Synthesis of Flower-Like Cu 2

Flower-like Cu2ZnSnS4 (CZTS) nanoflakes were synthesized by a facile and fast one-pot solution reaction using copper(II) acetate monohydrate, zinc acetate dihydrate, tin(IV) chloride pentahydrate, and thiourea as starting materials. The as-synthesized samples were characterized by X-ray diffraction (XRD), Raman scattering analysis, field emission scanning electron microscopy (FESEM) equipped with an energy dispersion X-ray spectrometer (EDS), transmission electron microscopy (TEM), and UV-Vis absorption spectra. The XRD patterns shown that the as-synthesized particles were kesterite CZTS and Raman scattering analysis and EDS confirmed that kesterite CZTS was the only phase of product. The results of FESEM and TEM show that the as-synthesized particles were flower-like morphology with the average size of 1~2 μm which are composed of 50 nm thick nanoflakes. UV-Vis absorption spectrum revealed CZTS nanoflakes with a direct band gap of 1.52 eV

Hydrothermal Synthesis of Al/Cr-doped V

Pure V6O13 and Al/Cr-doped V6O13 were synthesized via a hydrothermal route using C2H2O4·2H2O, V2O5, Al(NO3)3·9H2O and Cr(NO3)3·9H2O as raw materials. The products were characterized by XRD, SEM, EDS. Doping proven to be an effective method to improve the samples discharge specific capacity and cycle performance. Doping samples electrochemical performance were better than pure V6O13, the initial discharge specific capacity of sample 0.02 and 0.06 were 311mAh/g and 337mAh/g larger than pure V6O13 sample (241 mAh/g). The capacity retention of samples 0.00, 0.02, 0.06 was 32.0%, 44.69%, 28.78% after 100 cycles, respectively. The increased electrochemical performance originated from the enhanced of electrical conductivity and adhered together by stacking region in an regular arrangement with every unit

The Preparation of VO

Fiber-like VO2(B) was successfully synthesized by using V2O5 and ethanol as reactants via a magnetic stirring solvothermal process. The stirring rates significantly affected the phase, morphology and the cycling performance of as-synthesized products. When the stirring rate was 867 rpm, the fiber-like particles were 3–5 μm long and 50–100 nm wide, and showed better dispersion than the sample of VO-0, the electrochemical performance test demonstrated that the initial discharge capacity of VO-867 was 223 mAh/g, and maintained 186 mAh/g after cycling for 50 times, the retention rate of the capacity was 83.4%, which showed best cycling property of all samples

The Preparation of VO2(B) Cathode Material for Lithium-ion Battery with High Capacity and Good Cycling Performance

Fiber-like VO2(B) was successfully synthesized by using V2O5 and ethanol as reactants via a magnetic stirring solvothermal process. The stirring rates significantly affected the phase, morphology and the cycling performance of as-synthesized products. When the stirring rate was 867 rpm, the fiber-like particles were 3–5 μm long and 50–100 nm wide, and showed better dispersion than the sample of VO-0, the electrochemical performance test demonstrated that the initial discharge capacity of VO-867 was 223 mAh/g, and maintained 186 mAh/g after cycling for 50 times, the retention rate of the capacity was 83.4%, which showed best cycling property of all samples

Synthesis and Electrochemical Performance of Ni-Doped VO2(B) as a Cathode Material for Lithium Ion Batteries

Ni-doped VO2(B) samples (NixVO2(B)) were fabricated by a facile one-step hydrothermal method. When evaluated as a cathode material for lithium ion batteries (LIBs), these Ni-doped VO2(B) exhibited improved lithium storage performance as compared to the pure VO2(B). In particular, when the doping amount is 3%, NixVO2(B) showed the highest lithium storage capacity, best cycling stability, smallest electrochemical reaction resistance, and largest lithium diffusion coefficient. For example, after 100 cycles at a current density of 32.4 mA/g, NixVO2(B) delivered a high specific discharge capacity of 163.0 mAh/g, much higher than that of the pure VO2(B) sample (95.5 mAh/g). Therefore, Ni doping is an effective strategy for enhancing the lithium storage performance of VO2(B)

Room-temperature structure, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3(0 ≤ x ≤ 0.2)

In this study, the impacts of Nd doping on the structural, morphological, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3 (0 ≤ x ≤ 0.2) (LNSMO) have been investigated. LNSMO has been synthesized using the sol-gel technique (SG). XRD analysis revealed that LNSMO has a rhombohedral structure and belongs to the R-3c space group (No. 167). In addition, the XRD refinement using Fullprof software demonstrated that the cell volume and lattice parameters gradually reduced as Nd doping increased, confirming the gradual replacement of the La sites by Nd. The fitting of the Mn 2p peak by X-ray photoelectron spectroscopy (XPS) confirmed that Mn is in mixed valence (Mn3+, Mn4+), which contributes to the double exchange interactions (DE). It is confirmed by M−H that the paramagnetic (PM) - ferromagnetic (FM) transition of LNSMO is a second-order magnetic phase transition. There is a significant change in the magnetocaloric effect (MCE) around room temperature. The results of the magnetization measurements indicate that a reduction in the Curie temperature (Tc) and an increase in the Nd doping cause an increase followed by a decrease in the maximum magnetic entropy change (-ΔSMmax). On the contrary, the relative cooling power (RCP) first decreases and then increases. Therefore, we propose La0.62Nd0.18Sr0.2MnO3 sample with Tc = 300 K, -ΔSMmax = 4.22 J/(kg·K) and RCP = 253.39 (J/kg) under an external magnetic field. This material is potentially one of the candidates that could be used to develop magnetic refrigeration technology

Preparation of graphite phase carbon nitride (g-C3N4) micro-nano bouquet by thermal polymerization

A novel kind of g-C _3 N _4 micro-nano bouquets were successfully prepared via a simple method using melamine and ammonium chloride as raw materials. X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), x-ray energy spectrometer (EDX), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM),fourier transform infrared spectrometer (FT-IR) and x-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized samples. The results indicated that the samples presented graphitic C _3 N _4 micro-nano bouquets. Every microstructure was composed of many petals cross gathered along with the different directions. And the tip of every single petal contained quantities of nano bouquet structures with smaller diameters. In addition, abundant nanoparticles/nanorods distributed and intertwined together on the surface of the nano bouquet structure, and then formed cocoon-like porous morphology. Besides, based on the experimental results, the reasonable chemical reactions and the corresponding growth mechanism during the preparation process of g-C _3 N _4 micro-nano bouquets were proposed. Finally, the UV–vis results showed that the sample was a wide band gap (about 3.11 eV) semiconductor

In situ controlled rapid growth of novel high activity TiB2/(TiB2–TiN) hierarchical/heterostructured nanocomposites

In this work, a reaction coupling self-propagating high-temperature synthesis (RC-SHS) method was developed for the in situ controlled synthesis of novel, high activity TiB2/(TiB2–TiN) hierarchical/heterostructured nanocomposites using TiO2, Mg, B2O3, KBH4 and NH4NO3 as raw materials. The as-synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray energy dispersive spectroscopy (EDX), transition electron microscopy (TEM), high-resolution TEM (HRTEM) and selected-area electron diffraction (SAED). The obtained TiB2/TiN hierarchical/heterostructured nanocomposites demonstrated an average particle size of 100–500 nm, and every particle surface was covered by many multibranched, tapered nanorods with diameters in the range of 10–40 nm and lengths of 50–200 nm. In addition, the tapered nanorod presents a rough surface with abundant exposed atoms. The internal and external components of the nanorods were TiB2 and TiN, respectively. Additionally, a thermogravimetric and differential scanning calorimetry analyzer (TG-DSC) comparison analysis indicated that the as-synthesized samples presented better chemical activity than that of commercial TiB2 powders. Finally, the possible chemical reactions as well as the proposed growth mechanism of the TiB2/(TiB2–TiN) hierarchical/heterostructured nanocomposites were further discussed