Nanorod Templates Research Articles

Interface engineering of Bi2O3/Ag/TiO2 nanotubes heterojunction photodetector for UV imaging and optical communication

Large-scale Bi2O3/Ag/TiO2 nanotubes (BAT NTs) were successfully synthesized using ZnO nanorods template through the facile solution process at room temperature. Highly ordered BAT NTs with an average diameter of approximately 300 nm were arranged hierarchically on the overall ITO substrate. In addition, a self-powered UV photodetector (UVPD) based on BAT NTs was assembled and the photoresponse characteristics were investigated under a wide range of UV light intensity. The BAT NTs UVPD exhibits satisfactory UV photodetection performance with detectivity of 1.55 × 1010 Jones and on/off ratio exceeding 103, associated with a fast response speed of 25 ms, which is ascribed to the efficient carrier transport inspired by the 1D structure and energy band structure. In addition, BAT NTs UVPD also features excellent environmental stability and long cycling stability. Benefitting from the desirable properties, the BAT NTs UVPD achieves high-resolution imaging results with “UV” pattern as a single pixel unit and performs accurate UV optical communication as a signal receiver at zero bias. Eventually, the detailed self-powered UV detection mechanism for BAT NTs UVPD was illustrated.

Rod-to-sphere elemental reconstruction of biocompatible Ag2Te-Ag4.53-Te3 nanoparticles for triple negative breast cancer photo-nano-therapy.

Silver nanoparticles (AgNPs) continue to be applied to agricultural and medical applications because of their antibacterial and antifungal effects. However, AgNPs are vulnerable to poisoning by oxidation or sulfidation, and unintentional toxicity can occur via leaching. Therefore, ensuring the stability of AgNPs for practical applications is considered an important requirement. In this study, we propose the solvothermal galvanic replacement of a Te nanorod (TeNR) template with a Ag precursor to manufacture highly stable and biocompatible Ag-Te nanoparticles (AgTeNPs). In addition to their high stability, AgTeNPs composed of Ag2Te-Ag4.53Te3 were evaluated as a nanotherapeutic agent enabled by their selective toxicity through metabolic degradation in breast cancer cells. It has been demonstrated that combinatorial treatment with hyperthermic cancer-cell ablation through photothermal conversion provides an effective cancer treatment in vitro and in vivo. The discovered new biocompatible Ag nanomaterials with innate anticancer effects are expected to be applied to various application fields.

Designer-length palladium nanowires can be templated by the central channel of tobacco mosaic virus nanorods

We have developed methods for the templated synthesis of palladium nanowires (Pd NWs) within the central channel of tobacco mosaic virus (TMV) nanorods of various lengths. We show that uniform 4 nm diameter Pd NWs can be produced by selective growth within these channels by including the capping reagent, poly(vinyl-pyrrolidone) (PVP30K) and reducing the metal precursor to metallic palladium with ascorbic acid. The length of the Pd NWs can be controlled either by varying the length of the nanorod templates and/or through alterations to the reaction conditions. We have also demonstrated bimetallic gold (Au)-palladium (Pd) in-situ metallization of TMV nanorods resulting in the production of Pd NWs 6 nm gold nanoparticles attached to their ends. The materials produced have many potential applications in the construction of nanoscale devices.

Crystal Design and Photoactivity of TiO2 Nanorod Template Decorated with Nanostructured Bi2S3 Visible Light Sensitizer.

In this study, TiO2-Bi2S3 composites with various morphologies were synthesized through hydrothermal vulcanization with sputtering deposited Bi2O3 sacrificial layer method on the TiO2 nanorod templates. The morphologies of decorated Bi2S3 nanostructures on the TiO2 nanorod templates are controlled by the duration of hydrothermal vulcanization treatment. The Bi2S3 crystals in lumpy filament, nanowire, and nanorod feature were decorated on the TiO2 nanorod template after 1, 3, and 5 h hydrothermal vulcanization, respectively. Comparatively, TiO2-Bi2S3 composites with Bi2S3 nanowires exhibit the best photocurrent density, the lowest interfacial resistance value and the highest photodegradation efficiency towards Rhodamine B solution. The possible Z-scheme photoinduced charge separation mechanism and suitable morphology of Bi2S3 nanowires might account for the high photoactivity of TiO2 nanorod-Bi2S3 nanowire composites.

Rhodium-Tellurium Nanorod Synthesis Using Galvanic Replacement-Polyol Regrowth for Thermo-Dynamic Dual-Modal Cancer Phototherapy.

Rh is a noble metal introduced in bioapplications, including diagnosis and therapy, in addition to its consolidated utilization in organic catalysis and electrocatalysis. Herein, we designed the synthesis of highly crystalline Rh nanocrystal-decorated Rh-Te nanorods (RhTeNRs) through galvanic replacement of sacrificial Te nanorod (TeNR) templates and subsequent polyol regrowth. The obtained RhTeNRs showed excellent colloidal stability and efficient heat dissipation and photocatalytic activity under various laser irradiation wavelengths. Based on the confirmed biocompatibility, RhTeNRs were introduced into in vitro and in vivo cancer phototherapies. The results confirmed the selective physical death of cancer cells in the local area through laser irradiation. While chemotherapy does not guarantee successful treatment due to side effects and resistance, phototherapy using heat and reactive oxygen species generation of RhTeNRs induces physical death.

Sputtering-Assisted Synthesis of Copper Oxide-Titanium Oxide Nanorods and Their Photoactive Performances.

A TiO2 nanorod template was successfully decorated with a copper oxide layer with various crystallographic phases using sputtering and postannealing procedures. The crystallographic phase of the layer attached to the TiO2 was adjusted from a single Cu2O phase or dual Cu2O–CuO phase to a single CuO phase by changing the postannealing temperature from 200 °C to 400 °C. The decoration of the TiO2 (TC) with a copper oxide layer improved the light absorption and photoinduced charge separation abilities. These factors resulted in the composite nanorods demonstrating enhanced photoactivity compared to that of the pristine TiO2. The ternary phase composition of TC350 allowed it to achieve superior photoactive performance compared to the other composite nanorods. The possible Z-scheme carrier movement mechanism and the larger granular size of the attached layer of TC350 under irradiation accounted for the superior photocatalytic activity in the degradation of RhB dyes.

A facile template-assisted synthesis of large-scale Bi2O3 nanotube arrays for self-powered UV photodetector

Large-scale Bi2O3 nanotubes (NTs) arrays were successfully synthesized on ITO substrate with the assistance of ZnO nanorods template at room temperature. The as-synthesized highly orientated Bi2O3 NTs with an average diameter of ∼95 nm were well distributed throughout the entire substrate. Moreover, Bi2O3 NTs were employed to construct the ultraviolet photodetector (UVPD). Received to UV irradiation, the Bi2O3 NTs UVPD displayed a high average current density of 40.4 μA/cm2, coupled with fast average rise time of ∼28.8 ms and decay time of ∼40.9 ms. Furthermore, the Bi2O3 NTs UVPD could carry out accurate UV detection without external bias as well as maintain good stability and repeatability. Additionally, the UV detection mechanism of the as-assembled Bi2O3 NTs UVPD was also discussed.

Tetrafunctional template-assisted strategy to preciously construct co-doped Sb@C nanofiber with longitudinal tunnels for ultralong-life and high-rate sodium storage

Antimony (Sb) is an attractive alloy-type anode material for sodium-ion batteries (SIBs) owing to its high theoretical capacity and the very appropriate reaction potential. However, it suffers from rapid capacity fading and poor rate performance caused by the huge volume changes (∼390%) and sluggish kinetics during sodiation and desodiation, severely hindering its practical application. Structural or component-based modulation strategies alone are usually not effective in solving all issues. Herein, we rationalized the facile construction of N, S co-doped Sb and carbon nanofibers (Sb@N,S-CNFs) with longitudinal tunnels through a tetrafunctional template-assisted strategy, taking into account the overall structural and compositional considerations. The pyrolysis of Sb2S3 nanorod template and the volatilization of Sb results in the formation of void space and Sb nanorods in longitudinal tunnels as well as the doping of Sb nanodots and sulfur in carbon fiber matrix. This well-designed multilevel structure optimized for favorable annealing time not only effectively mitigates large volume changes, but also greatly improves the diffusion kinetics of ions and electrons, thus resulting in much improved rate performance (219 mAh g−1 at 4 A g−1) and cycling stability (85.1% capacity retention after 1000 cycles at 2 A g−1) in half cells as well as a favorable rate capability and cycling performance in full cells matched with Na3V2(PO4)2O2F cathode. Additionally, the multifunctional template-assisted strategy provides precious guidance for the rational design and construction of high-performance electrode materials.

Oriented Catalytic Oxidation Induced Fabrication of CuO/Mn3O4 Hierarchical Arrays as Binder‐Free Electrodes for High‐Performance Supercapacitor

AbstractHerein, the authors report the fabrication of copper oxide/manganese oxide (CuO/Mn3O4) hierarchical arrays on Cu substrate via an oriented catalytic oxidation combined with subsequent annealing. Based on an ingenious oriented catalytic oxidation process, abundant CuO/Mn3O4 nanosheets are directionally modified on the surface of Cu(OH)2 nanorod arrays which are uniformly grown on the Cu substrate. Through subsequent annealing treatment in an N2 atmosphere, CuO/Mn3O4 nanorod arrays are fabricated with tuned oxygen vacancies. The 3D hybrid nanoarray structure with advantages of enhanced electron transfer, a large exposed surface area, and robust structure stability can address the drawbacks associated with bare CuO electrodes. As a result, the as‐prepared CuO/Mn3O4 nanoarray electrode demonstrates excellent electrochemical performance, delivering a high specific capacitance of 433 mF cm−2 at 5 mA cm−2 (1732 F g−1 at 20 A g−1), and achieving a long cycling lifespan with 144% capacitance retention at 20 mA cm−2 after 20 000 cycles. Interestingly, this facile oriented catalytic oxidation strategy can be extended to prepare other metal oxides/hydroxides (Ni2+, Co2+, Cu2+, Zn2+, or mixed ions based) on the surface of Cu(OH)2 nanorod templates respectively, manifesting its versatility for preparing CuO‐based hybrid nanorod arrays on the Cu substrate.

在水系锌电池中通过孔相双调控实现碳纳米管@硒化镍的快速动力学活化

Metal chalcogenide compounds can be used as high-performance cathodes for aqueous Zn batteries. However, the low accessible surfaces and violent volumetric expansion limit their properties and applications. To address these, phase-engineering strategies coupled with a hollow structure were applied to regulate the adsorption/desorption of OH− on the electrode surface and enhance the electrochemical performance. In this study, using a Se@C nanorod template, a series of carbon nanotube (CNT)-supported nickel selenides, including cubic NiSe2, NiSe2/Ni0.85Se composites, and hexagonal Ni0.85Se, were synthesized through an in situ selenylation process for the first time. Due to the large specific surface, high porosity, and hollow carbon skeleton, the optimized NiSe2/Ni0.85Se/CNT has a high specific capacity of 616 Cg−1, excellent rate capability, and stable cycling performance. In addition, its inside Faradic mechanism was investigated using a series of ex situ characterizations and density functional theory calculations. Thus, the fabricated Ni//Zn battery presents a high energy density of 311.4 W h kg−1 at 3485 W kg−1 and long cycling life. This study offers an ingenious strategy for designing nickel selenide electrodes and deeper perception for its Faradic mechanism in alkaline Zn battery.

Binary Cu2-xS Templates Direct the Formation of Quaternary Cu2ZnSnS4 (Kesterite, Wurtzite) Nanocrystals.

Kesterite Cu2ZnSnS4 (k-CZTS) nanocrystals have received attention for their tunable optoelectronic properties, as well as the earth abundance of their constituent atoms. However, the phase-pure synthesis of these quaternary NCs is challenging due to their polymorphism, as well as the undesired formation of related binary and ternary impurities. A general synthetic route to tackle this complexity is to pass through intermediate template nanocrystals that direct subsequent cation exchange toward the desired quaternary crystalline phase, particularly those that are thermodynamically disfavored or otherwise synthetically challenging. Here, working within this model multinary system, we achieve control over the formation of three binary copper sulfide polymorphs, cubic digenite (Cu1.8S), hexagonal covellite (CuS), and monoclinic djurleite (Cu1.94S). Controlled experiments with Cu0 seeds show that selected binary phases can be favored by the identity and stoichiometry of the sulfur precursor alone under otherwise comparable reaction conditions. We then demonstrate that the nature of the Cu2-xS template dictates the final polymorph of the CZTS nanocrystal products. Through digenite, the cation exchange reaction readily yields the k-CZTS phase due to its highly similar anion sublattice. Covellite nanocrystals template the k-CZTS phase but via major structural rearrangement to digenite that requires elevated temperatures in the absence of a strong reducing agent. In contrast, we show that independently synthesized djurleite nanorods template the formation of the wurtzite polymorph (w-CZTS) but with prominent stacking faults in the final product. Applying this refined understanding to the standard one-pot syntheses of k- and w-CZTS nanocrystals, we identify that these reactions are each effectively templated by binary intermediates formed in situ, harnessing their properties to guide the overall synthesis of phase-pure quaternary materials. Our results provide tools for the careful development of tailored nanocrystal syntheses in complex polymorphic systems.

Boosting photoresposive ability of WO3–Bi2O3 nanocomposite rods via annealing-induced intrinsic precipitation of nanosized Bi particles

In this study, Bi-particle-functionalized tungsten trioxide–bismuth oxide (WO3–Bi2O3) composite nanorods were prepared by integrating sputtering and hydrothermal syntheses with an appropriate postannealing procedure to induce Bi particle precipitation. Unlike other routes in which metal particle decoration is achieved externally, in this study, photoresponsive one-dimensional WO3–Bi2O3 composite nanorods were decorated with Bi particles by using the internal precipitation method. Structural analysis revealed that the Bi-metal-particle-functionalized WO3–Bi2O3 composite nanorods with particle size ranging from 5 to 10 nm were formed through hydrogen gas annealing at an optimal annealing temperature of 350 °C. Compared with the pristine WO3 nanorod template, the Bi–WO3–Bi2O3 composite nanorods exhibited higher photoresponsive performance, substantial photogenerated charge transfer ability, and efficient separation of photogenerated electron–hole pairs. The study results indicated that the Bi–WO3–Bi2O3 composite nanorods had superior decontamination ability and excellent stability toward RhB dye as compared with pristine WO3. Moreover, the photogenerated charge separation and migration efficiencies of the WO3–Bi2O3 nanorods could be tuned through appropriate reduction of the surface oxide layer; this is a promising approach to designing WO3–Bi2O3 nanorods with high photoactive performance.

Edge-exposed WS2 on 1D nanostructures for highly selective NO2 sensor at room temperature

• A highly effective strategy to expose numerous edge sites of WS 2 for chemoresistive gas sensor applications. • Extremely high gas response and excellent recovery characteristics achieved by WS 2 -based gas sensors at room temperature. • Interpretation of extremely high NO 2 selectivity achieved by edge-exposed WS 2 through DFT calculation. One of the well-known pathways toward low power consuming chemoresistive gas sensors is the utilization of 2-dimensional materials. Especially, transition metal dichalcogenides (TMDs), which are usually atomically thin semiconductors, have a notable characteristic of their highly reactive edge sites. The edge sites of TMDs having high d -orbital electron density can serve as highly favorable chemically active sites for direct interaction with target gas molecules. In this study, WS 2 was synthesized on highly porous SiO 2 nanorods template to have numerous edge-exposed WS 2 flakes in a limited active area taking advantage of 1-dimensional nanostructures with extremely high surface-to-volume ratio. The fabricated WS 2 on 1D nanostructures exhibited a gas response of 151.2 % toward 5 ppm NO 2 , which has not been reported in performance-wise at room temperature to the best of the author’s knowledge. Density functional theory calculations theoretically supported the highly sensitive and selective NO 2 detection with a theoretical detection limit of 13.726 ppb.

High-performance ordered porous Polypyrrole/ZnO films with improved specific capacitance for supercapacitors

Ordered porous polypyrrole/ZnO (PPy/ZnO) nanocomposites were synthesized on a fluorine tin oxide (FTO) substrate using an independent ZnO nanorod array template-assisted electrodeposition and template removal process with a pore size between 100 nm and 200 nm. The ordered porous structure of PPy/ZnO was verified by scanning electronmicroscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). The specific capacitance of porous PPy/ZnO nanocomposites can be as high as 161.02 F g−1, which is far higher than pure PPy (100.17 F g−1) at 1 M KCl aqueous solution with a current density of 0.5 A g−1. The improvement of specific capacitance performance is not only ascribe to the exposure of more active sites to obtain larger specific surface area, but also because of the synergistic effect between conductive PPy and ZnO, which shorten the electron transport channel, enhance the transmission efficiency of electrons in the entire electrode, and consequently result in a faster electron transfer. The specific capacitance of the porous PPy/ZnO nanocomposites retains 70.71% after 5000 cycles of charge/discharge, exhibiting good electrochemical cycle stability, which provides a potential as high-performing electrode material in supercapacitors.

Nonrecurring Circuit Nanozymatic Enhancement of Hypoxic Pancreatic Cancer Phototherapy Using Speckled Ru-Te Hollow Nanorods.

Nanozymatic reactions that produce or consume oxygen (O2) or reactive oxygen species (ROS) consist of oxidase, peroxidase, superoxide dismutase (SOD), and catalase-type activity. Although extensive studies were conducted to overcome hypoxia through nanozymatic reactions, the construction of an ideal system is challenging, given that the reactants and products are arranged in a recurring structure for continuous consumption in a full cycle. In this study, speckled Ru-Te hollow nanorods were prepared through solvothermal galvanic replacement against Te nanorod templates with high yield and robustness. From their multicompositional characteristics, nonrecurring peroxidase-SOD-catalase-type nanozymatic properties were identified with photothermal and photodynamic feasibility over a wide range of laser irradiation wavelengths. Owing to the excellent colloidal stability and biocompatibility, the proposed Ru-Te-based nanozymatic platform was highly effective in hypoxic pancreatic cancer phototherapy in vitro and in vivo by near-infrared laser irradiation mediated photothermal and photodynamic combination treatment.

Preparation of monodisperse SiO2 nanorods with hollow structure and parameters affecting the length-diameter ratio

Monodisperse SiO2 nanorods with hollow structure were prepared using FeOOH as a template. Powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption isotherms were utilized to characterize the products. With a FeCl3 concentration of 0.1 M, the average length and width of the prepared hollow SiO2 nanorods were 397 nm and 116 nm, respectively, and the average length-diameter ratio was calculated as 3.4. The average size of the nanopores of the amorphous SiO2 shell were measured as 2.5 nm. Furthermore, increasing the concentration of Cl− ions improved length-diameter ratios of the FeOOH nanorod template and hollow SiO2 nanorods.

Gas-assisted transformation of gold from fcc to the metastable 4H phase

The metastable hexagonal 4H-phase gold has recently attracted extensive interest due to its exceptional performance in catalysis. However, gold usually crystallizes to its lowest free energy structure called face-centered cubic (fcc). The phase transformation from the stable fcc phase to the metastable 4H phase is thus of great significance in crystal phase engineering. Herein, we report this unusual phenomenon on a 4H gold nanorod template with the aid of CO gas and an electron beam. In situ transmission electron microscopy was used to directly visualize the interface propagation kinetics between the 4H-Au-nanorod and fcc-Au nanoparticle. Epitaxial growth was initiated at the contact interface, and then propagated to convert all parts of these fcc nanoparticles to 4H phase. Density functional theory calculations and ab initio molecular dynamics simulations show that the CO molecules can assist the Au diffusion process and promote the flexibility of Au particles during the epitaxial growth. The phase transformation was driven by the reduction of Gibbs free energy by eliminating the interface between fcc and 4H phases.

Morphology-dependent photocatalytic and gas-sensing functions of three-dimensional TiO2–ZnO nanoarchitectures

Nanocomposites consisting of three-dimensional ZnO nanorods-decorated TiO2 nanorod templates (TiO2–ZnO) have been prepared by combining sputtering and hydrothermal growth strategies.

Smartphone-Based Point-of-Care Microfluidic Platform Fabricated with a ZnO Nanorod Template for Colorimetric Virus Detection

Viruses pose serious infectious disease threats to humans and animals. To significantly decrease the mortality and morbidity caused by virus infections, there is an urgent need of sensitive and rapid point-of-care platforms for virus detection, especially in low-resource settings. Herein, we developed a smartphone-based point-of-care platform for highly sensitive and selective detection of the avian influenza virus based on nanomaterial-enabled colorimetric detection. The 3D nanostructures, which serve as a scaffold for antibody conjugation to capture the avian influenza virus, are made on PDMS herringbone structures with a ZnO nanorod template. After virus capture, the on-chip gold nanoparticle-based colorimetric reaction allows virus detection by naked eyes with a detection limit of 2.7 × 104 EID50/mL, which is one order of magnitude better than that of conventional fluorescence-based ELISA. Furthermore, a smartphone imaging system with data processing capability further improves the detection limit, reaching down to 8 × 103 EID50/mL. The entire virus capture and detection process can be completed in 1.5 h. We envision that this point-of-care microfluidic system integrated with smartphone imaging and colorimetric detection would provide a fast, cheap, sensitive, and user-friendly platform for virus detection in low-resource settings.

Sputtering control of Ag2O decoration configurations on ZnO nanorods and their surface arrangement effects on photodegradation ability toward methyl orange

In this study, a combinational strategy for synthesizing ZnO nanorod arrays interlaced with Ag2O particles was proposed. Hydrothermally derived ZnO nanorod templates were sputter coated with Ag2O particles. The sputtered Ag2O particles can be decorated on the surfaces of the ZnO nanorod arrays with a randomly dispersive or continuous coverage characteristic by controlling the sputtering duration. Structural analysis revealed the formation of satisfactory crystalline ZnO–Ag2O composite nanorods through the hydrothermal and sputtering methods. The ZnO–Ag2O composite nanorods exhibited a significantly enhanced photoactivity compared with that of pristine ZnO nanorods under light irradiation. Moreover, the Ag2O content and the coverage feature of the ZnO–Ag2O composite nanorods influence the photodegradation of methyl orange solution by the composite nanorods under light irradiation. The photodegradation efficiency of the ZnO nanorods was substantially enhanced when the Ag2O particles were decorated on the surfaces in a dispersive manner. This can be attributed to the optimal content of Ag2O particles and their randomly dispersive characteristic on the surface of the composite nanorods, which resulted in the efficient transfer of photocarriers and markedly suppressed the electron–hole recombination rate.