Enyan Guo

Graphene membrane encapsulated Co3O4 nanotubes with superior capacity and stability as anode materials for lithium ion batteries

The electrospun Co3O4 nanotubes encapsulated by graphene membrane are successfully synthesized via a novel and efficient method. The Co3O4 nanotubes with the diameter of ~200 nm are prepared by electrospinning combined with sintering process. Graphene is wrapped on the charge-modified surface of Co3O4 nanotubes by the mutual electrostatic interactions. The as-prepared graphene/Co3O4 nanotubes are applied as anode materials for lithium-ion batteries and show the improved rate capacities (up to 430.9 mAh g−1 at the current density of 1600 mA g−1) and excellent rechargeable stability (961.4 mAh g−1 at the current density of 100 mA g−1 after 80 cycles). The existence of graphene membrane not only decreases the lithium ion transport path due to serving as the additional transport channel, but also provides the elastic buffer to avoid the agglomeration of the Co3O4 nanotubes. The nanotubes located in the graphene could effectively prevent the agglomeration of graphene membranes, and consequently keep their high active surface area. The complementary and synergistic effect of Co3O4 nanotubes and graphene makes a great contribution to the outstanding electrochemical properties.Graphical AbstractThe graphene/Co3O4 nanotubes composites were applied as anode materials and shown excellent electrochemical performance.

FeVO4 nanobelts: controllable synthesis by electrospinning and visible-light photocatalytic properties

In the present work, one-dimensional FeVO4 nanobelts with the width of about 400 nm have been successfully prepared by a simple electrospinning process followed by the subsequent calcination process. The prepared products are characterized by thermogravimetric and differential scanning calorimetric, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra, scanning electron microscopy, UV-vis absorbance spectroscopy, nitrogen adsorption-desorption isotherms and total organic carbon. The results indicated that the as-prepared FeVO4 nanobelts belonging to the triclinic crystal system presented the one-dimensional belts structure. In addition, the morphologies, crystallite size and surface area of FeVO4 nanobelts were distinctly affected by the calcination temperature. And the FeVO4 nanobelts calcined at 600 °C for 2 h owned an excellent photocatalytic properties for the degradation of rhodamine B solution under the visible light irradiation.Graphical abstractSchematic representation of electrospinning process and morphology evolution of FeVO4 nanobelts during calcination process.

ZnO/γ-Bi 2 MoO 6 heterostructured nanotubes: electrospinning fabrication and highly enhanced photoelectrocatalytic properties under visible-light irradiation

ZnO/γ-Bi2MoO6 heterostructured nanotubes consisting of external shell of ZnO and γ-Bi2MoO6 with the outer diameter of about 400–500 nm and wall thickness of around 90 nm have been successfully fabricated by a combination of electrospinning and calcination strategy and characterized by TG-DSC, FT-IR, SEM, XRD, TEM, HRTEM, UV–Vis DRS, PL spectra, EIS, and TOC analysis. The photocatalytic activities of resulting nanotubes are evaluated through the photodegradation of methylene blue (MB) and measurements of photocurrent (PC) under visible-light irradiation. The results reveal that ZnO/γ-Bi2MoO6 nanotubes possess the exceptional photocatalytic and recycling properties. The enhanced degradation performance could be attributed to the positive synergistic effect of the well-established ZnO/γ-Bi2MoO6 hererostructures in promoting the transfer and separation of photogenerated carriers.Graphical abstractSchematic diagram of electron-hole separation mechanism for ZnO/γ-Bi2MoO6 nanotubes.