In this work, we report for the first time a plasmonic photoanode by decorating Au nanoparticles (NPs) onto two-dimensional (2D) Co3O4 nanosheets (NSs)/one-dimensional (1D) TiO2 nanorod arrays (NRAs) ...(Au/Co3O4/TiO2-NRAs) for enhanced visible-light photoelectrochemical (PEC) water splitting. In this plasmonic photoanode, TiO2 NRAs act as an electron acceptor, plasmonic Au NPs and hierarchical Co3O4 NSs serve as visible-light harvesters. Light absorption shows that Au/Co3O4/TiO2-NRAs heterojunction architectures exhibit greatly improved ability to harvest visible light due to the surface plasmon resonance (SPR) absorption of Au NPs and visible light harvesting ability of Co3O4 NSs. Spectroscopic measurements demonstrate that a type II band alignment is formed between Co3O4 and TiO2. Benefiting from the SPR effect, type II band alignment and novel hierarchical architecture, plasmonic Au/Co3O4/TiO2-NRAs photoanode shows remarkably enhanced visible-light PEC water splitting activity compared with Co3O4/TiO2-NRAs and pristine TiO2-NRAs photoanodes. Photocurrent density achieved by plasmonic photoanode is 37 and 1.2 times higher than those of TiO2-NRAs and Co3O4/TiO2-NRAs photoanodes, respectively. This work provides a promising strategy to highly enhance visible-light PEC water splitting activity of wide band-gap semiconductor-based photoelectrode materials.
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•Plasmonic photoanode of Au/Co3O4/TiO2 NRAs was fabricated for the first time.•Au/Co3O4/TiO2 NRAs were used as an efficient photoanode for PEC water splitting.•Au/Co3O4/TiO2 NRAs show enhanced visible light PEC water splitting activity.•Enhanced PEC activity is attributed to a type II band alignment and SPR effect.
•TiO2 NWAs decorated with Au NPs were fabricated by a facile chemical method.•TiO2/Au hybrid NWAs were used a sensor to detect Raman signals of R6 G molecules.•TiO2/Au NWAs show the highly sensitive ...and recyclable SERS activity.•The highly sensitive SERS of NWAs is ascribed to the charge transfer process.
We apply a facile photoreduction deposition strategy to grow Au nanoparticles (NPs) on the surfaces of TiO2 nanowire arrays (TiO2/Au NWAs) as a Raman sensitive substrate. The fabricated TiO2/Au NWAs can be used as a highly sensitive and recyclable SERS sensor for detecting the rhodamine 6 G (R6 G) molecules with a concentration as low as 10−9 M. Moreover, when irradiated with UV light, the SERS sensor with high sensitivity can be fully reproduced due to the superior self-cleaning capability of the substrate. By a comparative study on the SERS activities of R6 G molecules over the substrates of pure TiO2 NWAs, pure Au NPs and TiO2/Au NWAs, as well as the photoresponse performance of pure TiO2 and TiO2/Au NWAs under visible light illumination, we provide an illuminating insight into enhanced mechanism of SERS activity for TiO2/Au NWAs. The photoresponse performances and SERS activities provide experimental evidence that enhanced SERS activity of TiO2/Au NWAs is ascribed to the efficient charge transfer among Au, TiO2 and R6 G. This work throws a new light on enhanced mechanism for SERS activity of semiconductor/noble-metal substrates, which are expected to find potential applications to fabricate highly sensitive SERS sensors for the detection of analytes.
Self-organized and ordered CoFe2O4 nanotube arrays were prepared in porous anodic aluminum oxide template using an improved sol–gel approach. The attraction between the negatively charged sol ...particles and the positively charged pore wall of AAO is the causation of tube formation process. The morphology was studied by transmission electron and high-resolution field emission scanning electron microscope. A polycrystalline phase of the nanotube was found by X-ray and select area electron diffraction. Magnetic measurements showed that the magnetic orientation was weak in the arrays of nanotube, and the reason has been discussed.
Interindividual variability is important in the evolution of adaptative profiles of children with ASD having benefited from an early intervention make up for deficits in communication, language and ...social interactions. Therefore, this paper aimed to determine the nature of factors influencing the efficacy variability of a particular intervention technique i.e., "Play-based communication and behavior intervention" (PCBI).
The participants comprised 70 13-30-month-old toddlers with ASD enrolled in PCBI for 12 weeks. The Autism Treatment Evaluation Checklist (ATEC) was used to evaluate the efficacy of PCBI. Video recordings of 5 min of free-play before and after PCBI were used to examine behaviors of mothers and children and parent-child dyadic synchrony. Hierarchical multiple regression analyses and machine learning algorithms were performed to explore the effect of these potential predictors (mothers' factors, children's factors and videotaped mother-child interaction) of intervention efficacy.
The hierarchical regression analysis and the machine learning algorithms indicated that parenting stress, level of completion of training at home and mother-child dyadic synchrony were crucial factors in predicting and monitoring the efficacy of PCBI.
In summary, the findings suggest that PCBI could be particularly beneficial to children with ASD who show a good performance in the mother-child dyadic synchrony evaluation. A better dyadic mother-child synchrony could enhance the PCBI efficacy through adapted emotional and behavioral responses of the mother and the child and has a beneficial influence on the child's psychological development.
Hexagonal bismuth telluride (Bi2Te3) nanoplates and nanorings were synthesized by a simple solvothermal process. The composition, morphology and size of the as-prepared products were investigated by ...X-ray diffraction and transmission electron microscopy in detail. The systemically experiments have been performed to investigate the effect of alkaline additive NaOH on composition and morphology of Bi2Te3 nanostructures. The results indicate that alkaline additive NaOH is not necessary for the formation of Bi2Te3 nanostructures in a solvothermal process. However, NaOH plays an important role in determining the morphology and size of Bi2Te3 nanostructures. When the experiment was carried out with NaOH concentration ranging from 5 to 7M, hexagonal Bi2Te3 nanoplates with edge length of 140-280nm were synthesized. When the experiment was carried out at higher NaOH concentration of 9-11M, hexagonal Bi2Te3 nanorings were fabricated by dissolving the inner part of the hexagonal nanoplates with NaOH for the first time. A possible formation mechanism has been proposed based on the experimental results and analysis. This work may open a new rational route for the synthesis of hexagonal Bi2Te3 nanorings which may have some scientific and technological applications in various functional devices.
Although autism spectrum disorder (ASD) can currently be diagnosed at the age of 2 years, age at ASD diagnosis is still 40 months or even later. In order to early screening for ASD with more ...objective method, behavioral videos were used in a number of studies in recent years.
The still-face paradigm (SFP) was adopted to measure the frequency and duration of non-social smiling, protest behavior, eye contact, social smiling, and active social engagement in high-risk ASD group (HR) and typical development group (TD) (HR:
= 45; TD:
= 43). The HR group was follow-up until they were 2 years old to confirm final diagnosis. Machine learning methods were used to establish models for early screening of ASD.
During the face-to-face interaction (FF) episode of the SFP, there were statistically significant differences in the duration and frequency of eye contact, social smiling, and active social engagement between the two groups. During the still-face (SF) episode, there were statistically significant differences in the duration and frequency of eye contact and active social engagement between the two groups. The 45 children in the HR group were reclassified into two groups after follow-up: five children in the N-ASD group who were not meet the criterion of ASD and 40 children in the ASD group. The results showed that the accuracy of Support Vector Machine (SVM) classification was 83.35% for the SF episode.
The use of the social behavior indicator of the SFP for a child with HR before 2 years old can effectively predict the clinical diagnosis of the child at the age of 2 years. The screening model constructed using SVM based on the SF episode of the SFP was the best. This also proves that the SFP has certain value in high-risk autism spectrum disorder screening. In addition, because of its convenient, it can provide a self-screening mode for use at home.
Chinese Clinical Trial Registry, ChiCTR-OPC-17011995.
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•2D/2D g-C3N4/In2S3 heterostructures are explored for photocatalytic H2O2 production.•Light-driven H2O2 production in ultrapure water under organic electron donor free.•In2S3 is ...identified as a new promising material for photocatalytic H2O2 production.•2D/2D g-C3N4/In2S3 heterostructures shows remarkably enhanced H2O2 production.•The substantially augmented H2O2 production is unveiled by charge flow tracking.
Understanding the charge flow direction within semiconductor heterojunction is of crucial importance for designing and constructing next generation photocatalysts for fundamental perspective as well as efficient production of fuels such as hydrogen and hydrogen peroxide (H2O2). Here, two-dimensional (2D)/2D g-C3N4/In2S3 heterostructures are explored for photocatalytic H2O2 production in organic electron donor-free condition for the first time. The substantially augmented photocatalytic performance is unveiled by charge flow tracking realized through in situ reduction of Au ions by electron into Au and oxidation of Pb ions by hole into PbO2, revealing that photoinduced electrons of g-C3N4 move to In2S3 and holes remain in g-C3N4, prompting effective separation of charges. The experiments of radical trapping confirm that the photoexcited electrons accumulated on the conduction band of In2S3 in g-C3N4/In2S3 heterostructures generate H2O2 through a two-step one-electron reduction reaction of O2. This work not only identifies In2S3 as a new promising material for the photocatalytic H2O2 production but also provides a new approach for rational design of heterojunction photocatalyst via tracking charge flow direction to boost H2O2 production.
•Au nanoparticle-decorated hierarchical TiO2/Bi2WO6 nanorod arrays were fabricated.•Spectroscopic tests give evidence for the formation of a type II band alignment.•The photocatalyst exhibits ...remarkable visible-light PEC water splitting activity.•The photocatalyst shows enhanced visible-light photocatalytic degradation of MB.•Type II band alignment and SPR effect contribute to enhanced performance.
In this study, we show that the poor visible light photoelectrochemical (PEC) and photocatalytic activities of both wide-bandgap TiO2 and small-bandgap Bi2WO6 photocatalysts can be remarkably enhanced by constructing hierarchical Bi2WO6 nanosheet-wrapped TiO2 nanorod arrays (NRAs). X-ray photoelectron spectroscopy (XPS) measurements give direct experimental evidence for the establishment of a type II band alignment, which realizes visible light PEC performance of heterogeneous architecture through the transfer of photoexcited electrons from Bi2WO6 to TiO2. Moreover, Au nanoparticles (NPs) grown on the hierarchical Bi2WO6 nanosheets of TiO2/Bi2WO6 NRAs drastically enhance visible light PEC and photocatalytic activity of heterogeneous architectures because of surface plasmon resonance (SPR) effect. Benefiting from the synergistic effect of the type II band alignment and SPR effect, the hierarchical TiO2/Bi2WO6/Au NRAs achieve a photocurrent density of 29 μA cm−2, 11 times higher than that of TiO2 NRAs and 2.6 times as high as that of hierarchical TiO2/Bi2WO6 NRAs at 1 V vs Ag/AgCl. The hierarchical TiO2/Bi2WO6/Au NRAs exhibit remarkable stability in 2 h of light illumination. Additionally, the hierarchical TiO2/Bi2WO6/Au architectures show a significantly enhanced photocatalytic degradation for methyl blue (MB) molecules with a photodegradation of 91.5%. The study sheds new light on constructing visible light photocatalyst by forming the type II band alignment and integrating SPR effect.
Arrays of Nd5Fe95 - xBx (17 < = x < = 28) nanowires were fabricated by electrodepositing in pores of anodic aluminum oxide (AAO) templates. Transmission electron microscope result shows that the ...nanowires are about 40 nm in diameter and the aspect ratio is approximately 75. Selected area electron diffraction and X-ray diffraction results indicate that the nanowires are amorphous in structure at concentration x = 25. Vibrating sample magnetometer was employed to study the magnetic properties of nanowire arrays at room temperature. Due to the shape anisotropy effect, the arrays of nanowires exhibit obviously uniaxial magnetic anisotropy and the easy magnetizing axis is parallel to the nanowires. The coercivity with the magnetic field along the nanowire arrays decreases with the increasing of the B content.
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In this study, three-dimensional (3D) hierarchical PbS/ZnO heterojunction microspheres were successfully fabricated by combining a facile hydrothermal method and an improved ...successive ionic-layer adsorption and reaction (SILAR). As an adsorbent for the first time, the adsorption activities for the methyl orange (MO) of the prepared 3D hierarchical PbS/ZnO heterojunction microspheres were investigated. By optimizing the loading of PbS nanoparticles (NPs), the 3D hierarchical PbS/ZnO heterojunction microspheres show enhanced adsorption ability for MO with a high removal rate of more than 91% and a maximum adsorption capacity of 159 mg g−1 at equilibrium time within less than 40 min. The kinetics, thermodynamics, and isotherm investigations for the adsorption process of MO over the 3D hierarchical PbS/ZnO heterojunction microspheres experimentally demonstrate that the adsorption process follows a pseudo-second-order model with the nature of spontaneous and endothermic and is well fitted with the normal Langmuir isotherm model. Based on the comparative investigations and the experimental results of kinetics, thermodynamics, and isotherm studies, a reasonable adsorption mechanism of MO over the 3D hierarchical PbS/ZnO heterojunction microspheres was proposed. This work not only describes a new semiconductor heterojunction adsorbent but also offers a new idea for the fabrication of other semiconductor heterojunction adsorbents.
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