Strain in layered transition‐metal dichalcogenides (TMDs) is a type of effective approach to enhance the catalytic performance by activating their inert basal plane. However, compared with ...traditional uniaxial strain, the influence of biaxial strain and the TMD layer number on the local electronic configuration remains unexplored. Herein, via a new in situ self‐vulcanization strategy, biaxially strained MoS2 nanoshells in the form of a single‐crystalline Ni3S2@MoS2 core–shell heterostructure are realized, where the MoS2 layer is precisely controlled between the 1 and 5 layers. In particular, an electrode with the bilayer MoS2 nanoshells shows a remarkable hydrogen evolution reaction activity with a small overpotential of 78.1 mV at 10 mA cm‐2, and negligible activity degradation after durability testing. Density functional theory calculations reveal the contribution of the optimized biaxial strain together with the induced sulfur vacancies and identify the origin of superior catalytic sites in these biaxially strained MoS2 nanoshells. This work highlights the importance of the atomic‐scale layer number and multiaxial strain in unlocking the potential of 2D TMD electrocatalysts.
The effect of biaxial strain and layer numbers of MoS2 nanoshells on the electrocatalytic activity is investigated in detail. Calculations reveal the superiority of biaxial strain over uniaxial strain and identify the ideal Mo coordination and S vacancies for maximal catalytic activity.
Strain in layered transition-metal dichalcogenides (TMDs) is a type of effective approach to enhance the catalytic performance by activating their inert basal plane. However, compared with ...traditional uniaxial strain, the influence of biaxial strain and the TMD layer number on the local electronic configuration remains unexplored. Herein, via a new in situ self-vulcanization strategy, biaxially strained MoS
nanoshells in the form of a single-crystalline Ni
S
@MoS
core-shell heterostructure are realized, where the MoS
layer is precisely controlled between the 1 and 5 layers. In particular, an electrode with the bilayer MoS
nanoshells shows a remarkable hydrogen evolution reaction activity with a small overpotential of 78.1 mV at 10 mA cm
, and negligible activity degradation after durability testing. Density functional theory calculations reveal the contribution of the optimized biaxial strain together with the induced sulfur vacancies and identify the origin of superior catalytic sites in these biaxially strained MoS
nanoshells. This work highlights the importance of the atomic-scale layer number and multiaxial strain in unlocking the potential of 2D TMD electrocatalysts.
Oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are key reactions in diverse energy conversion devices, highlighting the importance of efficient catalysts. Edge‐anchored ...single atom catalysts (E‐SACs) emerge as a special class of atomic structure, but the detailed configuration and its correlation with catalytic activity remain little explored. Herein, a total of 78 E‐SACs (E‐TM‐Nx‐C) have been constructed based on 26 transition metal (TM) species with three coordination patterns. Using structural stability and ORR/OER catalytic activity as the evaluation criteria, a few catalytic structures comparable to Pt (111) for ORR and IrO2 (110) for OER are screened based on high‐throughput calculations. The screening results unveil that the E‐Rh‐N4‐C configuration exhibits most efficient bifunctional activity for both ORR and OER with an overpotential of 0.38 and 0.61 V, respectively. Electronic structure analysis confirms the distinctive edge effects on the electronic properties of TM and N species, and the feature importance derived from machine learning illustrates the efficacy of E‐TM‐Nx subunit configuration in determining the catalytic activity of E‐SACs. Finally, the trained Gradient Boosting Regression (GBR) model exhibits acceptable accuracy in predicting the OH intermediates adsorption strength for E‐SACs, thereby paving the way for expanding catalytic structures based on E‐SACs.
A data‐driven strategy is formulated to accelerate the discovery of Edge‐SACs by predicting the reactivity trends and structure‐activity relationships. A few outstanding E‐SACs structures on graphene for ORR and OER are screened out. It is shown that edge effects together with coordinated patterns govern their catalytic activity.
Fe–N–C catalysts are emerging as promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR), while they still suffer from sluggish reaction kinetics due to the discontented ...binding affinity between the Fe‐N4 sites and oxygen‐containing intermediates, and unsatisfactory stability. Herein, a flexible multichannel carbon fiber membrane immobilized with atomically dispersed Fe‐N4 sites and neighboring Fe nanoclusters/nanoparticles (FeN4‐FeNCP@MCF) is synthesized. The optimized geometric and electronic structures of the Fe atomic sites brought by adjacent Fe nanoclusters/nanoparticles and hierarchically porous structure of the carbon matrix endow FeN4‐FeNCP@MCF with outstanding ORR activity and stability, considerably outperforming its counterpart with FeN4 sites only and the commercial Pt/C catalyst. Liquid and solid‐state flexible zinc–air batteries employing FeN4‐FeNCP@MCF both exhibit outstanding durability. Theoretical calculation reveals that the Fe nanoclusters can trigger remarkable electron redistribution of the FeN4 sites and modulate the hybridization of central Fe 3d and O 2p orbitals, facilitating the activation of O2 molecules and optimizing the adsorption capacity of oxygen‐containing intermediates on FeN4 sites, and thus accelerating the ORR kinetic. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with nanoclusters/nanoparticles for efficient ORR catalysis.
In Fe7@FeN4 decorated multichannel carbon fibers, the Fe nanoclusters could effectively regulate the geometric and electronic structures of FeN4 active sites, which facilitate the activation of O2 molecules and enhance the absorption capacity of OOH, endowing the catalyst with superior ORR activity and stability as compared to its counterpart with FeN4 sites only and the Pt/C catalyst.
Abstract Fe–N–C catalysts are emerging as promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR), while they still suffer from sluggish reaction kinetics due to the ...discontented binding affinity between the Fe‐N 4 sites and oxygen‐containing intermediates, and unsatisfactory stability. Herein, a flexible multichannel carbon fiber membrane immobilized with atomically dispersed Fe‐N 4 sites and neighboring Fe nanoclusters/nanoparticles (FeN 4 ‐Fe NCP @MCF) is synthesized. The optimized geometric and electronic structures of the Fe atomic sites brought by adjacent Fe nanoclusters/nanoparticles and hierarchically porous structure of the carbon matrix endow FeN 4 ‐Fe NCP @MCF with outstanding ORR activity and stability, considerably outperforming its counterpart with FeN 4 sites only and the commercial Pt/C catalyst. Liquid and solid‐state flexible zinc–air batteries employing FeN 4 ‐Fe NCP @MCF both exhibit outstanding durability. Theoretical calculation reveals that the Fe nanoclusters can trigger remarkable electron redistribution of the FeN 4 sites and modulate the hybridization of central Fe 3 d and O 2 p orbitals, facilitating the activation of O 2 molecules and optimizing the adsorption capacity of oxygen‐containing intermediates on FeN 4 sites, and thus accelerating the ORR kinetic. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with nanoclusters/nanoparticles for efficient ORR catalysis.
It is important to tune the coordination configuration of dual‐atom catalyst (DAC), especially in the first coordination sphere, to render high intrinsic catalytic activities for oxygen ...reduction/evolution reactions (ORR/OER). Herein, a type of atomically dispersed and boron‐coordinated DAC structure, namely, FeN4B‐NiN4B dual sites, is reported. In this structure, the incorporation of boron into the first coordination sphere of FeN4/NiN4 atomic sites regulates its geometry and electronic structure by forming “Fe‐B‐N” and “Ni‐B‐N” bridges. The FeN4B‐NiN4B DAC exhibits much enhanced ORR and OER property compared to the FeN4‐NiN4 counterparts. Density functional theory calculations reveal that the boron‐induced charge transfer and asymmetric charge distributions of the central Fe/Ni atoms optimize the adsorption and desorption behavior of the ORR/OER intermediates and reduce the activation energy for the potential‐determining step. Zinc‐air batteries employing the FeN4B‐NiN4B cathode exhibit a high maximum power density (236.9 mW cm−2) and stable cyclability up to 1100 h. The result illustrates the pivotal role of the first‐coordination sphere of DACs in tuning the electrochemical energy conversion and storage activities.
Boron doping is introduced to the first coordination sphere of Fe and Ni atoms to induce the structural deformation and asymmetric charge distributions of FeN4B and NiN4B sites. The dual‐atom catalytic activities are remarkably enhanced compared to FeN4‐NiN4. Zinc–air batteries deliver a peak power density of 237 mW cm‐2 and long‐term cyclability up to 1100 h.
Two months after it was firstly reported, the novel coronavirus disease COVID-19 spread worldwide. However, the vast majority of reported infections until February occurred in China. To assess the ...effect of early travel restrictions adopted by the health authorities in China, we have implemented an epidemic metapopulation model that is fed with mobility data corresponding to 2019 and 2020. This allows to compare two radically different scenarios, one with no travel restrictions and another in which mobility is reduced by a travel ban. Our findings indicate that i) travel restrictions might be an effective measure in the short term, however, ii) they are ineffective when it comes to completely eliminate the disease. The latter is due to the impossibility of removing the risk of seeding the disease to other regions. Furthermore, our study highlights the importance of developing more realistic models of behavioral changes when a disease outbreak is unfolding.
DTL has been found to be related with multiple cancers. However, comprehensive analyses, which identify the prediction value of DTL in diagnosis, prognosis, immune infiltration and treatment, have ...rarely been reported so far.
Combined with the data online databases, the gene expression, gene mutation, function enrichment and the correlations with the immunity status and clinical indexes of DTL were analyzed. Expression of DTL and the degree of immune cell infiltration were examined by immunofluorescence (IF) and immunohistochemistry (IHC) and analyzed by statistical analysis. Furthermore, the influences of DTL on the cell cycle, cell proliferation and apoptosis were detected by live cell imaging, IF and flow cytometric (FC) analysis. Genomic stability assays were conducted by chromosome slide preparation.
DTL was widely expressed in various cells and tissues, while it was overexpressed in tumor tissues except acute myeloid leukemia (LAML). Pan-cancer bioinformatics analysis showed that the expression of DTL was correlated with the prognosis, immunotherapy, and clinical indexes in various cancers. In addition, gene set enrichment analysis (GSEA) uncovered that DTL was enriched in oocyte meiosis, pyrimidine metabolism, the cell cycle, the G2M checkpoint, mTORC1 signaling and E2F targets. Furthermore, the overexpression of DTL, and its association with immune cell infiltration and clinical indexes in liver hepatocellular carcinoma (LIHC), bladder urothelial carcinoma (BLCA) and stomach adenocarcinoma (STAD) were verified in our study. It was also verified that overexpression of DTL could regulate the cell cycle, promote cell proliferation and cause genomic instability in cultured cells, which may be the reason why DTL plays a role in the occurrence, progression and treatment of cancer.
Collectively, this study suggested that DTL is of clinical value in the diagnosis, prognosis and treatment of various cancers, and may be a potential biomarker in certain cancers.
Trigeminal neuralgia (TN) is a type of severe paroxysmal neuropathic pain commonly triggered by mild mechanical stimulation in the orofacial area. Piezo2, a mechanically gated ion channel that ...mediates tactile allodynia in neuropathic pain, can be potentiated by a cyclic adenosine monophosphate (cAMP)‐dependent signaling pathway that involves the exchange protein directly activated by cAMP 1 (Epac1). To study whether Piezo2‐mediated mechanotransduction contributes to peripheral sensitization in a rat model of TN after trigeminal nerve compression injury, the expression of Piezo2 and activation of cAMP signal‐related molecules in the trigeminal ganglion (TG) were detected. Changes in purinergic P2 receptors in the TG were also studied by RNA‐seq. The expression of Piezo2, cAMP, and Epac1 in the TG of the TN animals increased after chronic compression of the trigeminal nerve root (CCT) for 21 days, but Piezo2 knockdown by shRNA in the TG attenuated orofacial mechanical allodynia. Purinergic P2 receptors P2X4, P2X7, P2Y1, and P2Y2 were significantly up‐regulated after CCT injury. In vitro, Piezo2 expression in TG neurons was significantly increased by exogenous adenosine 5'‐triphosphate (ATP) and Ca2+ ionophore ionomycin. ATP pre‐treated TG neurons displayed elevated Ca2+i and faster increase in responding to blockage of Na+/Ca2+ exchanger by KB‐R7943. Furthermore, mechanical stimulation of cultured TG neurons led to sustained elevation in Ca2+i in ATP pre‐treated TG neurons, which is much less in naïve TG neurons, or is significantly reduced by Piezo2 inhibitor GsMTx4. These results indicated a pivotal role of Piezo2 in peripheral mechanical allodynia in the rat CCT model. Extracellular ATP, Ca2+ influx, and the cAMP‐to‐Epac1 signaling pathway synergistically contribute to the pathogenesis and the persistence of mechanical allodynia.
Chronic compression of the trigeminal nerve root (CCT) increases extracellular ATP level in trigeminal root entry zone (TREZ) and triggers Ca2+ influx into trigeminal ganglion (TG) neurons, stimulating Piezo2 expression along with the expression of multiple P2 receptors. ATP and its metabolite adenosine increase cAMP and exchange protein directly activated by cAMP 1 (Epac1) signaling, promoting the sensitization of Piezo2 channels. Ca2+‐stimulated Piezo2 expression and Piezo2‐mediated Ca2+ influx form a positive feedback loop, together with another likely positive feedback loop between ATP‐induced Ca2+ influx and Ca2+‐induced ATP release. These positive feedback loops supplemented with increasing receptor expression and elevating cAMP‐to‐Epac1 signaling, form a perfect storm inadvertently leads to the pathogenesis and the persistence of mechanical allodynia.
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