismuth-based catalysts is crucial for achieving high selectivity and activity. In this work, an efficient, large-scale continuous production strategy is developed for achieving a porous nanospheres Bi2O3-FDCA material. First-principles simulations conducted in advance indicate that the Bi2O3 (111)/(200) facets help reduce the overpotential for formate production in electrocatalytic carbon dioxide reduction reaction (ECO2RR). Subsequently, using microfluidic technology and molecular control to precisely adjust the amount of 2, 5-furandicarboxylic acid, nanomaterials rich in (111)/(200) facets are successfully synthesized. Additionally, the morphology of the porous nanospheres significantly increases the adsorption capacity and active sites for carbon dioxide. These synergistic effects allow the porous Bi2O3-FDCA nanospheres to stably operate for 90 h in a flow cell at a current density of ≈250 mA cm- 2, with an average Faradaic efficiency for formate exceeding 90%. The approach of theoretically guided microfluidic technology for the large-scale synthesis of finely structured, efficient bismuth-based materials for ECO2RR may provide valuable references for the chemical engineering of intelligent nanocatalysts.

5.
Soft Matter ; 20(3): 511-522, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38113054

RESUMEN

Exploiting the interplay of anisotropic diamagnetic susceptibility of liquid crystalline monomers and site selective photopolymerization enables the fabrication of 3D freeforms with highly refined microstructures. Utilizing chain transfer agents in the mesogenic inks presents a pathway for broadly tuning the mechanical properties of liquid crystalline polymers and their response to stimuli. In particular, the combination of 1,4-benzenedimethanethiol and tetrabromomethane is shown to enable voxelated blueprinting of molecular order, while allowing for a modulation of the crosslink density and the mechanical properties. The formulation of these monomers allows for the resolution of the voxels to approach the limits set by the coherence lengths defined by the anchoring from surfaces. These compositions demonstrate the expected thermotropic responses while allowing for their functionalization with photochromic switches to elicit photomechanical responses. Actuation strains are shown to outstrip that accomplished with prior systems that did not access chain transfer agents to modulate the structure of the macromolecular network. Test cases of this system are shown to create freeform actuators that exploit the refined director patterns during high-resolution printing. These include topological defects, hierarchically-structured light responsive grippers, and biomimetic flyers whose flight dynamics can be actively modulated via irradiation with light.

6.
Brain Topogr ; 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38955901

RESUMEN

Methamphetamine (MA) is a neurological drug, which is harmful to the overall brain cognitive function when abused. Based on this property of MA, people can be divided into those with MA abuse and healthy people. However, few studies to date have investigated automatic detection of MA abusers based on the neural activity. For this reason, the purpose of this research was to investigate the difference in the neural activity between MA abusers and healthy persons and accordingly discriminate MA abusers. First, we performed event-related potential (ERP) analysis to determine the time range of P300. Then, the wavelet coefficients of the P300 component were extracted as the main features, along with the time and frequency domain features within the selected P300 range to classify. To optimize the feature set, F_score was used to remove features below the average score. Finally, a Bidirectional Long Short-term Memory (BiLSTM) network was performed for classification. The experimental result showed that the detection accuracy of BiLSTM could reach 83.85%. In conclusion, the P300 component of EEG signals of MA abusers is different from that in normal persons. Based on this difference, this study proposes a novel way for the prevention and diagnosis of MA abuse.

7.
Phys Chem Chem Phys ; 26(8): 6991-7000, 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38344948

RESUMEN

The synthesis of ammonia via an electrochemical nitrogen reduction reaction (NRR, N2 + 6H+ + 6e- → 2NH3), which can weaken but not directly break an inert NN bond under mild conditions via multiple progressive protonation steps, has been proposed as one of the most attractive alternatives for the production of NH3. However, the development of appropriate catalyst materials is a major challenge in the application of NRRs. Recently, single- or multi-metal atoms anchored on two-dimensional (2D) substrates have been demonstrated as ideal candidates for facilitating NRRs. In this work, by applying spin-polarized density functional theory and ab initio molecular dynamic simulations, we systematically explored the performances of nine types of transition metal multi-atoms anchored on a recently developed 2D biphenylene (BPN) sheet in nitrogen reduction. Structural stability and NRR performance catalyzed by TMn (TM = V, Fe, Ni, Mo, Ru, Rh, W, Re, Ir; n = 1-4) clusters anchored on BPN sheets were systematically explored. After a strict six-step screening strategy, it was found that W2, Ru2 and Mo4 clusters loaded on BPN demonstrate superior potential for nitrogen reduction with extremely low onset potentials of -0.26, -0.36 and -0.17 V, respectively. Electronic structure analysis revealed that the enhanced ability of these multi-atom catalysts to effectively capture and reduce the N2 molecule can be attributed to bidirectional charge transfer between the d orbitals of transition metal atoms and molecular orbitals of the adsorbed N2 through a "donation-back donation" mechanism. Our findings highlight the value of BPN sheets as a substrate for designing multi-atom nitrogen reduction reaction catalysts.

8.
Biomed Chromatogr ; 38(7): e5880, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38634147

RESUMEN

Iridoid glycosides extract, which is the main active extract of Ajuga decumbens Thunb, has been proved to have anti-breast cancer activity in previous studies. However, it is still unknown whether 8-O-acetylharpagide, a main active compound in the extract, has anti-breast cancer activity. In this study, 4 T1 breast cancer mice model was first successfully established. Then the anti-breast cancer effect of 8-O-acetylharpagide was systematically investigated. Feces were collected for metabolomics and 16S rRNA analysis to assess the potential mechanism. The results showed that 8-O-acetylharpagide was effective in reducing 4 T1 mouse tumor volume and weight compared with the model group. Metabolome analysis revealed 12 potential metabolite biomarkers in feces, mainly involved in primary bile acid biosynthesis and arachidonic acid metabolism. The 16S rRNA sequencing results demonstrated that 8-O-acetylharpagide modulated the abundance of the intestinal flora in 4 T1 mice. Spearman correlation analysis showed that calcitriol and prostaglandin G2 strongly correlated with Akkermansia, Firmicutes and Muribaculum. Overall, the active compound 8-O-acetylharpagide could inhibit significantly breast cancer growth in 4 T1 breast cancer model mice. The mechanism of the anti-breast cancer effect of 8-O-acetylharpagide may be related to the regulation of primary bile acid biosynthesis and arachidonic acid metabolism and modulation of the abundance of Akkermansia and Firmicutes.


Asunto(s)
Neoplasias de la Mama , Metaboloma , Animales , Ratones , Femenino , Metaboloma/efectos de los fármacos , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Heces/microbiología , Heces/química , Glicósidos Iridoides/farmacología , Glicósidos Iridoides/química , Microbioma Gastrointestinal/efectos de los fármacos , Metabolómica/métodos , Línea Celular Tumoral , Modelos Animales de Enfermedad , Ratones Endogámicos BALB C
9.
J Appl Clin Med Phys ; 25(2): e14153, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37698358

RESUMEN

PURPOSE: This research aimed to develop a prediction model to assess bladder wall dosimetry during radiotherapy for patients with pelvic tumors, thereby facilitating the refinement and evaluation of radiotherapy treatment plans to mitigate bladder toxicity. METHODS: Radiotherapy treatment plans of 49 rectal cancer patients and 45 gynecologic cancer patients were collected, and multiple linear regression analyses were used to generate prediction models for bladder wall dose parameters ( V 10 - 45 G y ( c m 3 ) ${V_{10 - 45Gy\ }}( {{\mathrm{c}}{{\mathrm{m}}^3}} )$ , D m e a n ( Gy ) ${D_{mean}}( {{\mathrm{Gy}}} )$ ). These models were based on the multiscale spatial relationship between the planning target volume (PTV) and the bladder or bladder wall. The proportion of bladder or bladder wall volume overlapped by the different distance expansions of the PTV was used as an indicator of the multiscale spatial relationship. The accuracy of these models was verified in a cohort of 12 new patients, with further refinement of radiotherapy treatment plans using the predicted values as optimization parameters. Model accuracy was assessed using root mean square error (RMSE) and mean percentage error (MPE). RESULTS: Models derived from individual disease data outperformed those derived from combined datasets. Predicted bladder wall dose parameters were accurate, with the majority of initial calculated values for new patients falling within the 95% confidence interval of the model predictions. There was a robust correlation between the predicted and actual dose metrics, with a correlation coefficient of 0.943. Using the predicted values to optimize treatment plans significantly reduced bladder wall dose (p < $\ < \ $ 0.001), with bladder wall D mean ( G y ) ${D_{{\mathrm{mean}}}}( {Gy} )$ and V 10 - 45 G y ( c m 3 ) ${V_{10 - 45Gy\ }}( {{\mathrm{c}}{{\mathrm{m}}^3}} )$ decreasing by 2.27±0.80 Gy (5.8%±1.8%) and 2.96±2.05 cm3 (7.9%±5.4%), respectively. CONCLUSION: The formulated prediction model provides a valuable tool for predicting and minimizing bladder wall dose and for optimizing and evaluating radiotherapy treatment plans for pelvic tumor patients. This approach holds promise for reducing bladder toxicity and potentially improving patient outcomes.


Asunto(s)
Radioterapia Conformacional , Radioterapia de Intensidad Modulada , Humanos , Femenino , Vejiga Urinaria , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador
10.
J Allergy Clin Immunol ; 152(1): 195-204.e3, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36804390

RESUMEN

BACKGROUND: Histamine is a critical mediator of anaphylaxis, a neurotransmitter, and a regulator of gastric acid secretion. Histidine decarboxylase is a rate-limiting enzyme for histamine synthesis. However, in vivo regulation of Hdc, the gene that encodes histidine decarboxylase, is poorly understood. OBJECTIVE: We sought to investigate how enhancers regulate Hdc gene transcription and histamine synthesis in resting conditions and in a mouse model of anaphylaxis. METHODS: H3K27 acetylation histone modification and chromatin accessibility were used to identify candidate enhancers. The enhancer activity of candidate enhancers was measured in a reporter gene assay, and the function enhancers were validated by CRISPR deletion. RESULTS: Deletion of the GC box, which binds to zinc finger transcription factors, in the proximal Hdc enhancer reduced Hdc gene transcription and histamine synthesis in mouse and human mast cell lines. Mast cells, basophils, brain cells, and stomach cells from GC box-deficient mice transcribed the Hdc gene much less than similar cells from wild-type mice, and Hdc GC box-deficient mice failed to develop anaphylaxis. CONCLUSION: The HDC GC box within the proximal enhancer in the mouse and human HDC gene is essential for Hdc gene transcription, histamine synthesis, and histamine-mediated anaphylaxis in vitro and in vivo.


Asunto(s)
Anafilaxia , Histidina Descarboxilasa , Humanos , Ratones , Animales , Histidina Descarboxilasa/genética , Histamina/metabolismo , Anafilaxia/genética , Línea Celular , Transcripción Genética
11.
BMC Genomics ; 24(1): 592, 2023 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-37798647

RESUMEN

BACKGROUND: Antigenic stimulation through cross-linking the IgE receptor and epithelial cell-derived cytokine IL-33 are potent stimuli of mast cell (MC) activation. Moreover, IL-33 primes a variety of cell types, including MCs to respond more vigorously to external stimuli. However, target genes induced by the combined IL-33 priming and antigenic stimulation have not been investigated in human skin mast cells (HSMCs) in a genome-wide manner. Furthermore, epigenetic changes induced by the combined IL-33 priming and antigenic stimulation have not been evaluated. RESULTS: We found that IL-33 priming of HSMCs enhanced their capacity to promote transcriptional synergy of the IL1B and CXCL8 genes by 16- and 3-fold, respectively, in response to combined IL-33 and antigen stimulation compared to without IL-33 priming. We identified the target genes in IL-33-primed HSMCs in response to the combined IL-33 and antigenic stimulation using RNA sequencing (RNA-seq). We found that the majority of genes synergistically upregulated in the IL-33-primed HSMCs in response to the combined IL-33 and antigenic stimulation were predominantly proinflammatory cytokine and chemokine genes. Moreover, the combined IL-33 priming and antigenic stimulation increase chromatin accessibility in the synergy target genes but not synergistically. Transcription factor binding motif analysis revealed more binding sites for NF-κB, AP-1, GABPA, and RAP1 in the induced or increased chromatin accessible regions of the synergy target genes. CONCLUSIONS: Our study demonstrates that IL-33 priming greatly potentiates MCs' ability to transcribe proinflammatory cytokine and chemokine genes in response to antigenic stimulation, shining light on how epithelial cell-derived cytokine IL-33 can cause exacerbation of skin MC-mediated allergic inflammation.


Asunto(s)
Citocinas , Mastocitos , Humanos , Citocinas/genética , Citocinas/metabolismo , Mastocitos/metabolismo , Interleucina-33/genética , Interleucina-33/metabolismo , Quimiocinas/genética , Cromatina/metabolismo
12.
Parasitology ; 150(8): 661-671, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37051880

RESUMEN

Trematodes of the genus Ogmocotyle are intestinal flukes that can infect a variety of definitive hosts, resulting in significant economic losses worldwide. However, there are few studies on molecular data of these trematodes. In this study, the mitochondrial (mt) genome of Ogmocotyle ailuri isolated from red panda (Ailurus fulgens) was determined and compared with those from Pronocephalata to investigate the mt genome content, genetic distance, gene rearrangements and phylogeny. The complete mt genome of O. ailuri is a typical closed circular molecule of 14 642 base pairs, comprising 12 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes and 2 non-coding regions. All genes are transcribed in the same direction. In addition, 23 intergenic spacers and 2 locations with gene overlaps were determined. Sequence identities and sliding window analysis indicated that cox1 is the most conserved gene among 12 PCGs in O. ailuri mt genome. The sequenced mt genomes of the 48 Plagiorchiida trematodes showed 5 types of gene arrangement based on all mt genome genes, with the gene arrangement of O. ailuri being type I. Phylogenetic analysis using concatenated amino acid sequences of 12 PCGs revealed that O. ailuri was closer to Ogmocotyle sikae than to Notocotylus intestinalis. These data enhance the Ogmocotyle mt genome database and provide molecular resources for further studies of Pronocephalata taxonomy, population genetics and systematics.


Asunto(s)
Ailuridae , Genoma Mitocondrial , Trematodos , Infecciones por Trematodos , Filogenia , Trematodos/clasificación , Trematodos/genética , Infecciones por Trematodos/veterinaria , Animales
13.
Phys Chem Chem Phys ; 25(12): 8853-8860, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36916352

RESUMEN

The stability of two-dimensional (2D) materials upon exposure to ambient conditions is significant for their applications. In this paper, the air stability of the BeO monolayer with and without vacancy defects is carefully studied via DFT calculations. Our results suggest high structural and electronic stability of BeO monolayers upon exposure to O2, N2, CO2 and H2O even with Be vacancies. O vacancies are not favorable in free-standing BeO monolayers and can be easily healed by H2O or CO2 adsorption. Due to the high stability, large band gap and atomic flat surface, BeO monolayers are expected to be an ideal encapsulation material for 2D electronic devices.

14.
Phys Chem Chem Phys ; 25(2): 1214-1219, 2023 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-36524708

RESUMEN

Recently, a new edge structure named ZZ(U) has been evidenced as the lowest-energy structure for bilayer phosphorene nanoribbons (PNRs). Owing to strong quantum confinement effects and edge states, width and edge are the two most important factors that influence the properties of PNRs in nanosized microelectronics. In this study, we systematically investigated the evolution of the electronic properties of bilayer PNRs with different edge configurations as the widths vary. The four types of edges explored include ZZ(Pristine), ZZ(Klein), ZZ(Tube), and newly found ZZ(U). As the widths change from 14 to 40 Å, the ZZ(Pristine) are always metallic with edge states penetrating the Fermi level, while the others are semiconductors. The edge states in ZZ(Klein) are located in the two lowest conduction bands. However, in ZZ(U), the edge states are nearly hidden in the bulk band structure, and its carrier transportation exhibits almost perfect 2D layers, nearly eliminating the U-edge influence. Our results pave the way for phosphorene's utilization in electronics and optoelectronics.

15.
Parasitol Res ; 122(12): 2859-2870, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37801131

RESUMEN

Prosthogonimiasis poses a threat to the reproductive system of poultry and wild birds, which are the definitive hosts of the parasite causing this disease. However, the parasite infection of the second intermediate host (dragonfly), the primary vector of this pathogen, is rarely reported. In this study, the prevalence of Prosthogonimus infection in dragonflies was investigated from June 2019 to October 2022 in Heilongjiang Province, northeast China. The species of metacercariae isolated from dragonfly were identified by morphological characteristics, molecular biology techniques, and animal infection experiments. The results showed that 11 species of dragonflies and one damselfly were identified and among six of the dragonflies infected by Prosthogonimus metacercariae, Sympetrum depressiusculum (28.53%) had the highest infection rate among all positive dragonflies, followed by Sympetrum vulgatum (27.86%) and Sympetrum frequens (20.99%), which are preferred hosts, and the total prevalence was 20.39% (2061/10,110) in Heilongjiang Province. Three species of Prosthogoniumus metacercariae were isolated, including Prosthogonimus cuneatus, Prosthogonimus pullucidus, and Prosthogonimus sp., among which P. cuneatus was the dominant species in dragonflies in Heilongjiang Province. This is the first report on the prevalence of Prosthogonimus in dragonflies in China, which provides baseline data for the control of prosthogonimiasis in Heilongjiang Province and a reference for the prevention of prosthogonimiasis in other areas of China.


Asunto(s)
Odonata , Trematodos , Animales , Metacercarias , China/epidemiología , Prevalencia
16.
J Environ Manage ; 339: 117846, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37054588

RESUMEN

Quantifying phosphorus (P) load from watersheds at a fine scale is crucial for studying P sources in lake or river ecosystems; however, it is particularly challenging for mountain-lowland mixed watersheds. To address this challenge, we proposed a framework to estimate the P load at the grid scale and assessed its risk to surrounding rivers in a typical mountain-lowland mixed watershed (Huxi Region in Lake Taihu Basin, China). The framework coupled three models: the Phosphorus Dynamic model for lowland Polder systems (PDP), the Soil and Water Assessment Tool (SWAT), and the Export Coefficient Model (ECM). The coupled model performed satisfactory for both hydrological and water quality variables (Nash-Sutcliffe efficiency >0.5). Our modelling practice revealed that polder, non-polder, and mountainous areas had P load of 211.4, 437.2, and 149.9 t yr-1, respectively. P load intensity in lowlands and mountains was 1.75 and 0.60 kg ha-1 yr-1, respectively. A higher P load intensity (>3 kg ha-1 yr-1) was mainly observed in the non-polder area. In lowland areas, irrigated cropland, aquaculture ponds and impervious surfaces contributed 36.7%, 24.8%, and 25.8% of the P load, respectively. In mountainous areas, irrigated croplands, aquaculture ponds, and impervious surfaces contributed 28.6%, 27.0%, and 16.4% of the P load, respectively. Rivers with relatively high P load risks were mainly observed around big cities during rice season, owing to a large contribution of P load from the non-point source pollution of urban and agricultural activities. This study demonstrated a raster-based estimation of watershed P load and their impacts on surrounding rivers using coupled process-based models. It would be useful to identify the hotspots and hot moments of P load at the grid scale.


Asunto(s)
Monitoreo del Ambiente , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/análisis , Ecosistema , Fósforo/análisis , Ríos
17.
Angew Chem Int Ed Engl ; 62(7): e202216326, 2023 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-36519523

RESUMEN

Single-atom catalysts offer a promising pathway for electrochemical CO2 conversion. However, it is still a challenge to optimize the electrochemical performance of dual-atom catalysts. Here, an atomic indium-nickel dual-sites catalyst bridged by an axial oxygen atom (O-In-N6 -Ni moiety) was anchored on nitrogenated carbon (InNi DS/NC). InNi DS/NC exhibits superior CO selectivity with Faradaic efficiency higher than 90 % over a wide potential range from -0.5 to -0.8 V versus reversible hydrogen electrode (vs. RHE). Moreover, an industrial CO partial current density up to 317.2 mA cm-2 is achieved at -1.0 V vs. RHE in a flow cell. In situ ATR-SEIRAS combined with theory calculations reveal that the synergistic effect of In-Ni dual-sites and O atom bridge not only reduces the reaction barrier for the formation of *COOH, but also retards the undesired hydrogen evolution reaction. This work provides a feasible strategy to construct dual-site catalysts towards energy conversion.

18.
Angew Chem Int Ed Engl ; 62(32): e202306420, 2023 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-37264717

RESUMEN

Sluggish oxygen evolution kinetics and serious charge recombination restrict the development of photoelectrochemical (PEC) water splitting. The advancement of novel metal-organic frameworks (MOFs) catalysts bears practical significance for improving PEC water splitting performance. Herein, a MOF glass catalyst through melting glass-forming cobalt-based zeolitic imidazolate framework (Co-ag ZIF-62) was introduced on various metal oxide (MO: Fe2 O3 , WO3 and BiVO4 ) semiconductor substrates coupled with NiO hole transport layer, constructing the integrated Co-ag ZIF-62/NiO/MO photoanodes. Owing to the excellent conductivity, stability and open active sites of MOF glass, Co-ag ZIF-62/NiO/MO photoanodes exhibit a significantly enhanced photoelectrochemical water oxidation activity and stability in comparison to pristine MO photoanodes. From experimental analyses and density functional theory calculations, Co-ag ZIF-62 can effectively promote charge transfer and separation, improve carrier mobility, accelerate the kinetics of oxygen evolution reaction (OER), and thus improve PEC performance. This MOF glass not only serves as an excellent OER cocatalyst on tunable photoelectrodes, but also enables promising opportunities for PEC devices for solar energy conversion.

19.
Small ; 18(2): e2105130, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34862720

RESUMEN

Edge termination plays a vital role in determining the properties of 2D materials. By performing compelling ab initio simulations, a lowest-energy U-edge [ZZ(U)] reconstruction is revealed in the bilayer phosphorene. Such reconstruction reduces 60% edge energy compared with the pristine one and occurs almost without an energy barrier, implying it should be the dominating edge in reality. The electronic band structure of phosphorene nanoribbon with such reconstruction resembles that of an intrinsic 2D layer, exhibiting nearly edgeless band characteristics. Although ZZ(U) changes the topology of phosphorene nanoribbons, simulated transmission electron microscope, scanning transmission electron microscope and scanning tunneling microscope images indicate it is very hard to be identified. One possible identified method is infrared/Raman analyses because the ZZ(U) edge alters vibrational modes dramatically. In addition, it also increases the thermal conductivity of PNR 1.4 and 2.3 times than the pristine and Klein edges.

20.
Small ; 18(40): e2203274, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36050882

RESUMEN

The design and synthesis of novel two-dimensional (2D) materials that possess robust structural stability and unusual physical properties may open up enormous opportunities for device and engineering applications. Herein, a 2D sumanene lattice that can be regarded as a derivative of the conventional Kagome lattice is proposed. The tight-binding analysis demonstrates sumanene lattice contains two sets of Dirac cones and two sets of flat bands near the Fermi surface, distinctively different from the Kagome lattice. Using first-principles calculations, two possible routines for the realization of stable 2D sumanene monolayers (named α phase and ß phase) are theoretically suggested, and an α-sumanene monolayer can be experimentally synthesized with chemical vapor deposition using C21 H12 as a precursor. Small binding energies on Au(111) surface (e.g., -37.86 eV Å-2 for α phase) signify the possibility of their peel-off after growing on the noble metal substrate. Importantly, the GW plus Bethe-Salpeter equation calculations demonstrate both monolayers have moderate band gaps (1.94 eV for α) and ultrahigh carrier mobilities (3.4 × 104 cm2  V-1  s-1 for α). In particular, the α-sumanene monolayer possesses a strong exciton binding energy of 0.73 eV, suggesting potential applications in optics.

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