Composite Nanorods Research Articles

All‐Inorganic CsPbBr3/Cs4PbBr6 Perovskite/ZnO for Detection of NO with Enhanced Response and Low‐Work Temperature

AbstractHigh‐sensitive detection of NO is very important to protect environment and human health. In this study, the composites of ZnO nanorods and CsPbBr3/Cs4PbBr6 particles are synthesized successfully and used as sensing materials for detection of NO, in which the as‐prepared samples exhibit ultra‐high response and excellent selectivity to NO at 50 °C. Toward 100 ppm NO, the response is up to about 2296. The samples can high‐sensitively detect 1 ppm NO with response of about 6, demonstrating a low detection limit. The high response of CsPbBr3/Cs4PbBr6/ZnO could be attributed to the multiple heterojunctions formed among three materials. The results demonstrated that the composites of CsPbBr3/Cs4PbBr6 and ZnO should be a promising material for preparing the high‐sensitive NO sensors at low temperature.

Multifunctional palygorskite@ZnO nanorods enhance simultaneously mechanical strength and antibacterial properties of chitosan-based film

A general and effective strategy was developed for improving simultaneously the mechanical strength and antibacterial performance of biopolymer-based films. The well-dispersed zinc oxide (ZnO) nanoparticles were in-situ loaded on non-toxic natural palygorskite (PAL) nanorod to form an antibacterial PAL@ZnO composite nanorod, which can be embedded into chitosan/gelatin (CS/GL) film to produce the composite films with noticeably enhanced mechanical properties and antibacterial activity against S. aureus and E. coli bacteria (inhibition zones are 21.82 ± 0.95 mm and 16.36 ± 1.64 mm, respectively). The toughness of films enhances to 35.13 ± 0.95 MPa and the moisture uptake decreases to 23.74 ± 0.02% after embedding 3% and 9% of PAL@ZnO, respectively. In addition, incorporating PAL@ZnO nanorods also significantly enhanced the water resistance, and thermal stability of film. This work provides an alternative way for the development of antibacterial films with potential applications in many fields such as food packing.

A comparative study between two novel silicone/graphene-based nanostructured surfaces for maritime antifouling

Two novel superhydrophobic nanocomposite series of polydimethylsiloxane (PDMS) enriched with reduced graphene oxide (RGO) and graphene oxide/boehmite nanorods (GO-γ-AlOOH) nanofillers were synthesized as maritime fouling-release (FR) surfaces. Controlling the nanofillers' structures and distribution in the silicone matrix influenced the self-cleaning and antifouling properties. γ-AlOOH nanorods had a single crystallinity with an average diameter of 10–20 nm and < 200 nm length. A hydrothermal method was used to prepare RGO, while the chemical deposition method was used to synthesis GO-γ-AlOOH nanocomposites for use as fouling-release coating materials. For studying the synergetic effects of graphene-based materials on the surface, mechanical, and FR features, these nanofillers were dispersed in the silicone matrix using the solution casting method. The hydrophobicity and antifouling properties of the surface were studied using water contact angle (WCA), scanning electron, and atomic force microscopes (SEM and AFM). Coatings' roughness, superhydrophobicity, and surface mechanical properties all improved for the homogeneity of the dispersion of the nanocomposite. Laboratory assessments were carried out for 30 days using selected microorganisms to determine the antifouling effects of the coating systems. PDMS/GO-γ-AlOOH nanorod composite had better antibacterial activity than PDMS/RGO nanocomposite against different bacterial strains. This is caused by the high surface area and stabilizing effects of the GO-γ-AlOOH hybrid nanofillers. The PDMS/GO-γ-AlOOH nanorod composite (3 wt%) had the lowest biodegradability percentage (1.6%) and the microbial endurability percentages for gram-positive, gram-negative, and fungi were 86.42%, 97.94%, and 85.97%, respectively. A field trial in natural seawater was conducted to confirm the coatings' FR performance based on the screening process and image analysis for 45 days in a tropical area. The most profound superhydrophobic antifouling nanostructured coating was the homogeneity of the GO-γ-AlOOH (3 wt%) dispersion, which had a WCA of 151° and a rough surface.

Detection of accumulated continuously ethanol concentration by ZnO–SnO2 composite nanorods sensor

ZnO–SnO2 composite nanorods with rough surfaces were synthesized via a coaxially nested needle electrospinning method. The morphology and nanostructure were characterized by scanning electron microscopy, atomic force microscope, EDS mapping, nitrogen physical adsorption, and X-ray diffraction. The synthesis mechanisms of ZnO–SnO2 nanorods were discussed, which combined the gas sensitivity advantages of different materials. ZnO–SnO2 nanorods sensor with good ethanol gas sensitivity achieved accurate measurement of continuous ethanol concentration. The sensor exhibited good selectivity to ethanol in the presence of formaldehyde, methanol, acetone, acetic acid, benzene, and xylene at 290[Formula: see text]C. The response and recovery time to 100 ppm ethanol were about 13 and 35 s, respectively. The energy band, barrier, charge transfer of ZnO–SnO2 composite material was discussed, and its optimization of gas sensitivity was analyzed in detail.

Self-powered adjustable UV and NIR photodetectors based on one-step synthesized TeO2 doped ZnO composite nanorods/Si heterojunction

Tellurium dioxide (TeO2) doped zinc oxide (ZnO) composite nanorods (TZO CNRs) were first synthesized by chemical vapor deposition method on a p-type silicon substrate covered by a sputtered gold (Au) film. The morphologies, structures, compositions and optical properties of the TZO CNRs can be modulated with the TeO2 content. Three typical self-powered TZO CNRs/Si heterojunction photodetectors named device 1, 2 and 3 according to the different TeO2 contents and TZO CNR morphologies are designed. Device 1 based on 1.81 At% Te content TZO CNRs can detect UV lights with wavelength from 290 to 380 nm and showed a responsivity of 4.3 mA/W, a detectivity of 1.1 × 1012 cmHz1/2W−1 upon exposure to 370 nm light at a zero-bias voltage. Device 2 based on 5.86 At% Te content TZO CNRs is found to be selectively sensitive to UV and NIR lights. Device 3 based on 9.23 At% Te content TZO CNRs is found to be also selectively sensitive to NIR lights. Its most sensitive wavelength is 1040 nm with responsivity and detectivity of 24.6 mA/W and 4.12 × 1012 cmHz1/2W−1, respectively. In addition, the mechanism that led to their typical properties of these devices are also elucidated.

Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution under mild conditions of light irradiation is considered as one of the most efficient and promising approach to obtain high purity hydrogen and value-added chemicals concurrently by utilizing green solar energy. Here, we report the synthesis of NiS nanoparticle-modified CdS nanorod composites (NiS/CdS) as an efficient bifunctional catalyst for the highly selective photocatalytic synthesis of high-value-added product benzaldehyde (BAD) from aqueous solution of benzyl alcohol (BA) under oxygen-free conditions, in accompanying with the efficient hydrogen evolution. The synergetic catalytic effect between NiS and CdS is proposed to play an important role in elevating the photo-redox performance. The composition-optimized 30% NiS/CdS catalyst affords an extraordinarily high H2 generation rate of 207.8 μmol h−1 and a simultaneous BAD generation rate of 163.8 μmol h−1 under visible light irradiation, which are respectively 139 and 950 times higher than those of CdS without NiS modification. To our knowledge, these are the highest photocatalytic production rates of both H2 and aldehyde ever reported on the concurrent photocatalytic of aldehyde synthesis and hydrogen evolution in green aqueous solution. This work provides a highly efficient photosynthesis strategy for the concurrent productions of high-value-added fine chemicals and hydrogen.

Interfacial Engineering of CuCo2S4/g-C3N4 Hybrid Nanorods for Efficient Oxygen Evolution Reaction.

Altering the morphology of electrochemically active nanostructured materials could fundamentally influence their subsequent catalytic as well as oxygen evolution reaction (OER) performance. Enhanced OER activity for mixed-metal spinel-type sulfide (CuCo2S4) nanorods is generally done by blending the material that has high conductive supports together with those having a high surface volume ratio, for example, graphitic carbon nitrides (g-C3N4). Here, we report a noble-metal-free CuCo2S4 nanorod-based electrocatalyst appropriate for basic OER and neutral media, through a simple one-step thermal decomposition approach from its molecular precursors pyrrolidine dithiocarbamate-copper(II), Cu[PDTC]2, and pyrrolidine dithiocarbamate-cobalt(II), Co[PDTC]2 complexes. Transmission electron microscopy (TEM) images as well as X-ray diffraction (XRD) patterns suggest that as-synthesized CuCo2S4 nanorods are highly crystalline in nature and are connected on the g-C3N4 support. Attenuated total reflectance-Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy studies affirm the successful formation of bonds that bridge (Co-N/S-C) at the interface of CuCo2S4 nanorods and g-C3N4. The kinetics of the reaction are expedited, as these bridging bonds function as an electron transport chain, empowering OER electrocatalytically under a low overpotential (242 mV) of a current density at 10 mA cm-2 under basic conditions, resulting in very high durability. Moreover, CuCo2S4/g-C3N4 composite nanorods exhibit a high catalytic activity of OER under a neutral medium at an overpotential of 406 mV and a current density of 10 mA cm-2.

Construction of Carbon-Coated LiMn0.5Fe0.5PO4@Li0.33La0.56TiO3 Nanorod Composites for High-Performance Li-Ion Batteries.

The carbon-coated LiMn0.5Fe0.5PO4@Li0.33La0.56TiO3 nanorod composites (denoted as C/LMFP@LLTO) have been successfully obtained according to a common hydrothermal synthesis following a post-calcination treatment. The morphology and particle size of LiMn0.5Fe0.5PO4 (denoted as LMFP) are not changed by the coating. All electrode materials exhibit nanorod morphology; they are 100-200 nm in length and 50-100 nm in width. The Li0.33La0.56TiO3 (denoted as LLTO) coating can facilitate the charge transfer to enhance lithiation/delithiation kinetics, leading to an excellent rate performance and cycle stability of an as-obtained C/LMFP@LLTO electrode material. The reversible discharge capacities of C/LMFP@LLTO (3 wt %) at 0.05 and 5 C are 146 and 131.3 mA h g-1, respectively. After 100 cycles, C/LMFP@LLTO (3 wt %) exhibits an outstanding capacity of 106.4 mA h g-1 with an 81% capacity retention rate at 5 C, indicating an excellent reversible capacity and good cycle capacity. Therefore, it can be considered that LLTO coating is a prospective pathway to exploit the electrochemical performances of C/LMFP.

Highly efficient photocatalytic degradation of chlorpyrifos in aqueous solutions by nano hydroxyapatite modified CFGO/ZnO nanorod composite

A visible-light-driven photocatalyst, nanohydroxy apatite decorated carboxyl functionalized graphene oxide/zinc oxide nanorod (nHAP@CFGO/ZnR) composite was prepared and well characterized by FTIR, XRD, SEM/EDS, HRTEM, XPS, AFM, Raman, DRS, Surface area analyser, PL and EIS. nHAP@CFGO/ZnR composite exhibited high photoactivity and photostability to degrade the pesticide, chlorpyrifos (CP) in aqueous solutions under visible light. The band gap of the prepared photocatalyst was found to be 2.8 eV which is in the visible region. The maximum adsorption occurs at pH 3.5. The adsorption kinetic and isotherm data were described using pseudo-second-order kinetic model and Sips isotherm model, respectively. The photocatalytic degradation of CP was found to follow first-order kinetics and optimum pH for degradation was found to be 3.0. The regeneration and recyclability of the photocatalyst was examined upto five cycles that confirmed the relative stability of the photocatalyst.

Reduced Graphene Oxide/WO3 Nanorod Composites for Photocatalytic Degradation of Methylene Blue under Sunlight Irradiation

Reduced Graphene Oxide/WO₃ Nanorod Composites for Photocatalytic Degradation of Methylene Blue under Sunlight Irradiation

Synthesis of high-performance nickel hydroxide nanosheets/gadolinium doped-α-MnO2 composite nanorods as cathode and Fe3O4/GO nanospheres as anode for an all-solid-state asymmetric supercapacitor

The wide use of manganese dioxide (MnO2) as an electrode in all-solid-state asymmetric supercapacitors (ASCs) remains challenging because of its low electrical conductivity. This complication can be circumvented by introducing trivalent gadolinium (Gd) ions into the MnO2. Herein, we describe the successful hydrothermal synthesis of crystalline Gd-doped MnO2 nanorods with Ni(OH)2 nanosheets as cathode, which we combined with Fe3O4/GO nanospheres as anode for all-solid-state ASCs. Electrochemical tests demonstrate that Gd doping significantly affected the electrochemical activities of the MnO2, which was further enhanced by introducing Ni(OH)2. The GdMnO2/Ni(OH)2 electrode offers sufficient surface electrochemical activity and exhibits excellent specific capacity of 121.8 mA h g−1 at 1 A g−1, appealing rate performance, and ultralong lifetime stability (99.3% retention after 10,000 discharge tests). Furthermore, the GdMnO2/Ni(OH)2//PVA/KOH//Fe3O4/GO solid-state ASC device offers an impressive specific energy density (60.25 W h kg−1) at a high power density (2332 W kg−1). This investigation thus shows its large potential in developing novel approaches to energy storage devices.

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.

Single crystalline rutile TiO2 nanorods synthesis by onestep catalyst-free vapor transport method

In this report, a novel one-step approach to grow highly crystalline rutile TiO2 nanorods on bare silicon substrate by a simple vapor transport technique without a catalyst is discussed. The crystal structure of the nanorod ensemble was examined by X-ray diffraction. The structure and morphology of the nanorods were analyzed by scanning electron microscopy and transmission electron microscopy and the one dimensional growth direction was observed to be along (110) plane. Chemical composition of the individual nanorods was examined by X-ray energy-dispersive spectrometry. A possible growth mechanism for the nanorods has been proposed. As the synthesis was catalyst-free, the resulting nanorods were of high purity. These nanorods are expected to have a variety of applications.

The novel photo-Fenton-like few-layer MoS2/FeVO4 composite for improved degradation activity under visible light irradiation

Photo-Fenton degradation of pollutants is considered to be a feasible method for eliminating the environmental pollution. However, traditional photo-Fenton catalyst still possessed unsatisfactory photocatalytic performance attributed to low separation efficiency of photo-generated electron-hole pairs. Herein, novel MoS2/FeVO4 nanorods composites were synthesized successfully via ionic liquid 1-octyl-3-methylimidazolium chloride ([OMim]Cl) assisted hydrothermal process. Compared with pure FeVO4, the introduction of MoS2 not only enhanced visible light absorption capacity but also specific surface area effectively. Furthermore, the recombination efficiency of photo-induced electron-hole pairs of MoS2/FeVO4 composite was decreased greatly ascribed to the construction of heterojunction. Consequently, the MoS2/FeVO4 composites performed an enhanced Photo-Fenton catalytic activity for dye and antibiotic. The possible mechanism of MoS2/FeVO4 photo-Fenton degradation process was inferred based on a serious of characterizations and analysis. This work provided a new path to further expand the practical application of new-generation photo-Fenton-like catalysts.

Multiscale modelling of magnetostatic effects on magnetic nanoparticles with application to hyperthermia

We extend a renormalization group-based (RG) coarse-graining method for micromagnetic simulations to include properly scaled magnetostatic interactions. We apply the method in simulations of dynamic hysteresis loops at clinically relevant sweep rates and at 310 K of iron oxide nanoparticles (NPs) of the kind that have been used in preclinical studies of magnetic hyperthermia. The coarse-graining method, along with a time scaling involving sweep rate and Gilbert damping parameter, allow us to span length scales from the unit cell to NPs approximately 50 nm in diameter with reasonable simulation times. For both NPs and the nanorods composing them, we report effective uniaxial anisotropy strengths and saturation magnetizations, which differ from those of the bulk materials magnetite and maghemite of which they are made, on account of the combined non-trivial effects of temperature, inter-rod exchange, magnetostatic interactions and the degree of orientational order within the nanorod composites. The effective parameters allow treating the NPs as single macrospins, and we find for the test case of calculating loops for two aligned NPs that using the dipole approximation is sufficient for distances beyond 1.5 times the NP diameter. We also present a study on relating integration time step to micromagnetic cell size, finding that the optimal time step size scales approximately linearly with cell volume.

Remote Sensing and Remote Actuation via Silicone-Magnetic Nanorod Composites.

The capacity for a soft material to combine remote sensing and remote actuation is highly desirable for many applications in soft robotics and wearable technologies. This work presents a silicone elastomer with a suspension of a small weight fraction of ferromagnetic nickel nanorods, which is capable of both sensing deformation and altering stiffness in the presence of an external magnetic field. Cylinders composed of silicone elastomer and 1% by weight nickel nanorods experience large increases in compressive modulus when exposed to an external magnetic field. Incremental compressions totaling 600 g of force applied to the same silicone-nanorod composites increase the magnetic field strength measured by a Hall effect sensor enabling the material to be used as a soft load cell capable of detecting the rate, duration, and magnitude of force applied. In addition, lattice structures are 3D printed using an ink composed of silicone elastomer and 1% by weight nickel nanorods, which possess the same sensing capacity.

Photocatalytic reduction of uranium(VI) under visible light with 2D/1D Ti3C2/CdS

• Visible-light-driven photoreduction of U(VI) is achieved without any sacrificial agents. • Ti 3 C 2 in 2D/1D Ti 3 C 2 /CdS composites acts as a Janus co-catalyst. • A high U(VI) extraction capacity of 500 mg/g was obtained in 40 min. • The Ti 3 C 2 /CdS composites keep high performance in wide pH range. Herein, for the first time, the visible-light-driven 2D/1D Ti 3 C 2 /CdS nanorods composites were fabricated by electrostatic assembly strategy to achieve efficient uranium(VI) photoreduction without any sacrificial agents. While CdS is the main catalyst, Ti 3 C 2 in the composites acts as a Janus co-catalyst for the photoreduction of uranium(VI), in view of the fact that it can simultaneously enhance the photocatalytic performance and the stability of CdS. With the initial uranium(VI) concentration at 50 ppm, 97% uranium(VI) reduction efficiency was achieved by the optimal Ti 3 C 2 /CdS composites during 40 min visible light irradiation without any sacrificial agents. The kinetic reaction rate reaches as high as 1520 μmol/(g·h). Meanwhile, the Ti 3 C 2 /CdS composites keep high performance regardless of acidic, neutral and alkali conditions. The findings of this work highlight the vast opportunities for Ti 3 C 2 /CdS composites in the treatment of radioactive wastewater.

Phase behavior of polymer-nanorod composites: A comparative study using PRISM theory and molecular dynamics simulations.

Well-dispersed composites of polymer and nanorods have many emerging applications and, therefore, are an important area of research. Polymer reference interaction site model (PRISM) theory and molecular dynamics simulations have become powerful tools in the study of the structure and phase behavior of polymer nanocomposites. In this work, we employ both PRISM theory and molecular dynamics simulations to determine the structure and spinodal phase diagram of 1% volume fraction of nanorods in a polymer melt. We make quantitative comparisons between the phase diagrams, which are reported as a function of nanorod aspect ratio and polymer-nanorod interactions. We find that both PRISM theory and molecular dynamics simulations predict the formation of contact aggregates at low polymer-nanorod attraction strength (γ) and bridged aggregates at high polymer-nanorod attraction strength. They predict an entropic depletion-driven phase separation at low γ and a bridging-driven spinodal phase separation at high γ. The polymer and nanorods are found to form stable composites at intermediate values of the polymer-nanorod attraction strength. The fall of the bridging boundary and the gradual rise of the depletion boundary with the nanorod aspect ratio are predicted by both PRISM theory and molecular dynamics simulations. Hence, the miscible region narrows with increasing aspect ratio. The depletion boundaries predicted by theory and simulation are quite close. However, the respective bridging boundaries present a significant quantitative difference. Therefore, we find that theory and simulations qualitatively complement each other and display quantitative differences.

BSA-lysozyme coated NaCa2HSi3O9 nanorods on titanium for cytocompatibility and antibacterial activity

Extracellular supplement of Ca and Si accelerates osteogenisis and angiogenisis during bone repair. Ca-Si-based ceramics are biodegradable and can release Ca and Si ions efficiently. However, locally high alkalinity induced by excessively rapid degradation limits their application. In this paper, NaCa2HSi3O9 (NCS) nanorods were fabricated on Ti by micro-arc oxidation and hydrothermal treatment; protein layers consisted of different rations of bovine serum albumin (BSA) and lysozyme (LYS) were prepared on NCS nanorods by spinning coating and thermal stabilization. The microstructure, ion releasing and wettability of coatings were observed; osteoblast and endotheliocyte behaviors, as well as bacteria response in vitro, were evaluated. The protein layer did not change microstructure and phase composition of nanorods but acted as a barrier isolating nanorods from contacting medium, and it results in slowing down the degradation of nanorods. The reduced increase of pH value, released Ca and Si ions and incorporation of LYS in BSA protein layer gave NCS nanorods improved MC3T3-E1 and HUVECs response, compared with Ti. Meanwhile, the protein layers except pure LYS endowed nanorods with a highly antibacterial effect against staphylococcus aureus and escherichia coli simultaneously, indicating the key role of BSA in resisting antibacterial adhesion. NCS nanorods with BSA and LYS composited protein layers should be a potential coating applied on Ti implants for increasing osseointegration.

Evaluation of the Mechanical Properties of ZnO Nanorods Treated with Oxygen Plasma using Atomic Force Microscopy

Zinc oxide (ZnO) simultaneously exhibits semiconducting and piezoelectric properties. ZnO in the form of nanorods has been studied intensively for application in self-powering devices. The power generation in piezoelectric nanogenerators based on ZnO nanorods can be improved via several approaches, including an oxygen plasma treatment. When ZnO nanorods are exposed to oxygen plasma, the charge carrier concentration decreases and the piezoelectric output voltage consequently increases. However, the effects of oxygen plasma on the mechanical properties of ZnO nanorods has not been systematically studied using a precise measurement technique. Given the size of ZnO nanorods, atomic force microscopy (AFM) is a suitable method for manipulating individual ZnO nanorods and measuring their elastic properties. In the present work, we observed the effects of oxygen plasma on the elemental composition and microstructure of ZnO nanorods. First of all, the surface roughness of the ZnO nanorods was analyzed using AFM, revealing that it increased due to the etching effect of the oxygen plasma. From X-ray photoelectron spectroscopy (XPS) measurements, three distinct peaks corresponding to lattice oxygen, oxygen vacancies, and absorbed oxygen on the surface were identified. The XPS analysis results showed that oxygen vacancy defects on the ZnO nanorods were decreased by oxygen plasma treatment. Next, the effects of oxygen plasma on the elastic properties of ZnO nanorods were studied using lateral force microscopy. It was confirmed that the elastic modulus of ZnO nanorods increased due to the reduced number of defects originating from oxygen vacancies.