57 research outputs found

    Outstanding hydrogen evolution reaction catalyzed by porous nickel diselenide electrocatalysts

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    To relieve our strong reliance on fossil fuels and to reduce greenhouse effects, there is an ever-growing interest in using electrocatalytic water splitting to produce green, renewable, and environment-benign hydrogen fuel via the hydrogen evolution reaction. For commercially feasible water electrolysis, it is imperative to develop electrocatalysts that perform as efficiently as Pt but using only earth-abundant commercial materials. However, the highest performance current catalysts consist of nanostructures made by using complex methods. Here we report a porous nickel diselenide (NiSe_2) catalyst that is superior for water electrolysis, exhibiting much better catalytic performance than most first-row transition metal dichalcogenide-based catalysts, well-studied MoS_2, and WS_2-based catalysts. Indeed NiSe2 performs comparably to the state-of-the-art Pt catalysts. We fabricate NiSe_2 directly from commercial nickel foam by acetic acid-assisted surface roughness engineering. To understand the origin of the high performance, we use first-principles calculations to identify the active sites. This work demonstrates the commercial possibility of hydrogen production via water electrolysis using porous bulk NiSe_2 catalysts

    Cultivation of the microalga, Chlorella pyrenoidosa, in biogas wastewater

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    Biogas wastewater is always a problem as a result of its extremely high concentrations of nitrogen and phosphorus, which is the main reason for the eutrophication of the surrounding water. The microalga, Chlorella pyrenoidosa, can utilize the nitrogen and phosphorus in wastewater for its growth. Therefore, the microalga was introduced to be cultivated in the biogas wastewater, which could not only bioremediate the wastewater, but also produce plenty of the microalga biomass that could be used for the exploitation of fertilizers, feed additives and biofuels. This study showed that the microalga, C. pyrenoidosa could grow well in the biogas wastewater under optimal condition: initial cell density of 0.15 (OD(680)), pH 8 and illumination intensity of 10000 LX. Under the optimal condition, the dry cell weight of the microalgae reached 0.1 g/L after cultivation in the wastewater for fourteen (14) days; in the meantime, the microalga also removed 71.8% of phosphorus, 100% of ammoniacal nitrogen (NH(4)(+)-N), 52.8% of nitrate nitrogen (NO(3)-N) and 23.0% of nitrite nitrogen (NO(2)-N) from the biogas wastewater, suggesting that the cultivation of C. pyrenoidosa in biogas wastewater would be efficient for the treatment of wastewater. This study also provided a low-cost way to produce the microalga and its relevant products.Key Scientific and Technological Project of Fujian Province[2010Y0039]; Spark Project of Fujian Province[2010S0068]; Foundation for Innovative Research Team of Jimei University, China[2010A004

    Atomic H-Induced Mo_2C Hybrid as an Active and Stable Bifunctional Electrocatalyst

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    Mo_2C nanocrystals (NCs) anchored on vertically aligned graphene nanoribbons (VA-GNR) as hybrid nanocatalysts (Mo_2C-GNR) are synthesized through the direct carbonization of metallic Mo with atomic H treatment. The growth mechanism of Mo2C NCs with atomic H treatment is discussed. The Mo_2C-GNR hybrid exhibits highly active and durable electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). For HER, in an acidic solution the Mo_2C-GNR has an onset potential of 39 mV and a Tafel slope of 65 mV dec^(-1), in a basic solution Mo_2C-GNR has an onset potential of 53 mV, and Tafel slope of 54 mV dec^(-1). It is stable in both acidic and basic media. Mo2C-GNR is a high activity ORR catalyst with a high peak current density of 2.01 mA cm^(-2), an onset potential of 0.94 V that is more positive vs reversible hydrogen electrode, a high electron transfer number n (∼3.86) and long-term stability

    Atomic H-Induced Mo_2C Hybrid as an Active and Stable Bifunctional Electrocatalyst

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    Mo_2C nanocrystals (NCs) anchored on vertically aligned graphene nanoribbons (VA-GNR) as hybrid nanocatalysts (Mo_2C-GNR) are synthesized through the direct carbonization of metallic Mo with atomic H treatment. The growth mechanism of Mo2C NCs with atomic H treatment is discussed. The Mo_2C-GNR hybrid exhibits highly active and durable electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). For HER, in an acidic solution the Mo_2C-GNR has an onset potential of 39 mV and a Tafel slope of 65 mV dec^(-1), in a basic solution Mo_2C-GNR has an onset potential of 53 mV, and Tafel slope of 54 mV dec^(-1). It is stable in both acidic and basic media. Mo2C-GNR is a high activity ORR catalyst with a high peak current density of 2.01 mA cm^(-2), an onset potential of 0.94 V that is more positive vs reversible hydrogen electrode, a high electron transfer number n (∼3.86) and long-term stability

    Graphene and Beyond: Recent Advances in Two-Dimensional Materials Synthesis, Properties, and Devices

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    Since the isolation of graphene in 2004, two-dimensional (2D) materials research has rapidly evolved into an entire subdiscipline in the physical sciences with a wide range of emergent applications. The unique 2D structure offers an open canvas to tailor and functionalize 2D materials through layer number, defects, morphology, moir\ue9 pattern, strain, and other control knobs. Through this review, we aim to highlight the most recent discoveries in the following topics: theory-guided synthesis for enhanced control of 2D morphologies, quality, yield, as well as insights toward novel 2D materials; defect engineering to control and understand the role of various defects, including in situ and ex situ methods; and properties and applications that are related to moir\ue9 engineering, strain engineering, and artificial intelligence. Finally, we also provide our perspective on the challenges and opportunities in this fascinating field

    PLOS ONE by Dr Zhou.zip

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    fMRI DATA of ASD and the healthy controa

    Synthesis and biomedical applications of phthalocyanine complexes

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    Because of its large conjugated system,phthalocyanine complexes have been widely used in catalysis,photoelectric conversion,and biomedicine.Phthalocyanine complexes can be synthesized by many methods such as coordination insertion method,direct substitution method,and template reaction method.The applications of phthalocyanine complexes have been reported in tumor diagnosis and treatment mainly including photoacoustic imaging (PAI),magnetic resonance imaging (MRI),photodynamic therapy (PDT),and photo thermal therapy (PTT).Here,the recent advances in synthesis and biomedical applications of phthalocyannine complexes were reviewed

    Functional Connectivity of the Caudal Anterior Cingulate Cortex Is Decreased in Autism.

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    The anterior cingulate cortex (ACC) is frequently reported to have functionally distinct sub-regions that play key roles in different intrinsic networks. However, the contribution of the ACC, which is connected to several cortical areas and the limbic system, to autism is not clearly understood, although it may be involved in dysfunctions across several distinct but related functional domains. By comparing resting-state fMRI data from persons with autism and healthy controls, we sought to identify the abnormalities in the functional connectivity (FC) of ACC sub-regions in autism. The analyses found autism-related reductions in FC between the left caudal ACC and the right rolandic operculum, insula, postcentral gyrus, superior temporal gyrus, and the middle temporal gyrus. The FC (z-scores) between the left caudal ACC and the right insula was negatively correlated with the Stereotyped Behaviors and Restricted Interests scores of the autism group. These findings suggest that the caudal ACC is recruited selectively in the pathomechanism of autism

    Water Caltrop (<i>Trapa quadrispinosa</i> Roxb.) Husk Improves Oxidative Stress and Postprandial Blood Glucose in Diabetes: Phenolic Profiles, Antioxidant Activities and α-Glycosidase Inhibition of Different Fractions with In Vitro and In Silico Analyses

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    The aim of this study was to investigate the phenolic profiles, antioxidant activities and α-glycosidase inhibitory activities of three different phenolic fractions from water caltrop (Trapa quadrispinosa Roxb.) husk and to further explore the predominant compounds and their mechanisms on α-glycosidase inhibition by virtual screening and molecular dynamics. A total of 29 substances were identified and quantified in this study. Tannins were the main constituents of water caltrop husk extract. All of the free phenolic (FP), esterified phenolic (EP) and insoluble-bound phenolic (BP) fractions exhibited good antioxidant activities, and the BP had the highest radical scavenging ability with IC50 values of 0.82 ± 0.12 μg/mL (ABTS) and 1.15 ± 0.02 μg/mL (DPPH), respectively (p 50 value of FP was 1.43 ± 0.12 μg/mL. The 1,2,6-trigalloylglucose and α-glycosidase complex had better root mean square deviations (RMSD) stability via molecular dynamics simulation study. Results obtained from this study may provide a good potential natural resource for the improvement of oxidative stress injury and blood glucose control in diabetes mellitus, which could expand the use of water caltrop husk and improve its economic value
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