Controllable Synthesis of Iron Sulfide/CNT Nanocomposites in Solvothermal System

A Comparative Study of the Influence of Nitrogen Content and Structural Characteristics of NiS/Nitrogen-Doped Carbon Nanocomposites on Capacitive Performances in Alkaline Medium

Supercapacitors (SCs) have been regarded as alternative electrochemical energy storage devices; however, optimizing the electrode materials to further enhance their specific energy and retain their rate capability is highly essential. Herein, the influence of nitrogen content and structural characteristics (i.e., porous and non-porous) of the NiS/nitrogen-doped carbon nanocomposites on their electrochemical performances in an alkaline electrolyte is explored. Due to their distinctive surface and the structural features of the porous carbon (A-PVP-NC), the as-synthesized NiS/A-PVP-NC nanocomposites not only reveal a high wettability with 6 M KOH electrolyte and less polarization but also exhibit remarkable rate capability (101 C/g at 1 A/g and 74 C/g at 10 A/g). Although non-porous carbon (PI-NC) possesses more nitrogen content than the A-PVP-NC, the specific capacity output from the latter at 10 A/g is 3.7 times higher than that of the NiS/PI-NC. Consequently, our findings suggest that the surface nature and porous architectures that exist in carbon materials would be significant factors affecting the electrochemical behavior of electrode materials compared to nitrogen content.

A facile one step solvothermal controllable synthesis of FeS2 quantum dots with multiple color emission for the visual detection of aconitine

Iron disulfide (FeS₂) quantum dots have potential applications in various fields such as photocatalysis, lithium-ion batteries and bioimaging. At present, there is no report on the fluorescent characteristics of FeS₂ quantum dots (FeS₂ QDs). In this work, a synthesis of multiple-color emission FeS₂ QDs by changing the temperature, time and raw ratio has been reported. The blue, green, yellow and red emission FeS₂ QDs can be obtained, respectively. They were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). On this basis, a novel molecular imprinting ratiometric fluorescence sensor (MIR sensor) had been constructed, in which the blue-emission FeS₂ QDs (b-FeS₂ QDs) was used as a fluorescent responsive signal material and the yellow-emission FeS₂ QDs (y-FeS₂ QDs) was served as a reference signal material. And this MIR sensor was applied for highly selective and sensitive detection of ACO in traditional Chinese medicine (TCM). Under the optimum conditions, the MIR sensor exhibited an excellent linear relationship between the fluorescence intensity ratio (I₄₄₃/I₅₉₀) and the concentration of ACO in the range of 0.05-5.0 μM with a detection limit of 24 nM. Furthermore, the established method was successfully utilized to the detection of ACO in TCM Fuzi Lizhong Pills with satisfactory results. It provided a reference for the application of the FeS₂ QDs with multiple color emission and the detection of the hazardous alkaloids.