Graphitized porous carbon nanofibers were prepared by electrospinning and subsequent calcining, exhibiting high capacity and good cycling stability.

In this paper, ferroferric oxide (Fe 3 O 4 ) nanoparticles/porous carbon nanofibers 10 (Fe 3 O 4 /PCNFs) composites were successfully fabricated by elctrospinning and subsequent 11 calcinations. The composites were characterized by X-ray diffraction, thermogravimetric 12 analysis, scanning electron microscopy and transmission electron microscopy to analyze the 13 structure, composition and morphology. The electrochemical performance was evaluated by 14 coin-type cells versus metallic lithium. The results indicated that Fe 3 O 4 /PCNFs composites 15 exhibited high reversible capacity and good capacity retention. The discharge capacity 16 maintained 717.2 mA h g -1 at 0.5 A g -1 after 100 cycles. The excellent performances of 17 Fe 3 O 4 /PCNFs composites are attributed to good crystallinity and uniformly dispersive Fe 3 O 4 18 nanoparticles, and porous carbon shell with high conductivity. The carbon coating buffered 19 the tremendous volumetric changes between Fe 3 O 4 nanoparticles and Fe atoms in the 20 charge/discharge processes and kept the structure integrity of Fe 3 O 4 nanoparticles. Porous 21 carbon nanofibers prepared by unique calcination process improved the conductivity of 22 composites and provided free space for migration of lithium ions. The preparation of strategy 23 is expected to be applied to the preparation of other transition metal oxides materials as 24

Fe3O4/rGO nanocomposites were prepared by hydrothermal method using Fe(OH)3 as precursor of magnetite nanoparticles, graphene oxide (GO) as precursor of reduced graphene oxide (rGO), hydrazine and trisodium citrate as mixed reducing agent. The morphologies, structures and compositions of the products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The electrochemical characteristics of assembled coin-type cells versus metallic lithium were evaluated by cyclic voltammetry and galvanostatic charge-discharge. The uniform morphology, high reductive level of rGO and the role of rGO buffering the volume changes of Fe3O4 nanoparticles in the charging-discharging process can be responsible for the good electrochemical performance of Fe3O4/rGO nanocomposites.

Dopamine (DA) plays a crucial role in the functioning of the human central nervous system, participating in both physiological and psychological processes. It is an important research topic in biomedical science. However, we need to constantly monitor the concentration of dopamine in the body, and the sensors required for this usually require good sensitivity in order to achieve fast and accurate measurements. In this research project, a CeO2 and CuCrO2 composite nanofiber was prepared for the electrochemical detection of dopamine. Coaxial electrospinning techniques were used to prepare CeO2–CuCrO2 composite nanofibers. The characterization techniques of X-ray diffractometer (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) were used to analyze the composite’s crystal structure, vibrational bonds, and elemental composition, while SEM and TEM were used to analyze the composite’s surface structure, morphology, and microstructure. The prepared nanofiber outer layer was found to have an average thickness of 70.96 nm, average fiber diameter of 192.49 nm, and an average grain size of about ~12.5 nm. The BET analysis was applied to obtain the specific surface area (25.03 m2/gm). The proposed nanofiber-decorated disposable screen-printed carbon electrode acted as a better electrochemical sensor for the detection of dopamine. Moreover, the electrocatalyst had a better limit of detection, 36 nM with a linear range of 10 to 100 μM, and its sensitivity was 6.731 μA μM−1 cm−2. In addition, the proposed electrocatalyst was successfully applied to real-time potential applications, namely, to the analysis of human urine samples in order to obtain better recovery results.