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In this study, we demonstrate for the first time the construction of a ternary BiVO4/FeVO4/Cu2O nanorod array (NRA) photoelectrode via seed-assisted refluxing, hydrothermal and successive ionic-layer adsorption and reaction (SILAR) method and its photoelectrochemical (PEC) water oxidation performance. The energy band structures of the BiVO4, FeVO4 and Cu2O show that two type-II band alignments with a ladder-like structure are formed in the constructed ternary BiVO4/FeVO4/Cu2O NRA photoelectrode, enabling the photoelectrode to display substantially enhanced PEC performance. The constructed ternary photoelectrode loaded with the optimized Cu2O nanoparticles achieves a zero-bias photocurrent density of 50 μA cm−2, 5 times higher than that of the pure BiVO4 NRA photoelectrode. The measurements of optical property reveal that the constructed BiVO4/FeVO4/Cu2O nanorod arrays (NRAs) demonstrate improved light absorption capability. The electrochemical impedance and photoluminescence measurements confirm that the charge carriers of the BiVO4/FeVO4/Cu2O heterojunction NRAs are transferred and separated effectively. The substantially boosted PEC water oxidation activity of the constructed ternary BiVO4/FeVO4/Cu2O heterojunction NRA photoelectrode is ascribed to the improved light harvesting and effective charge separation.

We report for the first time that nonmetal plasmonic TiN nanoparticles act as hot-electron booster to remarkably enhance photocurrent and hydrogen production of CdS nanoroad arrays (NRAs) via a photoelectrochemical cell. The optimized TiN–CdS NRAs produce a bias-free photocurrent of 2.9 mA cm−2. Furthermore, the highest photoconversion efficiency of the TiN–CdS nanorod array (NRA) photoanode with optimized loading of the TiN NPs is up to 2.2%, 1.6-fold that of the pristine CdS NRA photoanode (1.4%) at 0.22 V versus RHE. Most importantly, TiN–CdS NRAs achieve a hydrogen production rate of 101.5 μmol h−1 cm−2, about 2 times higher than that of the CdS NRAs. Experimental evidences of the photoluminescence emission apparently confirm that hot-electron injection from TiN to CdS plays a crucial role for enhancing photocurrent and hydrogen production. This work demonstrates that nonmetal plasmonic TiN can be integrated into new platforms for efficient solar energy conversion.

Herein, both plasmonic sensitizer and electron relay are integrated into ZnO/Au/CdS sandwich nanotube array (NTA) to construct a novel photoanode for efficient solar-to-hydrogen conversion via photoelectrochemical (PEC) cell. Under bias-free simulated solar light illumination, a photocurrent of the ZnO/Au/CdS sandwich NTA photoanode is up to 6.5 mA/cm2, 24 times that of ZnO, and 14 times that of ZnO/Au NTA photoanodes, respectively. Furthermore, the highest solar-to-hydrogen efficiency of the ZnO/Au/CdS sandwich NTA photoanode is 3.2% at 0.72 eV vs. RHE, 23 times as high as that of ZnO/Au and 80-folds that of the pure ZnO NTA photoanodes, respectively. The PEC and photoluminescence measurements experimentally demonstrate that the Aunanoparticles not only serve as plasmonic sensitizer to efficiently transfer the electrons from the defect level of ZnO to its conduction band via resonance coupling action of the plasmon and defect energy emission, but also serve as electron relay to transfer the electrons from the conduction band of CdS to that of ZnO, enabling the ZnO/Au/CdS sandwich NTAs to achieve greatly enhanced PEC water splitting activity. This work offers a new strategy for integrating both plasmonic sensitizer and electron relay into a photoanode for efficient conversion of solar energy to chemical energy.

Here, we first use a facile electrochemical deposition method to load Cu2O nanoparticles onto the BaTiO3 (BTO) surface to prepare BTO/Cu2O heterostructure photoanodes. Compared to the pure BTO photoanode, all BTO/Cu2O heterostructure photoanodes show outstanding visible light harvesting ability and greatly improved photoelectrochemical water splitting performance. By optimizing the loading amount of Cu2O nanoparticles, the photocurrent density achieved by BTO/Cu2O-100 photoanode is 0.26 mA/cm2 at 0 V versus Ag/AgCl, which is 2.6 times that of the bare BTO photoanode. In contrast with the photocurrent densities of the other reported BTO-based heterostructure photoanodes, the photocurrent density achieved by the present BTO/Cu2O-100 photoanode without bias voltage is much higher. Additionally, the maximum solar-to-hydrogen conversion efficiency of the BTO/Cu2O-100 heterostructure photoanode is 0.11% at 0.72 V versus reversible hydrogen electrode, approximately double that of BTO photoanode. The measurements of diffuse reflectance spectra, photoelectrochemical impedance and the room temperature photoluminescence spectra demonstrate that the improved photoelectrochemical performance contributes from the visible light absorption ability of Cu2O nanoparticles, efficient transport and separation of photogenerated electron-hole pairs, which are induced by the spontaneous polarization electric field of ferroelectric BTO, p-n junction and type-II band alignment of BTO/Cu2O heterostructure photoanode. A possible mechanism for the improved photoelectrochemical water splitting performance and charge transfer process is proposed.

ZnO/Cu2S nanotube arrays are fabricated firstly by a facile and capping-agent-free method, and the photo-electrochemical performance has been studied systematically. The results show that ZnO/Cu2S nanotube arrays achieve enhanced photo-electrochemical water splitting performance and the photocurrent densities of ZnO/Cu2S are 7.9 times than that of ZnO at 0 V versus Ag/AgCl. The performance of the ZnO/Cu2S nanotube arrays can be adjusted by changing the amount of Cu2S microcrystals. The results confirm that the enhanced photo-electrochemical performance of ZnO/Cu2S is due to the significantly improved visible light absorption, effective separation of photo-induced carriers due to the well band energy match and the formed p-n junction between ZnO and Cu2S.

Efficient removal of organic dyes from contaminated water has become a great challenge and urgent work due to increasingly serious environmental problems. Here, we have for the first time prepared nanolayer-constructed TiO(OH)

We report a Cu2O/CdS/ZnO photoanode constructed by coupling Cu2O and CdS nanoparticles on ZnO nanotube arrays (NTAs) via combining chemical bath deposition with successive ionic-layer adsorption an...

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.

ZnO nanotube arrays were synthesized by the electrodeposition method and Cu2O microcrystals with two kinds of morphologies were deposited on ZnO nanotube arrays successfully. At the deposition potential of −0.5 or −0.7 V, the cubic or spherical Cu2O microcrystals were selectively deposited on ZnO nanotube arrays. By adjusting the deposition time, Cu2O microcrystals with different sizes were obtained. The optical properties and photo-electrochemical performance of ZnO/Cu2O were measured. The results showed that the as-prepared ZnO/Cu2O heterojunction exhibited improved visible light absorption and enhanced photocurrent due to the excellent ability of Cu2O microcrystals for harvesting visible light, and the effective separation and transfer of photo-generated electrons and holes owing to p-n junction between ZnO and Cu2O. The experimental results demonstrate that the photo-electrochemical performance of ZnO/Cu2O heterojunction nanotube arrays can be manipulated by controlling the morphology and the size of Cu2O microcrystals.

Effective separation of charge carriers and substantial prolongation of charge carrier lifetime are two vital issues for a photoanode to achieve highly efficient photoelectrochemical (PEC) hydrogen generation. Herein, a Cu2O-nanoparticle-sensitized TiO2/CdS (TiO2/CdS/Cu2O) nanowire array photoanode is fabricated via subtly combining successive ionic layer adsorption and reaction with a chemical bath deposition method. Both the type-II band alignment with a stair-like structure and a p-n junction are integrated into this ternary photoanode. The fabricated photoanode shows a significant enhancement in the PEC H2 production with 4.3% efficiency. The measurements of light absorption, photoluminescence and electrochemical spectra undoubtedly demonstrate that the enhanced PEC H2 generation is ascribed to the remarkable enhancement of visible-light absorbing ability, efficient space charge separation and substantial prolongation of charge carrier lifetime, which are achieved by the synergetic effects of the type-II band alignment with a stair-like structure and the p-n junction. The enhanced PEC H2 generation demonstrates the potential of the TiO2/CdS/Cu2O nanowire arrays as a photoanode to efficiently convert solar energy into chemical fuels.

The hydrothermally prepared two-dimensional copper selenide nanosheets (2D CuSe NSs) have been employed for the first time to degrade rhodamine B (RhB) in the presence of hydrogen peroxide (H

This study provides insights into the charge transfer and solar light photocatalytic activity induced by the synergistic effect between defect state and plasmon in Au nanoparticle-decorated hierarchical 3D porous ZnO microspheres. Photoluminescence emission shows that the photogenerated electrons of ZnO are efficiently transferred from its defect level to the conduction band (CB) induced through the coupling action of the defect state and plasmon. Compared with the pure ZnO microsphere photocatalysts, the fabricated Au/ZnO microsphere photocatalysts show remarkably enhanced activity for the decomposition of methylene blue dyes under solar-light illumination. Moreover, the photocatalytic performance of the Au/ZnO microspheres was manipulated by tuning the size of the Au nanoparticles (NPs). When decorated with 10 nm Au NPs, the Au/ZnO microsphere photocatalyst achieves a rate constant of 0.09846 min−1, 26 and 8.5 times higher than those of the pure ZnO microsphere photocatalysts (0.00378 min−1) and the Au/ZnO microsphere photocatalysts decorated with 30 nm Au NPs (0.01154 min−1), respectively.. The enhanced photocatalytic performance of the Au/ZnO microsphere photocatalysts is ascribed to the defect state-plasmon coupling-induced efficient transfer of photogenerated electrons from the defect level to the CB of ZnO. This work enhances the understanding of the defect state-plasmon coupling-induced enhanced photocatalytic activity in metal/semiconductor heterostructure photocatalysts.

We have combined ferroelectric BaTiO3 nanostructures with α-Fe2O3 nanoparticles to prepare BaTiO3@α-Fe2O3 core@shell heterojunction photoelectrodes. The effects of α-Fe2O3 nanoparticle loadings on ...

The ZnO nanotube arrays were obtained by a simple three-step method, and then Au nanoparticles and Cu2O nanocrystals were decorated onto ZnO nanotube arrays successively. The composition, morphology, optical properties and photoelectrochemical performance of the as-prepared ZnO@Au@Cu2O nanotube arrays were characterized by X-ray diffraction, scanning electron microscopy, UV–vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, and photocurrent densities. The results confirmed that ZnO@Au@Cu2O nanotube arrays showed enhanced response to visible light and achieved an excellent photocurrent under visible light due to the localized surface plasmon resonance effect, visible light harvesting of Cu2O nanocrystals, effective transfer and separation of photo-generated charge carriers induced by p-n junction and well band energy match of the ZnO@Au@Cu2O nanotube arrays.

Efficient charge transfer and separation play a significant role in determining the photoelectrochemical (PEC) water-splitting performance of photocatalysts. Here, hierarchical nanowire arrays (NWAs) containing the TiO2 nanowire core and nickel-cobalt layered double hydroxide (NiCo-LDH) shell were synthesized by combining a hydrothermal method with a facile electrochemical-deposition process. The hierarchical structure not only forms heterojunctions between the TiO2 core and NiCo-LDH shell but also provides active sites for water-splitting reaction, achieving the charge transfer efficiency up to 87% and the charge separation efficiency up to 42% at 1.23 V vs. reversible hydrogen electrode (RHE) under one sun illumination. The excellent PEC water-splitting performance of TiO2@NiCo-LDH core-shell NWAs is attributed to the enhanced charge transfer and separation, resulting from the decoration of the NiCo-LDH cocatalyst. This facile and cost-effective strategy for integrating the light-harvesting TiO2 semiconductor and NiCo-LDH cocatalyst into a hierarchical core-shell nanostructure can be potentially applied in energy conversion and environmental applications.

The application of single-phase ZnO in hydrogen production through photoelectrochemical (PEC) water reduction is limited because of its unability to utilize photon energy of visible light and high carrier recombination rate. Herein, a three-dimensional (3D) plasmonic photoanode consisting of Au nanoparticles/ZnFe2O4 nanosheets coated onto ZnO nanotube arrays (Au/ZnFe2O4/ZnO NTAs) is rationally designed for hydrogen generation via PEC water splitting. The measurements preformed under simulated solar light and visible light irradiation show that the hot-electron injection of Au nanoparticles (NPs) significantly enhances PEC water splitting for hydrogen generation of 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode. Benefiting from the outstanding visible light harvesting ability of ZnFe2O4 nanosheets, efficient suppression of carrier recombination by a favorable band alignment, hot-electron injection of Au NPs and large surface area of 3D architecture, the 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode exhibits enhanced PEC water splitting for hydrogen generation. The hydrogen generation rate obtained by 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode is 1.5 and 5.7-fold of ZnO/ZnFe2O and ZnO NTAs photoanodes, respectively, at 0.6 V versus reference electrode (Ag/AgCl) under simulated solar light irradiation.

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.

Applications of single-phase TiO2 and ZnO in the field of photoelectrochemical (PEC) solar hydrogen generation are limited by their high recombination rate of photogenerated charge carriers. Herein, a novel three-dimensional (3D) architecture comprising two-dimensional (2D) ZnO nanosheets (NSs) coated onto one-dimensional (1D) TiO2 nanowire arrays (NWAs) (ZnO/TiO2 2D/1D NSs-NWAs) is designed as an efficient photoelectrode for PEC solar hydrogen production. A type II band alignment established in the photoanode enables the electrons to be efficiently transported from ZnO NSs to TiO2 NWAs and the holes to be transferred from TiO2 NWAs to ZnO NSs, efficiently suppressing the recombination of electrons and holes. Additionally, the 3D architecture offers large areas for harvesting light energy, large interfacial contact areas with the electrolyte, and more pathways for rapid transfer and separation of charge carriers. The ZnO/TiO2 2D/1D NS-NWA photoanode exhibits remarkable enhancement for hydrogen generation in a neutral electrolyte solution. The H2 generation rate of the ZnO/TiO2 2D/1D NS-NWA photoanode is 3-fold that of the bare TiO2 NWA photoanode. Moreover, the ZnO/TiO2 2D/1D NS-NWA photoanode shows excellent photostability after irradiation with light for 5 h.

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.

Effective separation of charge carriers and substantial prolongation of charge carrier lifetime are two vital issues for a photoanode to achieve highly efficient photoelectrochemical (PEC) hydrogen generation. Herein, a Cu

Background: 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. Method: 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: n = 45; TD: n = 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. Results: 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. Conclusion: 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. Trial registration: Chinese Clinical Trial Registry, ChiCTR-OPC-17011995.

In this study, we have developed a facile chemical bath deposition (CBD) method to grow p-type Cu2O nanoparticles on n-type TiO2 nanowire arrays (TiO2 NWAs) to fabricate TiO2/Cu2O core/shell heterojunction nanowire arrays (TiO2/Cu2O core/shell NWAs). When used as photoelectrode, the fabricated TiO2/Cu2O core/shell NWAs show improved photoelectrochemical (PEC) water splitting activity to pure TiO2 NWAs. The effects of the CBD cycle times on the PEC activities have been studied. The TiO2/Cu2O core/shell heterojunction nanowire array photoelectrode prepared by cycling 5 times in the CBD process achieves the highest photocurrent of 2.5 mA cm−2, which is 2.5 times higher than that of pure TiO2 NWAs. In addition, the H2 generation rate of this photoelectrode reaches to 32 μmol h−1 cm−2, 1.7 times higher than that of pure TiO2 NWAs. Furthermore, the TiO2/Cu2O core/shell heterojunction nanowire array photoelectrode shows excellent photostability and achieves a stable photocurrent of over 2.3 mA cm−2 during long light illumination time of 5 h. The enhanced photocatalytic activity of TiO2/Cu2O core/shell heterojunction nanowire array photoelectrode is attributed to the synergistic actions of TiO2 and Cu2O for improving visible light harvesting, and efficient transfer and separation of photogenerated electrons and holes.

In this paper, we designed a series of well-aligned ZnO nanorod arrays decorated with loading-controllable Au nanoparticles and studied their surface plasmon-driven photoelectrochemical (PEC) water splitting performances. The PEC water splitting ability of Au-ZnO nanorod arrays was evaluated under illumination with λ > 420 nm light. These nanorod arrays show remarkable PEC water splitting performances and achieve the highest photocurrent density of 30 μA cm−2 at 0.8 V versus Ag/AgCl. Furthermore, the PEC performance for heterogenous nanorod arrays can be effectively adjusted by controlling loading amounts of Au nanoparticles. We experimentally demonstrate that the Au-ZnO nanorod arrays show enhanced visible light absorption ability. The superior PEC performance of Au-ZnO nanorod arrays is attributed to the synergistic effects of plasmonic Au nanoparticles, ZnO semiconductor and Schottky barrier built in heterogenous nanorod array. This work provides a facile strategy to manipulate the PEC water splitting activity of Au-ZnO hybrid nanostructures by simply controlling the loading amounts of metallic Au nanoparticles. Furthermore, our research offers a potentially efficient strategy for the design and fabrication of new types of plasmonic-metal/semiconductor hybrid nanostructures with a plasmonic-enhanced PEC water splitting activity under the visible light, which are as valuable photocatalysts for solar-to-chemical/electrical energy conversion.

A highly sensitive, recyclable and self-cleaning surface-enhanced Raman scattering (SERS) substrate for rapid in situ monitoring photocatalytic degradation of dyes has been fabricated by growing Ag nanoparticles (NPs) on three-dimensional (3D) nanosheet-built ZnO microspheres (MSs). Used as a SERS substrate for the detection of Rhodamine 6 G (R6 G) molecules, the fabricated 3D Ag/ZnO MSs display high sensitivity and reproducibility as well as outstanding self-cleaning ability. The 3D Ag/ZnO MSs can detect the SERS signals of R6 G molecules even at very low concentration of 10-9 M. In the light of these outstanding performances, the 3D Ag/ZnO MSs were employed as a SERS-active substrate for rapid in situ monitoring photocatalytic degradation of R6 G molecules. The experimental results distinctively demonstrate that the enhanced photocatalytic degradation of R6 G molecules is attributed to the efficient plasmon-induced charge transfer at the interface of the Ag NPs, ZnO MSs and R6 G molecules. The as-prepared 3D Ag/ZnO MSs display potential applications for as a multifunctional platform to rapid in situ monitoring photocatalytic degradation of organic pollutants in polluted water.

In this study, a novel photoanode of ternary CdS/ZnFe2O4/Cu2O core/shell heterojunction nanorod arrays (NRAs) was fabricated via combining two-step hydrothermal method with a facile chemical bath deposition process. Under bias-free visible light irritation, the photocurrent density of the CdS/ZnFe2O4/Cu2O core/shell nanorod array (NRA) photoanode is 3.3 mA cm−2, 2.2 and 3.3-fold as high as that of CdS/ZnFe2O4 and CdS NRAs, respectively. In addition, an average H2 generation rate of the CdS/ZnFe2O4/Cu2O core/shell NRA photoanode is as high as 134 μmol h-1, 2.2-fold of CdS/ZnFe2O4 and 4.5-fold of CdS NRA photoanodes. Furthermore, the CdS/ZnFe2O4/Cu2O core/shell NRA photoanode shows a good photostability and achieves a photocurrent density of over 3 mA cm−2 during continuous light irradiation of 2 h. Significant enhancement for H2 evaluation of the CdS/ZnFe2O4/Cu2O core/shell NRA photoanode is ascribed to the efficient charge transfer and separation, which is achieved by its novel band alignment of stair-like type-II structure.

In this study, a novel three-dimensional (3D) CdS@Ni(OH)2 nanorod array (NRA) photoanode with a type-II band alignment and a p-n junction has been designed and constructed via a simple electrochemical deposition of hierarchical β-Ni(OH)2 nanosheets onto the surfaces of the CdS NRAs. The 3D CdS@Ni(OH)2 NRA photoanode fabricated under the optimal deposition current exhibits remarkably improved photoelectrochemical water splitting performance, and obtains a photocurrent density of up to 1.1 mA/cm2, 5-fold that of the pure CdS NRA photoanode. Most importantly, the solar-to-hydrogen conversion efficiency of the 3D CdS@Ni(OH)2 NRA photoanode is 3.3-fold higher than that of the pure CdS NRA photoanode at 0.67 V vs. RHE. The electrochemical and photoluminescence emission measurements confirm that the enhanced PEC water splitting capability of the prepared 3D CdS@Ni(OH)2 NRA photoanode is attributed to the efficient charge separation, which is achieved by the synergistic action of the type-II energy alignment and the p-n junction.

For potential use as a topological insulator, thin square-like Bi2Te3 nanosheets, prepared via a facile solution-based method, were subjected to detailed micro-Raman spectral measurements. The results demonstrate remarkable activation of the infrared active A1u mode in the Raman spectra despite the forbidden nature of the odd-parity A1u mode for bulk Bi2Te3 crystals. Therefore, the results unambiguously prove the crystal symmetry breaking of the thin square-like Bi2Te3 nanosheets. This study illustrates the potential applicability of micro-Raman spectroscopy as a powerful nanometrology tool for investigating the optical properties of topological insulators.

High figures of merit is important and necessary for thermoelectric materials in a particular engineering application of thermoelectric generation. Crystalline is an important factor for the high figures of merit of thermoelectric materials. Single-crystalline structure Sb/Bi2Te3 supperlattice nanowires (SLNWs) were synthesised in large quantity by pulsed electrodeposition technology using porous anodic alumina oxide as a template. The X-ray diffraction result indicates that the as-prepared compound consists of rhombohedral phase Bi2Te3 and monoclinic phase Sb. Transmission electron microscope images demonstrate that the segments of SLNWs are built by Bi2Te3 and Sb alternately and exhibit the distinguished interface between two segments. The average diameter and length of each segment are about 80 and 90 nm, respectively. The composition of neighbouring segments was investigated by selected area electron diffraction (SAED), further verifying that the neighbouring segments of SLNWs are comprised of Bi2Te3 and Sb. Meanwhile, the spot pattern of SAED indicates these segments are crystallised well.

A new series of metal (II) organophosphates with the formula M(II) 2(H 2 O) 2 [O 3 PCH 2 (C 6 H 4 )CH 2 PO 3 ] ( M =Mn, Fe and Ni) have been prepared by hydrothermal synthesis. The structure consisted of two-dimensional metal–oxygen inorganic layers is pillared by p-xylylenediphosphonate to form a three dimensional framework. The layers are constructed by corner-sharing metal oxygen polyhedron. A study on the magnetism of the materials indicates the presence of spin canted antiferromagnetc interactions. The manganese and iron compounds represent the interesting 3D metal organophosphate molecular metamagnet due to spin canted antiferromagnetic with high critical temperature (40 K for Mn; 16 K for Fe). The infinite M–O–M layers are believed to be responsible for this high performance.

Abstarct Hexagonal bismuth telluride (Bi 2 Te 3 ) 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 Bi 2 Te 3 nanostructures. The results indicate that alkaline additive NaOH is not necessary for the formation of Bi 2 Te 3 nanostructures in a solvothermal process. However, NaOH plays an important role in determining the morphology and size of Bi 2 Te 3 nanostructures. When the experiment was carried out with NaOH concentration ranging from 5 to 7 M, hexagonal Bi 2 Te 3 nanoplates with edge length of 140–280 nm were synthesized. When the experiment was carried out at higher NaOH concentration of 9–11 M, hexagonal Bi 2 Te 3 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 Bi 2 Te 3 nanorings which may have some scientific and technological applications in various functional devices.

CoFe 2 O 4 nanowire arrays were fabricated by electrodeposition of Fe 2+ and Co 2+ into anodic aluminum oxide (AAO) templates and further oxidization. The phase structure of the nanowires is cubic spinel-type, and the XRD result exhibits perfect preferred crystallite orientation along the nanowire axes. Compared with CoFe 2 O 4 nanowire arrays synthesized by other methods, the magnetic hysteresis loops demonstrate that the arrays of nanowires exhibit uniaxial magnetic anisotropy with easy magnetization direction along the nanowire axes owing to the large shape anisotropy. This approach provides a facile technology to fabricate oxide nanowires with uniaxial magnetic anisotropy.

Arrays of nanocables were electrodeposited into anodic aluminum oxide template at 40 °C in the solution of dimethylsulfoxide (DMSO) with 17 g/l FeCl 3 . The transmission electron microscope result clearly shows that the nanocables consist of light Fe–DMSO sheaths and dark Fe nanowire cores. The Fe nanowire cores are bcc structure with a preferred orientation of (1 1 0) and the sheaths of Fe–DMSO are coordination compounds of Fe with DMSO. The chemical bonds of Fe–DMSO are instable at high-temperature solution, so the content of Fe–DMSO decreases and that of Fe increases with the enhancing of electrodeposited temperature. All arrays of nanocables at different electrodeposited temperatures show an obvious anisotropy with the easy magnetizing axial parallel to the length of nanocable. With the applied field along the nanocable, the anisotropy, coercivity and squareness increase with the raise of electrodeposited temperature.

The coaxial nanocables of Fe/Fe-dimethylsulfoxide (DMSO) were electrodepositied at 40 degrees C in the solution of DMSO with 17 g/L FeCl3. It is the first report about the preparation of nanocables by electrodeposition in a simple one-step process. The Fe-DMSO sheaths are predicted as coordination compounds of [Fe(DMSO)(4)Cl-2)] and [Fe(DMSO)(3)Cl-3] that are amorphous in structure and paramagnetic at room temperature. The Fe cores are bcc structure with a preferred orientation of (110). The morphology of resulting nanostructures can be precisely controlled by varying the concentration of FeCl3 in DMSO solution and the elelctrodeposited temperature. The walls of Fe-DMSO sheaths are very thin; therefore, the outer diameters of nanocables are nearly the same as the central Fe cores about 40 nm, with an aspect ratio of 100. The arrays exhibit an obvious anisotropy with the easy magnetizing axis along the length of nanocables, which are useful magnetic storage materials.

Arrays of Fe 61 Co 27 P 12 nanowire with an aspect ratio about 70 were prepared in anodic aluminum oxide templates by electrodeposition. The influences of annealing temperature on structure and magnetic properties of Fe 61 Co 27 P 12 nanowires were studied. When the specimens were annealed below 400 °C, there are no obvious changes in structure except relaxation. With the annealing temperature increasing from 400 to 600 °C, the Fe–Co phase is detected by X-ray diffraction and Mossbauer spectra. The crystalline fraction and hyperfine field can be derived from Mossbauer spectra. The room temperature magnetic hysteresis loops show that the coercivity and squareness of the nanowire arrays in parallel to the wire axis increase with the increasing of annealing temperature, which mainly attributes to the strengthening of anisotropy.

Ag/Bi2Te3 superlattice nanowire arrays have been fabricated by pulse electrodeposition using porous anodic aluminium oxide as the template at large-scale quantity. The nanowire arrays were characterised by X-ray diffraction, a scanning electron microscope, a transmission electron microscope and high-resolution transmission electron microscopy (HRTEM). The results indicate that the nanowires are composed of the Bi2Te3 rhombohedral lattice phase and the Ag cubic lattice phase with alternately ordered multi-segment characters. The feature of dark segments alternated with bright segments can be easily distinguished because of the obvious heterogeneous contrast. The length of each segment varies from 25 to 45 nm. The HRTEM result shows that the composition of one segment is Ag and the neighbouring segment is Bi2Te3.

Amorphous Co–Zn alloy nanowire arrays with diameter of about 40 nm were fabricated in anodic aluminium oxide films by the electrodeposition method. Transmission electron microscope result shows that the nanowires are regular and uniform. Selected area electron diffraction and X-ray diffraction results indicate that the structure of nanowires is amorphous. Vibrating sample magnetometer is employed to study the magnetic properties of nanowire arrays at room temperature. The results show that the arrays of nanowires exhibit uniaxial magnetic anisotropy with the easy magnetization direction along the nanowire axes owing to the large shape anisotropy. When the applied magnetic field is parallel to the wire axis, the coercivity and squareness of the nanowire arrays decrease with increasing Zn concentration.

Arrays of Nd 5 Fe 95 − x B x (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.

Self-organized and ordered CoFe 2 O 4 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.

Fe-rich Fe96-xZrxB4 (0≤x≤7) nanowires were first prepared by electrodepositing into anodic aluminum oxide templates. Transmission electron microscope analysis shows that the nanowires are uniform and are about 100 nm in diameter with an aspect ratio of around 75. The broad peaks of X-ray diffraction and the Mossbauer spectrum indicate that the Fe96-xZrxB4 nanowires are composed of α-Fe-like and Zr-rich FeZrB phases. Selected area electro diffraction results also indicate that the structure of Fe89Zr7B4 nanowires is amorphous. A vibrating sample magnetometer is employed to study the magnetic properties of nanowire arrays at room temperature. The coercivity of nanowire arrays in parallel to the wire axis decreases with increasing Zr content.

Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity are prepared by a facile and simple solid state reaction at room temperature. The composition, morphology and optical properties of the as-prepared Ag3PO4 microcrystals are characterized by x-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra. The photocatalytic properties of Ag3PO4 are investigated by the degradation of both methylene blue and methyl orange dyes under visible light irradiation. The as-prepared Ag3PO4 microcrystals possess high photocatalytic oxygen production with the rate of 673 μmolh−1 g−1. Moreover, the as-prepared Ag3PO4 microcrystals show an enhanced photoelectrochemistry performance under irradiation of visible light.

We report the room temperature ferromagnetism (RTF) of pure ZnO nanoparticles, which were prepared by coprecipitation method. Magnetization measurement indicates that the ZnO nanoparticles annealed in air at 450, 550, 650, and 800 °C exhibit the RTF and the decrease in the ferromagnetism is performed with the increase in annealed temperature. Selected area electron diffraction, x-ray diffraction, and x-ray photoelectron spectroscopy measurements show that all the samples possess a typical wurtzite structure and no other impurity phases are observed. The results of the Raman spectra indicate that there are lots of defects existing in the fabricated samples. It is also found that the ferromagnetism of ZnO nanoparticles increases after annealing in vacuum condition and decreases after annealing in a rich-oxygen atmosphere. These results confirm that the oxygen vacancies play an important role in introducing ferromagnetism for the ZnO nanoparticles in our case.