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.

Template-Assisted Electrochemical Synthesis of CdSe Quantum Dots—Polypyrrole Composite Nanorods

Luminescent nanoparticles have reached a high level of maturity in materials and spectral tunability for optics and optoelectronics. However, the lack of facile methodology for heterojunction formation of the nanoparticles provides many challenges for scalability. In this paper we demonstrate a simple procedure to synthesize a nanoparticle-embedded polymer nanorod hybrid structure via a template-based electrochemical method using anodic aluminum oxide membranes. This method enables the formation of interactive nanostructures wherein the interface area between the two components is maximized. As a proof of concept, semiconducting CdSe nanoparticles were embedded in polypyrrole nanorods with dimensions that can be finely tuned. We observed enhanced photoluminescence of the hybrid structures compared with bare polypyrrole nanorods.

Facile Synthesis of Core-Shell Structured SiO2@Carbon Composite Nanorods for High-Performance Lithium-Ion Batteries

Recently, SiO2 has attracted wide attention in lithium-ion batteries owing to its high theoretical capacity and low cost. However, the utilization of SiO2 is impeded by the enormous volume expansion and low electric conductivity. Although constructing SiO2/carbon composite can significantly enhance the electrochemical performance, the skillful preparation of the well-defined SiO2/carbon composite is still a remaining challenge. Here, a facile strategy of in situ coating of polydopamine is applied to synthesis of a series of core-shell structured SiO2@carbon composite nanorods with different thicknesses of carbon shells. The carbon shell uniformly coated on the surface of SiO2 nanorods significantly suppresses the volume expansion to some extent, as well as improves the electric conductivity of SiO2. Therefore, the composite nanorods exhibit a remarkable electrochemical performance as the electrode materials of lithium-ion batteries. For instance, a high and stable reversible capacity at a current density of 100 mA g−1 reaches 690 mAh g−1 and a capacity of 344.9 mAh g−1 can be achieved even at the high current density of 1000 mA g−1. In addition, excellent capacity retention reaches 95% over 100 cycles. These SiO2@carbon composite nanorods with decent electrochemical performances hold great potential for applications in lithium-ion batteries.

Polyaniline/Al Bismuthate Composite Nanorods Modified Glassy Carbon Electrode for the Detection of Benzoic Acid

Context: Benzoic acid is a kind of extensively used preservative. It is of great significance to detect benzoic acid by a rapid method for quality assurance and protection in the fields of pharmaceutical, food and chemistry industry. Objective: The present research is aimed to prepare polyaniline/Al bismuthate composite nanorods by an in-situ polymerizing process for effective detection of benzoic acid. Methods: The polyaniline/Al bismuthate composite nanorods are prepared by an in-situ polymerizing process. The structure, morphology and electrochemical performance of the obtained polyaniline/Al bismuthate composite nanorods are analyzed by X-ray diffraction (XRD), transmission electron microscopy and electrochemical measurement. Results: XRD and transmission electron microscopy observations show that the amorphous nanoscale polyaniline particles attach to the surface of the crystalline nanorods. The electrochemical measurement of 2 mM benzoic acid using the composite nanorods modified glassy carbon electrode (GCE) shows that a pair of semi-reversible CV peaks is located at -0.11 V (cvp1) and -0.48 V (cvp1′), respectively. The electrochemical responses of 2 mM benzoic acid at the composite nanorods modified GCE are enhanced with increasing the scan rate and benzoic acid concentration. The polyaniline/Al bismuthate composite nanorods modified GCE shows a linear range of 0.001-2 mM with the limit of detection (LOD) of 0.18 µM. Conclusion: The composite nanorods may be used as the electrode materials with good reproducibility and stability for the detection of benzoic acid.