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ACS Applied Materials & Interfaces Jun 2024Metal-semiconductor junctions play an important role in the development of electronic and optoelectronic devices. A Schottky junction photodetector based on...
Metal-semiconductor junctions play an important role in the development of electronic and optoelectronic devices. A Schottky junction photodetector based on two-dimensional (2D) materials is promising for self-powered photodetection with fast response speed and large signal-to-noise ratio. However, it usually suffers from an uncontrolled Schottky barrier due to the Fermi level pinning effect arising from the interface states. In this work, all-2D Schottky junctions with near-ideal Fermi level depinning are realized, attributed to the high-quality interface between 2D semimetals and semiconductors. We further demonstrate asymmetric diodes based on multilayer graphene/MoS/PtSe with a current rectification ratio exceeding 10 and an ideality factor of 1.2. Scanning photocurrent mapping shows that the photocurrent generation mechanism in the heterostructure switches from photovoltaic effect to photogating effect at varying drain biases, indicating both energy conversion and optical sensing are realized in a single device. In the photovoltaic mode, the photodetector is self-powered with a response time smaller than 100 μs under the illumination of a 405 nm laser. In the photogating mode, the photodetector exhibits a high responsivity up to 460 A/W originating from a high photogain. Finally, the photodetector is employed for single-pixel imaging, demonstrating its high-contrast photodetection ability. This work provides insight into the development of high-performance self-powered photodetectors based on 2D Schottky junctions.
PubMed: 38877995
DOI: 10.1021/acsami.4c04023 -
Environmental Geochemistry and Health Jun 2024High cadmium (Cd) concentrations widely occured in selenium (Se)-rich soils, which has been an important obstacle in the usage of Se-rich soils. There is still no...
High cadmium (Cd) concentrations widely occured in selenium (Se)-rich soils, which has been an important obstacle in the usage of Se-rich soils. There is still no special information detailing the enrichment process and mechanism of Cd in Se-rich soils. 4474 soils and 21 rocks in Lanshan District were sampled to detect its enrichment process. The surface soils have Cd concentrations of 0.01-9.41 mg·kg (an average of 0.16 mg·kg). The soil Cd concentrations were significantly correlated with soil Se concentrations. The relatively higher-Cd surface soils are distributed in Lower-middle Ordovician carbonate areas with Se-rich soils and Quaternary areas with typical anthropic activities. Surface soils in Ordovician carbonate area have the highest Cd concentrations. Soil Cd concentrations are significantly correlated with sulfophil elements (Zinc (Zn), Copper (Cu), Molybdenum (Mo), Lead (Pb) and Arsenic (As) etc.), Ca (Calcium) concentrations and soil organic carbon (SOC). The soil and rock samples from different geological units also confirmed soil Cd concentrations developing from Ordovician carbonates were higher than those from other rocks. The results indicate the soil Cd concentrations were the complex consequences of bedrock, soil-forming processes and anthropogenic activities. Higher Ca concentrations and more reduction environments result in high-Cd bedrock. CaCO leaching and alkaline pH, which are the special soil-forming process of carbonates, enrich Cd in soils. Agricultural and industrial activities also affect soil Cd concentrations. An enrichment model of Cd in Se-rich soils is forwarded.
Topics: China; Soil Pollutants; Cadmium; Soil; Selenium; Environmental Monitoring
PubMed: 38877343
DOI: 10.1007/s10653-024-02022-2 -
Environmental Pollution (Barking, Essex... Jun 2024Breast milk is a vital source of nutrition for breastfed infants, providing essential nutrients and elements but, in some cases, toxic ones. This is the first...
Breast milk is a vital source of nutrition for breastfed infants, providing essential nutrients and elements but, in some cases, toxic ones. This is the first case-control study that investigated the elemental profile of breast milk samples collected from mothers residing in Matiari (Sindh), a region with insufficient industrial waste management, and its potential impact on infants' anthropometrics. Precisely, 62 milk samples, including 42 cases and 20 controls, were analyzed using the ICP-MS technique. Overall, six elements showed significance between the two groups, arsenic (As) was present at 0.68 μg/L in cases and absent in controls, while lead (Pb) exhibited elevated concentrations in the case group at 4.56 μg/L compared to 0.25 μg/L in controls, well-known for their toxicity. Barium (Ba) and manganese (Mn) levels were also higher in cases, associated with reported health effects on child well-being. Essential elements molybdenum (Mo) and selenium (Se) were higher in the controls. Furthermore, the association of these metals with the child growth standards as per WHO guidelines was calculated. Linear regression analysis revealed As negatively associated with WAZ and WHZ scores, while Mo was positively associated with WAZ, WHZ, and HAZ scores. These findings highlight serious health concerns in the region, where toxic elements pervade drinking water and food sources. Immediate actions are imperative to maintain the wellness of future generations.
PubMed: 38876378
DOI: 10.1016/j.envpol.2024.124368 -
Environmental Science & Technology Jul 2024Polyamide (PA)-based nanofiltration (NF) membranes have demonstrated extensive applications for a sustainable water-energy-environment nexus. A rational control of...
Polyamide (PA)-based nanofiltration (NF) membranes have demonstrated extensive applications for a sustainable water-energy-environment nexus. A rational control of interfacial polymerization (IP) is highly efficacious to enhance NF separation performance yet remains a technical challenge. Herein, we proposed a regulation strategy of constructing amphiphilic molybdenum disulfide/cetyltrimethylammonium bromide interlayer atop the Kevlar hydrogel substrate. The amphiphilic nanosheet interlayered NF membrane exhibited a crumpled PA surface with an elevated cross-linking degree of 76.9%, leading to an excellent water permeance (16.8 L m h bar) and an impressive NaSO rejection (99.1%). Meanwhile, the selectivity coefficient of NaSO/NaCl of the optimized TFC membrane reached 91, surpassing those of the recently reported NF membranes. Moreover, the optimized membrane exhibited a desirable rejection of over 90% against Mn and Cu in actual textile wastewater. Importantly, the underlying NF membrane formation mechanism was elucidated via both experiments and molecular simulations. The synchronous control of mass and heat transfer of IP process offers a new methodology for the state-of-the-art membrane fabrication, which opens more avenues in softening of brackish water and purification of industrial wastewater containing heavy metal ions.
Topics: Membranes, Artificial; Water Purification; Polymerization; Nanostructures; Molybdenum
PubMed: 38875312
DOI: 10.1021/acs.est.4c04063 -
Langmuir : the ACS Journal of Surfaces... Jul 2024Plasmonic metal oxides are promising photocatalysts for the artificial photosynthesis of green ammonia due to localized surface plasmon resonance (LSPR) enhanced...
Plasmonic metal oxides are promising photocatalysts for the artificial photosynthesis of green ammonia due to localized surface plasmon resonance (LSPR) enhanced photoconversion and rich surface oxygen vacancies improved chemisorption and activation of dinitrogen molecules. However, these oxygen vacancies are unstable during the photocatalytic process and could be oxidized by photogenerated holes, leading to the vanishing of the LSPR. Here, we fabricated antimony-doped molybdenum trioxide nanosheets with stable plasmonic absorption extending into the near-infrared (NIR) range, even after harsh treatment in oxidative atmospheric conditions at high temperatures. For undoped plasmonic MoO nanosheets, the LSPR originates from the abundant oxygen vacancies that vanish after heat treatment at high temperatures in air, leading to the disappearance of the LSPR absorption. Sb doping does not significantly increase the concentration of oxygen vacancies while donating more free electrons because Sb can keep a lower oxidation state. Heat treatment diminished the oxygen vacancies while not affecting the low oxidation state of Sb. As a result, heat-treated Sb-doped MoO nanosheets still show strong LSPR absorption in the NIR range. Both experimental results and theoretical calculations demonstrated that add-on states close to the Fermi level are formed due to the Sb doping and high concentration of oxygen vacancies. The prepared samples were used for photocatalytic nitrogen reduction and showed an LSPR-dependent photocatalytic performance. The present work has provided an effective strategy to stabilize the LSPR of plasmonic semiconductor photocatalysts.
PubMed: 38875214
DOI: 10.1021/acs.langmuir.4c01135 -
Small Methods Jun 2024The two-dimensional (2-D) Janus and amphiphilic molybdenum disulfide (MoS) nanosheet with opposite optical activities on each side (amphichiral) is synthesized by...
The two-dimensional (2-D) Janus and amphiphilic molybdenum disulfide (MoS) nanosheet with opposite optical activities on each side (amphichiral) is synthesized by modifying sandwich-like bulk MoS with tannic acid and cholesterol through biphasic emulsion method. This new type of amphichiral Janus MoS nanosheet consists of a hydrophilic and positive optical activity tannic acid side as well as a hydrophobic and negative optical activity cholesterol side thereby characterized by circular dichroism. Surface-directed orientational differentiation assemblies are performed for the as-synthesized 2D material and are characterized by contact angle, infrared spectroscopy, X-ray photoelectron, and circular dichroism spectroscopies. The amphiphilic nature of the materials is demonstrated by the pre-organization of the nanosheets on either hydrophobic or hydrophilic surfaces, providing unprecedented properties of circular dichroism signal enhancement and wettability. Selective detachment of the surface organic groups (cholesterol and tannic acid fragments) is realized by matrix-assisted laser desorption/ionisation - time-of-flight (MALDI-TOF) mass spectrometry, and the dual substrate release in tissue is detected by ex vivo mass spectrometry imaging.
PubMed: 38874104
DOI: 10.1002/smtd.202400533 -
ACS Sensors Jun 2024The development of a portable, low-cost sensor capable of accurately detecting HS gas in exhaled human breath at room temperature is highly anticipated in the fields of...
The development of a portable, low-cost sensor capable of accurately detecting HS gas in exhaled human breath at room temperature is highly anticipated in the fields of human health assessment and food spoilage evaluation. However, achieving outstanding gas sensing performance and applicability for flexible room-temperature operation with parts per billion HS gas sensors still poses technical challenges. To address this issue, this study involves the in situ growth of MoS nanosheets on the surface of InO fibers to construct a p-n heterojunction. The InO@MoS-2 sensor exhibits a high response of 460.61 to 50 ppm of HS gas at room temperature, which is 19.5 times higher than that of the pure InO sensor and 322.1 times higher than that of pure MoS. The InO@MoS-2 also demonstrates a minimum detection limit of 3 ppb and maintains a stable response to HS gas even after being bent 50 times at a 60° angle. These exceptional gas sensing properties are attributed to the increase in oxygen vacancies and chemisorbed oxygen on InO@MoS-2 nanofibers as well as the formation of the p-n heterojunction, which modulates the heterojunction barrier. Furthermore, in this study, we successfully applied the InO@MoS-2 sensor for oral disease and detection of food spoilage conditions, thereby providing new design insights for the development of portable exhaled gas sensors and gas sensors for evaluating food spoilage conditions at room temperature.
Topics: Humans; Hydrogen Sulfide; Breath Tests; Molybdenum; Temperature; Limit of Detection; Disulfides; Indium; Sulfides
PubMed: 38872232
DOI: 10.1021/acssensors.4c00866 -
Exposure to iodine, essential and non-essential trace element through seaweed consumption in humans.Scientific Reports Jun 2024Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace...
Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace elements highlight the need for comprehensive studies on exposure associated with seaweed consumption. To address this gap in knowledge, we carried out a feeding intervention study of three common edible seaweeds (Nori, Kombu, and Wakame) in 11 volunteers, aiming to elucidate the extent of both beneficial and harmful trace element exposure through seaweed consumption in humans. Concentrations of total arsenic, cobalt, copper, cadmium, iodine, molybdenum, selenium, and zinc were measured in urine samples before and following seaweed consumption. Elements concentrations were also measured in the seaweeds provided for the study. Descriptive analysis for each element were conducted and we used quantile g-computation approach to assess the association between the 8-element mixture and seaweed consumption. Differences in urine element concentrations and seaweed consumption were analyzed using generalized estimating equations (GEE). Urinary concentrations of iodine and total arsenic increased after seaweed consumption. When we analyze the 8-element mixture, the largest weight was observed for iodine after Kombu consumption while for total arsenic was observed after Wakame consumption. Similar results were observed when we compared the mean differences between the elements before and after seaweed consumption through the GEE. Seaweed consumption relates with increased urinary iodine and total arsenic concentrations, particularly after Kombu and Wakame consumption.
Topics: Seaweed; Humans; Iodine; Trace Elements; Female; Male; Adult; Arsenic; Middle Aged; Selenium
PubMed: 38871780
DOI: 10.1038/s41598-024-64556-w -
Proceedings of the National Academy of... Jun 2024Biofilm formation and surface attachment in multiple Alphaproteobacteria is driven by unipolar polysaccharide (UPP) adhesins. The pathogen produces a UPP adhesin, which...
Biofilm formation and surface attachment in multiple Alphaproteobacteria is driven by unipolar polysaccharide (UPP) adhesins. The pathogen produces a UPP adhesin, which is regulated by the intracellular second messenger cyclic diguanylate monophosphate (c-di-GMP). Prior studies revealed that DcpA, a diguanylate cyclase-phosphodiesterase, is crucial in control of UPP production and surface attachment. DcpA is regulated by PruR, a protein with distant similarity to enzymatic domains known to coordinate the molybdopterin cofactor (MoCo). Pterins are bicyclic nitrogen-rich compounds, several of which are produced via a nonessential branch of the folate biosynthesis pathway, distinct from MoCo. The pterin-binding protein PruR controls DcpA activity, fostering c-di-GMP breakdown and dampening its synthesis. Pterins are excreted, and we report here that PruR associates with these metabolites in the periplasm, promoting interaction with the DcpA periplasmic domain. The pteridine reductase PruA, which reduces specific dihydro-pterin molecules to their tetrahydro forms, imparts control over DcpA activity through PruR. Tetrahydromonapterin preferentially associates with PruR relative to other related pterins, and the PruR-DcpA interaction is decreased in a mutant. PruR and DcpA are encoded in an operon with wide conservation among diverse Proteobacteria including mammalian pathogens. Crystal structures reveal that PruR and several orthologs adopt a conserved fold, with a pterin-specific binding cleft that coordinates the bicyclic pterin ring. These findings define a pterin-responsive regulatory mechanism that controls biofilm formation and related c-di-GMP-dependent phenotypes in and potentially acts more widely in multiple proteobacterial lineages.
Topics: Biofilms; Agrobacterium tumefaciens; Pterins; Cyclic GMP; Bacterial Proteins; Proteobacteria; Molybdenum Cofactors; Periplasm; Periplasmic Proteins; Periplasmic Binding Proteins; Gene Expression Regulation, Bacterial
PubMed: 38870058
DOI: 10.1073/pnas.2319903121 -
Nanomaterials (Basel, Switzerland) Jun 2024Atomically thin two-dimensional transition metal dichalcogenides (TMDCs) have been regarded as ideal and promising nanomaterials that bring broad application prospects... (Review)
Review
Atomically thin two-dimensional transition metal dichalcogenides (TMDCs) have been regarded as ideal and promising nanomaterials that bring broad application prospects in extensive fields due to their ultrathin layered structure, unique electronic band structure, and multiple spatial phase configurations. TMDCs with different phase structures exhibit great diversities in physical and chemical properties. By regulating the phase structure, their properties would be modified to broaden the application fields. In this mini review, focusing on the most widely concerned molybdenum dichalcogenides (MoX: X = S, Se, Te), we summarized their phase structures and corresponding electronic properties. Particularly, the mechanisms of phase transformation are explained, and the common methods of phase regulation or phase stabilization strategies are systematically reviewed and discussed. We hope the review could provide guidance for the phase regulation of molybdenum dichalcogenides nanomaterials, and further promote their real industrial applications.
PubMed: 38869609
DOI: 10.3390/nano14110984