Jilin University

About: Jilin University is a education organization based out in Changchun, China. It is known for research contribution in the topics: Catalysis & Apoptosis. The organization has 101453 authors who have published 88966 publications receiving 1444456 citations. The organization is also known as: Jílín Dàxué.

Porous Graphitic Carbon Nanosheets Derived from Cornstalk Biomass for Advanced Supercapacitors

Abstract: Porous graphitic carbon nanosheets (PGCS) are synthesized by an in situ self-generating template strategy based on the carburized effect of iron with cornstalks. Cornstalks firstly coordinate with [Fe(CN)(6)](4-) ions to form the cornstalk-[Fe(CN)(6)](4-) precursor. After carbonization and removal of the catalyst, PGCS are obtained. Series experiments indicate that PGCS can only be formed when using an iron-based catalyst that can generate a carburized phase during the pyrolytic process. The unique structures of PGCS exhibit excellent capacitive performance. The PGCS-1-1100 sample (synthesized from 0.1 M [Fe(CN)(6)](4-) with a carbonization temperature of 1100 °C), which shows excellent electrochemical capacitance (up to 213 F g(-1) at 1 A g(-1)), cycling stability, and rate performance in 6 M KOH electrolyte. In the two-electrode symmetric supercapacitors, the maximum energy densities that can be achieved are as high as 9.4 and 61.3 Wh kg(-1) in aqueous and organic electrolytes, respectively. Moreover, high energy densities of 8.3 and 40.6 Wh kg(-1) are achieved at the high power density of 10.5 kW kg(-1) in aqueous and organic electrolytes, respectively. This strategy holds great promise for preparing PGCS from natural resources, including cornstalks, as advanced electrodes in supercapacitors.

Improved selective acetone sensing properties of Co-doped ZnO nanofibers by electrospinning

Abstract: Pure and Co-doped (0.3 wt%, 0.5 wt%, and 1 wt%) ZnO nanofibers are synthesized by an electrospinning method and followed by calcination. The as-synthesized nanofibers are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) spectroscopy. Comparing with pure ZnO nanofibers, Co-doped nanofibers exhibit improved acetone sensing properties at 360 °C. The response of 0.5 wt% Co-doped ZnO nanofibers to 100 ppm acetone is about 16, which is 3.5 times larger than that of pure nanofibers (about 4.4). The response and recovery times of 0.5 wt% Co-doped ZnO nanofibers to 100 ppm acetone are about 6 and 4 s, respectively. Moreover, Co-doped ZnO nanofibers can successfully distinguish acetone and ethanol/methanol, even in a complicated ambience. The high response and quick response/recovery are based on the one-dimensional nanostructure of ZnO nanofibers combining with the Co-doping effect. The selectivity is explained by the different optimized operating temperatures of Co-doped ZnO nanofibers to different gases.

Controlled synthesis and morphology dependent upconversion luminescence of NaYF4 : Yb, Er nanocrystals

Abstract: Size and morphology controlled NaYF4:Yb, Er nanocrystals were synthesized via the hydrothermal method. Polydentate ligands, such as EDTA and citrate, were used in the synthesis of cubic and hexagonal Yb3+, Er3+ codoped NaYF4 nanocrystals as a means of controlling the size and morphology of the nanocrystals. Subsequently, the particle size was found to be dependent on the nucleation rate, which, in turn, was governed by the reactant concentration, molar ratio and choice of ligand. The phase transformation from cubic to hexagonal was found to be sensitive to reaction time and reactant concentration. The upconversion photoluminescence of the nanocrystals demonstrated morphology dependence, which provides a means to characterize their crystalline quality and structure.