Developing Z-scheme Bi2MoO6@α-MnO2 beaded core-shell heterostructure in photoelectrocatalytic treatment of organic wastewater.

Photoelectrocatalysis (PEC) oxidation technology with the combination of electrocatalysis and photocatalysis is an ideal candidate for treatment of dyeing wastewater containing multifarious intractable organic compounds with high chroma. Constructing high-quality heterojunction photoelectrodes can effectively suppress the recombination of photo-generated carriers, thereby achieving efficient removal of pollution. Herein, a beaded Bi2MoO6@α-MnO2 core-shell architecture with tunable hetero-interface was prepared by simple hydrothermal-solvothermal process. The as-synthesized Bi2MoO6@α-MnO2 had larger electrochemically active surface area, smaller charge transfer resistance and negative flat band potential, and higher separation efficiency of e-/h+ pairs than pure α-MnO2 or Bi2MoO6. It is noteworthy that the as-synthesized Bi2MoO6@α-MnO2 showed Z-scheme heterostructure as demonstrated by the free radical quenching experiments. The optimized Bi2MoO6@α-MnO2-2.5 exhibited the highest degradation rate of 88.64% in 120 min for reactive brilliant blue (KN-R) and accelerated stability with long-term(∼10000s) at the current density of 50 mA cm-2 in 1.0 mol L-1 H2SO4 solution. This study provides valuable insights into the straightforward preparation of heterogeneous electrodes, offering a promising approach for the treatment of wastewater in various industrial applications.

Chemical Bath Deposition of ZnO/ZnGa2O4 Core-Shell Nanowire Heterostructures Using Partial Chemical Conversion.

The development of innovative heterostructures made of ZnO nanowires is of great interest for enhancing the performances of many devices in the fields of optoelectronics, photovoltaics, and energy harvesting. We report an original fabrication process to form ZnO/ZnGa2O4 core-shell nanowire heterostructures in the framework of the wet chemistry techniques. The process involves the partial chemical conversion of ZnO nanowires grown via chemical bath deposition into ZnO/ZnGa2O4 core-shell nanowire heterostructures with a high interface quality following their immersion in an aqueous solution containing gallium nitrate heated at a low temperature. The double-step process describing the partial chemical conversion relies on successive dissolution and reaction mechanisms. The present finding offers the possibility to fabricate ZnO/ZnGa2O4 core-shell nanowire heterostructures at low temperatures and over a wide variety of substrates with a large surface area, which is attractive for nanostructured solar cells, deep-UV photodetectors, and piezoelectric devices.

Rigid CuInS2/ZnS Core/Shell Quantum Dots for High Performance Infrared Light-Emitting Diodes.

CuInS2 (CIS) quantum dots (QDs) represent an important class of colloidal materials with broad application potential, owing to their low toxicity and unique optical properties. Although coating with a ZnS shell has been identified as a crucial method to enhance optical performance, the occurrence of cation exchange has historically resulted in the unintended formation of Cu-In-Zn-S alloyed QDs, causing detrimental blueshifts in both absorption and photoluminescence (PL) spectral profiles. In this study, we present a facile one-pot synthetic strategy aimed at impeding the cation exchange process and promoting ZnS shell growth on CIS core QDs. The suppression of both electron-phonon interaction and Auger recombination by the rigid ZnS shell results in CIS/ZnS core/shell QDs that exhibit a wide near-infrared (NIR) emission coverage and a remarkable PL quantum yield of 92.1%. This effect boosts the fabrication of high-performance, QD-based NIR light-emitting diodes with the best stability of such materials so far.

CdS/ZnS core-shell nanorod heterostructures co-deposited with ultrathin MoS2 cocatalyst for competent hydrogen evolution under visible-light irradiation.

Hydrogen generation via semiconductor photocatalysts has gained significant attention as a sustainable fuel generation process. To demonstrate the performance of nanoscale core-shell heterostructure in photocatalytic hydrogen production, we have fabricated CdS nanorods coated with ZnS photocatalyst via wet-chemical reaction followed by deposition of ultrathin MoS2 nanosheets by photo reduction process. The effect of ZnS content and suitable amount of MoS2 loading over the visible-light induced photocatalytic hydrogen evolution was examined in Na2S and Na2SO3 aqueous solutions. Interestingly, it is apparent that a close connection (or heterojunction) between CdS and ZnS is believed to easily tunnel the charge carriers to the surplus surface states, making its electrons and holes energetically favourable to transfer from ZnS to MoS2 for photocatalytic reactions and subsequently, enhances the H2 evolution activity in CdS/ZnS type I core-shell heterostructures. The optimal MoS2 concentration is resolved to be 7 mol% and the subsequent visible-light induced H2 generation rate was 13589 µmol h-1g-1, which is 19 and 158 fold higher than pristine CdS and ZnS respectively. The probable photocatalytic mechanism of CdS/ZnS type I core-shell heterostructure with MoS2 cocatalyst is proposed. Our inexpensive and convenient preparation strategy may offer novel prospects in the engineering of desirable nanoheterostructures with better performance.

Construction of CoNi2S4/Co9S8@Co4S3 nanocubes derived from Ni-Co prussian blue analogues@cobalt carbonate hydroxide core-shell heterostructure for asymmetric supercapacitor.

Construction of Prussian blue analogues (PBAs) with heterostructure is beneficial to preparing PBAs derivatives with superior electrochemical performance. In this work, the core-shell nanostructured nanocubes composed of nickel hexacyanocobalt PBA (NiCo-PBA)@cobalt carbonate hydroxide (CCH) are synthesized through an in-situ epitaxial growth strategy, and the formation mechanisms of coating are carefully validated and specifically discussed. Then, the precursors are successfully transformed into hierarchical CoNi2S4/Co9S8@Co4S3 via the gas-phase vulcanization method. Benefiting from the intriguing heterostructure and multicomponent sulfides, the CoNi2S4/Co9S8@Co4S3-80 electrode exhibits a high specific capacity of 799 ± 16C/g (specific capacitance of 1595 ± 31F/g) at 1 A/g, ultra-high capacity retention of 80 % at a high current density of 20 A/g. The assembled asymmetric supercapacitor (ASC) device delivers a high energy density of 43.3 Wh kg-1 at a power density of 899 W kg-1 and exhibits superior cycling stability with the capacity retention of 88 % after 5,000 cycles. Subsequently, the fabricated all-solid-state ASC device shows an excellent energy density of 36.4 Wh kg-1 with a power density of 824 W kg-1. This work proposing rational design of combining multicomponent sulfides and core-shell heterostructure based on PBA nanocubes opens up a novel route for developing asymmetric supercapacitor electrode materials with superior performance.

Core-shell heterostructured Ni(OH)2@activation Zn-Co-Ni layered double hydroxides electrode for flexible all-solid-state coaxial fiber-shaped asymmetric supercapacitors.

The increasing requirements for wearable and portable electronics are driving the interests of high performance fiber supercapacitor. Layered double hydroxide (LDH) is broadly used in electrode materials, owing to the adjustability of components and the unique lamellar structure. However, limited active sites and poor electrical conductivity hinder its applications. Herein, the core-shell heterostructured Ni(OH)2@activation Zn-Co-Ni layered double hydroxides (Ni(OH)2@A-ZnCoNi-LDH) electrode was fabricated by loading pseudocapacitance material on the A-ZnCoNi-LDH to improve the electrochemical performance. Significantly, benefits from the synergistic effect of the multi-metal ions and the core-shell heterostructure, the electrodes demonstrated a capacitance of 2405 mF·cm-2 at 1 mA·cm-2. Furthermore, Ni(OH)2@A-ZnCoNi-LDH was used as the core electrode and carbon nanotube (CNT) film coated with Fe2O3@reduced graphene oxide (rGO) was wrapped around the core electrode to assemble coaxial fiber asymmetric supercapacitor, which illustrated an ultrahigh energy density of 177.7 µWh·cm-2 at 0.75 mW·cm-2. In particular, after consecutive charging and discharging 7000 cycles, the capacitance retention of the device was 95 %, indicating the excellent cycling stability. Furthermore, the device with high flexibility can be woven into textiles in different shapes. The fabricated device has an excellent development prospect as an energy source in wearable electronic devices.

Low Power Volatile and Nonvolatile Memristive Devices from 1D MoO2-MoS2 Core-Shell Heterostructures for Future Bio-Inspired Computing.

Memristors-based integrated circuits for emerging bio-inspired computing paradigms require an integrated approach utilizing both volatile and nonvolatile memristive devices. Here, an innovative architecture comprising of 1D CVD-grown core-shell heterostructures (CSHSs) of MoO2-MoS2 is employed as memristors manifesting both volatile switching (with high selectivity of 107 and steep slope of 0.6 mV decade-1) and nonvolatile switching phenomena (with Ion/Ioff ≈103 and switching speed of 60 ns). In these CSHSs, the metallic core MoO2 with high current carrying capacity provides a conformal and immaculate interface with semiconducting MoS2 shells and therefore it acts as a bottom electrode for the memristors. The power consumption in volatile devices is as low as 50 pW per set transition and 0.1 fW in standby mode. Voltage-driven current spikes are observed for volatile devices while with nonvolatile memristors, key features of a biological synapse such as short/long-term plasticity and paired pulse facilitation are emulated suggesting their potential for the development of neuromorphic circuits. These CSHSs offer an unprecedented solution for the interfacial issues between metallic electrodes and the layered materials-based switching element with the prospects of developing smaller footprint memristive devices for future integrated circuits.

Shape and Composition Evolution in an Alloy Core-Shell Nanowire Heterostructure Induced by Adatom Diffusion.

A core-shell nanowire heterostructure is an important building block for nanowire-based optoelectronic devices. In this paper, the shape and composition evolution induced by adatom diffusion is investigated by constructing a growth model for alloy core-shell nanowire heterostructures, taking diffusion, adsorption, desorption and incorporation of adatoms into consideration. With moving boundaries accounting for sidewall growth, the transient diffusion equations are numerically solved by the finite element method. The adatom diffusions introduce the position-dependent and time-dependent adatom concentrations of components A and B. The newly grown alloy nanowire shell depends on the incorporation rates, resulting in both shape and composition evolution during growth. The results show that the morphology of nanowire shell strongly depends on the flux impingement angle. With the increase in this impingement angle, the position of the largest shell thickness on sidewall moves down to the bottom of nanowire and meanwhile, the contact angle between shell and substrate increases to an obtuse angle. Coupled with the shell shapes, the composition profiles are shown as non-uniform along both the nanowire and the shell growth directions, which can be attributed to the adatom diffusion of components A and B. The impacts of parameters on the shape and composition evolution are systematically investigated, including diffusion length, adatom lifetime and corresponding ratios between components. This kinetic model is expected to interpret the contribution of adatom diffusion in growing alloy group-IV and group III-V core-shell nanowire heterostructures.

Interface engineered hydrangea-like ZnCo2O4/NiCoGa-layered double hydroxide@polypyrrole core-shell heterostructure for high-performance hybrid supercapacitor.

Rationally constructing advanced battery-type electrodes with hierarchical core-shell heterostructure is essential for improving the energy density and cycling stability of hybrid supercapacitors. Herein, this work successfully constructs hydrangea-like ZnCo2O4/NiCoGa-layered double hydroxide@polypyrrole (denoted as ZCO/NCG-LDH@PPy) core-shell heterostructure. Specifically, the ZCO/NCG-LDH@PPy employs ZCO nanoneedles clusters with large open void space and rough surfaces as the core, and NCG-LDH@PPy composite as the shell, comprising hexagonal NCG-LDH nanosheets with rich active surface area, and conductive PPy films with different thicknesses. Meanwhile, density functional theory (DFT) calculations authenticate the charge redistribution at the heterointerfaces between ZCO and NCG-LDH phases. Benefiting from the abundant heterointerfaces and synergistic effect among different active components, the ZCO/NCG-LDH@PPy electrode acquires an extraordinary specific capacity of 381.4 mAh g-1 at 1 A g-1, along with excellent cycling stability (89.83% capacity retention) after 10,000 cycles at 20 A g-1. Furthermore, the prepared ZCO/NCG-LDH@PPy//AC hybrid supercapacitor (HSC) exhibits a remarkable energy density (81.9 Wh kg-1), an outstanding power density (17,003.7 W kg-1), and superior cycling performance (a capacitance retention of 88.41% and a coulombic efficiency of 93.97%) at the end of the 10,000th cycle. Finally, two ZCO/NCG-LDH@PPy//AC HSCs in series can light up a LED lamp for 15 min, indicating its excellent application prospects.

Constructing Z-scheme NiMoO4@Co3O4 core-shell heterogeneous architectures with prominent photoelectrocatalytic performance toward water purification.

Photoelectrocatalysis (PEC) oxidation is an efficient and eco-friendly advanced oxidation process (AOP), which is a hot research topic in the treatment of organic wastewater. The selection of superior photoelectrode materials is the critical factor affecting PEC efficiency and the main challenge in practical application. In this work, novel NiMoO4@Co3O4 hierarchical core-shell heterogeneous photoanodes were prepared through a two-step hydrothermal method and exhibited superior catalytic performance in the degradation of reactive brilliant blue KN-R. The wrapping of NiMoO4 nanosheets on Co3O4 nanowires electrode can enlarge its contact area with electrolyte, enable fast redox reaction and improve the long-term durability. The unique Z-scheme heterojunction structure between the two components ensured the effective separation of photo-generated carriers, facilitating the generation of OH and O2- during the PEC degradation process. The optimal NiMoO4@Co3O4-1.25 hierarchical architecture anode catalyst exhibited the highest removal rate of 83.65% of reactive brilliant blue KN-R in 120 min with long-term stability (∼12000 s) in 1.0 mol·L-1 H2SO4 solution. This report may inspire the design and fabrication of heterostructure photoanode in water purification.

Core-shell Cu@C@ZIF-8 composite: a high-performance electrode material for electrochemical sensing of nitrite with high selectivity and sensitivity.

Herein, an efficient electrochemical sensing platform is proposed for selective and sensitive detection of nitrite on the basis of Cu@C@Zeolitic imidazolate framework-8 (Cu@C@ZIF-8) heterostructure. core-shell Cu@C@ZIF-8 composite was synthesized by pyrolysis of Cu-metal-organic framework@ZIF-8 (Cu-MOF@ZIF-8) in Ar atmosphere on account of the difference of thermal stability between Cu-MOF and ZIF-8. For the sensing system of Cu@C@ZIF-8, ZIF-8 with proper pore size allows nitrite diffuse through the shell, while big molecules cannot, which ensures high selectivity of the sensor. On the other hand, Cu@C as electrocatalyst promotes the oxidation of nitrite, thereby resulting high sensitivity of the sensor. Accordingly, the Cu@C@ZIF-8 based sensor presents excellent performance for nitrite detection, which achieves a wide linear response range of 0.1-300.0µM, and a low limit of detection of 0.033µM. In addition, the Cu@C@ZIF-8 sensor possesses excellent stability and reproducibility, and was employed to quantify nitrite in sausage samples with recoveries of 95.45%-104.80%.

Interfacial Control of NiCoP@NiCoP Core-Shell Nanoflake Arrays as Advanced Cathodes for Ultrahigh-Energy-Density Fiber-Shaped Asymmetric Supercapacitors.

Efficient improvement of the energy density and overall electrochemical performance of fiber-shaped asymmetric supercapacitors (FASCs) for practical applications in portable and wearable electronics requires highly electrochemically active materials and a rational design. Herein, two-step phosphorization (TSP) processes are performed to directly grow 3D well-aligned NiCoP@NiCoP (NCP@NCP TSP) nanoflake arrays (NFAs) on carbon nanotube fibers (CNTFs). Profiting from the metallic characteristics and excellent electrochemical performance of NiCoP and the hierarchical design of the core-shell heterostructure, the NCP@NCP TSP NFAs/CNTF hybrid electrode exhibits significantly improved electrochemical performance. The as-fabricated NCP@NCP TSP NFAs/CNTF electrode possesses an ultrahigh areal capacitance of 10 035 mF cm-2 at a current density of 1 mA cm-2 , with excellent rate capability and cycling stability. Furthermore, an FASC device with a maximum operating voltage of 1.6 V is assembled by adopting NCP@NCP TSP NFAs/CNTF as a positive electrode, hierarchical TiN@VN core-shell heterostructure nanowire arrays (NWAs)/CNTF as negative electrode, and KOH-PVA as a gel electrolyte. The FASC device exhibits a high areal capacitance of 430.4 mF cm-2 and an ultrahigh energy density of 51.02 mWh cm-3 . Thus, the rationally designed NiCoP@NiCoP electrode is a promising candidate for incorporation into next-generation wearable and portable energy-storage devices.

Nitride-Oxide-Metal Heterostructure with Self-Assembled Core-Shell Nanopillar Arrays: Effect of Ordering on Magneto-Optical Properties.

Magneto-optical (MO) coupling incorporates photon-induced change of magnetic polarization that can be adopted in ultrafast switching, optical isolators, mode convertors, and optical data storage components for advanced optical integrated circuits. However, integrating plasmonic, magnetic, and dielectric properties in one single material system poses challenges since one natural material can hardly possess all these functionalities. Here, co-deposition of a three-phase heterostructure composed of a durable conductive nitride matrix with embedded core-shell vertically aligned nanopillars, is demonstrated. The unique coupling between ferromagnetic NiO core and atomically sharp plasmonic Au shell enables strong MO activity out-of-plane at room temperature. Further, a template growth process is applied, which significantly enhances the ordering of the nanopillar array. The ordered nanostructure offers two schemes of spin polarization which result in stronger antisymmetry of Kerr rotation. The presented complex hybrid metamaterial platform with strong magnetic and optical anisotropies is promising for tunable and modulated all-optical-based nanodevices.

Photosensitive activity of fabricated core-shell composite nanostructured p-CuO@CuS/n-Si diode for photodetection applications.

Development of photo detectors based on different semiconducting materials with high performance has been in progress in recent past, however, there is a lot of difficulties in developing the more effective photo detectors-based devices with high responsivity, detectivity and quantum efficiency. Hence, we have synthesized pure CuS and CuO@CuS core-shell heterostructure based photo detectors with high performance by simple and cost-effective two-step chemical co-precipitation method. The phase purity of CuS and CuO@CuS composite was observed by XRD analysis and the result were verified with Raman spectroscopy studies. Sphere like morphology of pure CuS and core-shell structure formation of CuO@CuS are observed with scanning and transmission electron microscopes. The presence of expected elements has been confirmed with EDX elemental mapping. Light harvesting photodiodes were fabricated by using n-type silicon substrate through drop cost method. Photo sensitive parameters of fabricated diodes were analyzed by I-V characteristics. The p-CuO@CuS (1:1)/n-Si diode owned a maximum photosensitivity (Ps) ∼ 7.76 × 104 %, photoresponsivity (R) ∼ 798.61 mA/W, external quantum efficiency ( E Q E )∼309.66 % and specific detectivity (D*) ∼ 8.19 × 1011 Jones when compared to p-CuS/n-Si diode. The obtained results revealed that the core/shell heterostructure of CuO@CuS is the most appropriate for photo detection.

Facile synthesis of Fe3O4/CuO a core-shell heterostructure for the enhancement of photocatalytic activity under visible light irradiation.

A magnetically separable Fe3O4/CuO core-shell heterostructure photocatalyst was synthesized by hydrothermal method. The obtained photocatalyst was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-visible diffuse reflectance (UV-DRS). The obtained photocatalyst was used for the degradation of azo dye Direct Red 89 (DR89), under visible light irradiation provided by fluorescent lamp of 100 W in the presence of 7 mL of H2O2 (30%); the results of the photocatalytic activity for Fe3O4/CuO photocatalyst showed that in the presence of 0.75 g dispersed in 250 mL of 40 mg/L of DR89 dye at pH 6 the dye was completely removed after 240 min. Moreover, the photocatalytic activity of the prepared Fe3O4/CuO was enhanced 11 and 9 times compared with the pure Fe3O4 or CuO. The effect of initial dye concentrations on the photocatalytic activity was studied in the range of 20-60 mg/L, and the results showed that the catalyst has a good photocatalytic activity of 89% even at high concentration (60 mg/L). Furthermore, the catalyst maintained its activity after 5 cycles, and its paramagnetic property facilitates its recovery. The excellent photodegradation activity of Fe3O4/CuO was attributed to the low band gap of the catalyst equal to 1.54 eV and the enhancement of light absorption in visible range of 330-780 nm, but also to a better charge carriers separation, due to the presence of Fe3O4 that reduces electron/hole recombination.

TiO2-on-C3N4 double-shell microtubes: In-situ fabricated heterostructures toward enhanced photocatalytic hydrogen evolution.

Structural design, doping, and construction of heterojunctions are effective strategies for producing highly efficient photocatalytic materials. Herein, N-doped TiO2 was formed on hexagonal C3N4 tube through in-situ hydrolysis of a Ti source on a supramolecular precursor, followed by thermal treatment. As a result, a double-shell microtube, C3N4@TiO2 heterostructure was fabricated. It was worth noting that the supramolecular precursor was prepared from melamine and cyanuric acid, which not only served as a template for the double-shell tubular structure, but also provided nitrogen for the doping of TiO2. The photocatalytic efficiency of C3N4@TiO2 was investigated by conducting hydrogen production experiments. The hydrogen production rate of C3N4@TiO2 was measured to be 10.1 mmol h-1 g-1, which is 4 times and 15 times that of C3N4 and TiO2, respectively. The improved photocatalytic activity of C3N4@TiO2 can be ascribed to (1) the tubular structure that provides a large number of reaction sites and enhances mass transport, (2) the heterojunction that is beneficial to charge separation, and (3) doping of TiO2 with nitrogen which extends its optical absorption range to visible light. This work demonstrates a facile method for synthesizing a highly efficient photocatalyst towards hydrogen evolution by modifying its structure and chemical composition as well as forming a heterojunction.

Promoting the spatial charge separation by building porous ZrO2@TiO2 heterostructure toward photocatalytic hydrogen evolution.

The robust photocatalytic hydrogen evolution (PHE) from water needs an effective photogenerated charge spatial separation and enough contact between reactant and catalyst, but the synthesis of catalysts with the characteristics remains a challenge. Herein, we report the design of core-shell heterostructure consisted of thin TiO2 layer uniformly coated on porous ZrO2 polyhedron for effective PHE. In this system, UiO-66-NH2, one of popular MOF with Zr as metal node, has been chosen as the precursor template due to its plentiful pores, uniform morphology, as well as the rich NH2 groups. Our results show that Ti precursor can uniformly coat on UiO-66-NH2, by means of interaction of tetrabutyl titanate (TBT) with -NH3 in UiO-66-NH2. Followed by the calcination, the Ti precursor and UiO-66-NH2 can be converted into ZrO2 and TiO2, respectively, thus leading to the formation of ZrO2@TiO2 core-shell heterostructure. The ZrO2@TiO2-500 has the high specific surface area of 52.4 m2 g-1. Besides, the intimate contact of TiO2 shell with ZrO2 core facilitates the separation and migration of photoinduced carriers, exposing more active sites for the surface photocatalytic hydrogen evolution reaction. The spectrum and electrochemical characterization further exhibit the extended life of photon-generated carrier and easy mass transfer. The optimized ZrO2@TiO2-500 shows enhanced photocatalytic rate of 39.7 mmol h-1 g-1, much higher than those of ZrO2 (0.8 mmol h-1 g-1) and TiO2 (7.6 mmol h-1 g-1).

Gold-Sensitized Silicon/ZnO Core/Shell Nanowire Array for Solar Water Splitting.

Solar water splitting represents one of the most promising strategies in the quest for clean and renewable energy. However, low conversion efficiency, use of sacrificial agents, and external bias for current water splitting system limit its practical application. Here, a gold-sensitized Si/ZnOcore/shell nanowire photoelectrochemical (PEC) cell is reported for efficient solar water oxidation. We demonstrated gold-sensitized n-Si/n-ZnO nanowire arrays exhibited higher energy conversion efficiency than gold-sensitized p-Si/n-ZnO nanowire arrays due to the favorable energy-band alignment characteristics. Without any assistance from an external electrical source and sacrificial reagents, gold-sensitized n-Si/n-ZnO core/shell nanowire array photoanode achieved unbiased water splitting under simulated solar light illumination. This method opens a promising venue to cost-efficient production of solar fuels.

One-Step Low Temperature Hydrothermal Synthesis of Flexible TiO2/PVDF@MoS2 Core-Shell Heterostructured Fibers for Visible-Light-Driven Photocatalysis and Self-Cleaning.

Novel flexible and recyclable core-shell heterostructured fibers based on cauliflower-like MoS2 and TiO2/PVDF fibers have been designed through one-step hydrothermal treatment based on electrospun tetrabutyl orthotitanate (TBOT)/PVDF fibers. The low hydrothermal temperature avoids the high temperature process and keeps the flexibility of the as-synthesized materials. The formation mechanism of the resultant product is discussed in detail. The composite of MoS2 not only expands the light harvesting window to include visible light, but also increases the separation efficiency of photo-generated electrons and holes. The as-prepared product has proven to possess excellent and stable photocatalytic activity in the degradation of Rhodamine B and levofloxacin hydrochloride under visible light irradiation. In addition, the TiO2/PVDF@MoS2 core-shell heterostructured fibers exhibit self-cleaning property to dye droplets under visible light irradiation. Meanwhile, due to its hydrophobicity, the resultant product can automatically remove dust on its surface under the rolling condition of droplets. Hence, the as-prepared product cannot only degrade the contaminated compounds on the surface of the material, but also reduce the maintenance cost of the material due to its self-cleaning performance. Therefore, the as-prepared product possesses potential applications in degradation of organic pollutants and water treatment, which makes it a prospective material in the field of environmental treatment.

Coupling Resonances of Surface Plasmon in Gold Nanorod/Copper Chalcogenide Core-Shell Nanostructures and Their Enhanced Photothermal Effect.

Dual plasmonic Au@Cu2-x S core-shell nanorods (NRs) have been fabricated by using a hydrothermal method and plasmon-coupled effect between the Au core and Cu2-x S shell in the near-infrared (NIR) region. The extinction spectrum of Au@Cu2-x S NRs is dominated by the surface plasmon resonance (SPR) of the Cu2-x S shell, the transverse surface plasmon resonance (TSPR), and the longitudinal surface plasmon resonance (LSPR) of the Au NRs. With the Cu2-x S shell increasing (fixed Au NRs), the TSPR peak slightly redshifts and the LSPR and SPR peaks blueshift, owing to competition between the redshift of the refractive index effect and blueshift from the plasmon coupled effect. Although, for Au@Cu2 S NRs, only TSPR and LSPR peaks can be seen and a redshift arises with the increasing Cu2 S shell thickness, implying that no plasmonic coupling between Au NRs and Cu2 S shell occurred. The extinction spectrum of the Au@Cu2-x S NRs with three coupled resonance peaks is simulated by using the FDTD method, taking into account the electron-transfer effect. The dispersion properties of the coupling of Au@Cu2-x S NRs with the LSPR of the initial Au core are studied experimentally by changing the length of the Au NRs, which are explained theoretically by the coupled harmonic oscillator model. The calculated coupled coefficients between SPR of the Cu2-x S shell and LSPR of the Au NRs is 180 meV, which is much stronger than that of TSPR of Au NRs of 55 meV. Finally, the enhanced photothermal effect of Au@Cu2-x S NRs has been demonstrated.