12017-13-9Relevant academic research and scientific papers
A general solvothermal route to the synthesis of CoTe, Ag2Te/Ag, and CdTe nanostructures with varied morphologies
Jiang, Ling,Zhu, Ying-Jie
, p. 1238 - 1243 (2010)
A general and facile surfactant-assisted solvothermal route was developed, for the synthesis of CoTe, Ag2Te/Ag, and CdTe nanostructures using the corresponding metal salt, Na2TeO3, ascorbic acid, and polyvinyl pyrrolidone (PVP) or cetyltrimethylammonium bromide (CTAB) in mixed solvents of ethanolamine and water. It was also found that the morphology of the product varied dramatically when using different surfactants such as PVP and CTAB. A formation mechanism, of telluride nanostructures was proposed. The products were characterized, by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry (TG), and differential scanning calorimetric (DSC) analysis.
Optical and electrical studies of vapour phase grown Cd1-xCoxTe crystals
Reddy, Y. Dwarakanadha,Reddy,Reddy, D. Sreekantha,Reddy
, p. 934 - 938 (2008)
The optical properties of vapour phase grown crystals of diluted magnetic semiconductor (DMS) Cd1-xCoxTe were investigated for x = 0.001, 0.003, 0.005, 0.007 and 0.009. The reflectivity spectra exhibited a regular shift in the fundamental absorption edge (E0) with composition x. The reflectivity spectra for the present samples of Cd1-xCoxTe of all compositions exhibit broad bands at 5300 and 11,100 cm-1 due to the transitions of 4A2 → 4T1 (F) and 4A2 → 4T1 (P), respectively. Temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited p-type conductivity.
Improved performance of a CoTe//AC asymmetric supercapacitor using a redox additive aqueous electrolyte
Ye, Beirong,Gong, Chao,Huang, Miaoliang,Tu, Yongguang,Zheng, Xuanqing,Fan, Leqing,Lin, Jianming,Wu, Jihuai
, p. 7997 - 8006 (2018)
Cobalt telluride (CoTe) nanosheets as supercapacitor electrode materials are grown on carbon fiber paper (CFP) by a facile hydrothermal process. The CoTe electrode exhibits significant pseudo-capacitive properties with a highest Cm of 622.8 F g-1 at 1 A g-1 and remarkable cycle stability. A new asymmetric supercapacitor (ASC) is assembled based on CoTe (positive electrode) and activated carbon (negative electrode), which can expand the operating voltage to as high as 1.6 V, and has a specific capacitance of 67.3 F g-1 with an energy density of 23.5 W h kg-1 at 1 A g-1. The performance of the ASC can be improved by introducing redox additive K4Fe(CN)6 into alkaline electrolyte (KOH). The results indicate that the ASC with K4Fe(CN)6 exhibits an ultrahigh specific capacitance of 192.1 F g-1 and an energy density of 67.0 W h kg-1, which is nearly a threefold increase over the ASC with pristine electrolyte.
Magnetic-dipolar-interaction-induced self-assembly affords wires of hollow nanocrystals of cobalt selenide
Gao, Jinhao,Zhang, Bei,Zhang, Xixiang,Xu, Bing
, p. 1220 - 1223 (2006)
(Figure Presented) Giving cobalt some stick: A general strategy for the synthesis of 1D assemblies of hollow nanocrystals is presented. Cobalt nanostructures assembled through magnetic dipolar interactions (see scheme) are used as templates for the formation of wires of hollow nanocrystals of CoSe 2 (and Co3S4, CoTe). The wires of hollow CoSe2 nanocrystals are ferromagnetic, with a Curie temperature of 570 K.
Regularities of thermal decay of carbonyl chalcogenide metal clusters
Pasynskii,Dobrokhotova,Torubaev,Semenova,Novotortsev
, p. 109 - 115 (2003)
The thermal decay of 19 individual carbonyl homo- and heterochalcogenide clusters with different M/X ratios (M = Fe, Mn, Pt, Cr, W, Mo, Re, Ru; X = S, Se, Te) was studied by differential scanning calorimetry and thermogravimetry. The process is stepwise a
Hydrothermal synthesis of cobalt telluride nanorods for a high performance hybrid asymmetric supercapacitor
Dhanuskodi, S.,Manikandan, M.,Sathish, M.,Subramani, K.
, p. 13632 - 13641 (2020)
Cobalt telluride nanostructured materials have demonstrated various applications, particularly in energy generation and storage. A high temperature and reducing atmosphere are required for the preparation of cobalt telluride-based materials, which makes this a difficult and expensive process. The development of a facile route for producing the desirable nanostructure of cobalt telluride remains a great challenge. We demonstrated a simple hydrothermal method for preparing cobalt telluride nanorods (CoTe NRs) and telluride nanorods (Te NRs) for supercapacitor applications. The morphology of CoTe NRs and Te NRs was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The prepared CoTe NR electrode material exhibited a high specific capacity of 170 C g-1 at a current density of 0.5 A g-1 with an exceptional cyclic stability. The asymmetric supercapacitor was assembled using CoTe NRs and orange peel-derived activated carbon (OPAA-700) as a positive and negative electrode, respectively. The fabricated device delivered a high energy density of 40.7 W h kg-1 with a power density of 800 W kg-1 at 1 A g-1 current density. When the current density was increased to 30 A g-1, the fabricated device delivered a high power density of 22.5 kW kg-1 with an energy density of 16.3 W h kg-1. The fabricated asymmetric supercapacitor displayed a good cyclic stability performance for 10000 cycles at a high current density of 30 A g-1 and retained 85% of its initial capacity for after 10000 cycles. The prepared materials indicate their applicability for high performance energy storage devices.
Structure, density, and microhardness of Co1- xNixTe (0 < x < 1) solid solutions
Makovetskii,Vas'kov,Yanushkevich
, p. 108 - 110 (2002)
Co1-xNixTe (0 a continuous series of solid solutions was confirmed by density and microhardness measurements.
Phase-Selective Syntheses of Cobalt Telluride Nanofleeces for Efficient Oxygen Evolution Catalysts
Gao, Qiang,Huang, Chuan-Qi,Ju, Yi-Ming,Gao, Min-Rui,Liu, Jian-Wei,An, Duo,Cui, Chun-Hua,Zheng, Ya-Rong,Li, Wei-Xue,Yu, Shu-Hong
, (2017)
Cobalt-based nanomaterials have been intensively explored as promising noble-metal-free oxygen evolution reaction (OER) electrocatalysts. Herein, we report phase-selective syntheses of novel hierarchical CoTe2 and CoTe nanofleeces for efficient
Synthesis of uniform CoTe and NiTe semiconductor nanocluster wires through a novel coreduction method
Peng, Qing,Dong, Yajie,Li, Yadong
, p. 2174 - 2175 (2003)
A novel coreduction method was developed to synthesize uniform one-dimensional CoTe and NiTe nanocluster wires. In the synthesis, soluble Na2TeO3 was used to supply a highly reactive Te source and N2H4·H2O was used both as reducing agent and as complexing agent. The as-prepared samples were characterized by XRD, TEM, and HRTEM. The probable formation mechanism of the nanowires is discussed.
Preparation, crystal structures, experimental and theoretical electronic band structures of cobalt tellurides in the composition range CoTe1.3-CoTe2
Muhler,Bensch,Schur
, p. 2947 - 2962 (1998)
Cobalt tellurides in the composition range CoTe1.3-CoTe2 crystallize in a Cdl2-type structure with short intra- and interslab Te-Te contacts indicating a polymeric network with multiple Te-Te bonds explaining the very low c/a values of 1.38 to 1.41 of the hexagonal cells. Single-crystal x-ray investigations performed on CoTe2 confirm the marcasite-type structure in the centrosymmetric space group Pnnm. Experimental valence band spectra (UPS) confirm that the Co tellurides in the composition range CoTex (1.3 F decreases with the Te content and is due to Co 3d and Te 5p states. This assignment is supported by the results of the calculated density of states curve (DOS) which demonstrates that Te p states contribute about 50% in the Cdl2-type and about 35% in the marcasite-type structure. The Te d states contribute about 15% to the total Te contributions. This behaviour cannot be understood on the basis of a simple tight-binding description, ignoring d-valence states of Te. Core level spectra (XPS) suggest that all CoTex samples are best described as intermetallic compounds. Small chemical shifts between the different samples are mainly due to the different Madelung contributions rather than to changes of the electron density located on the Co atoms. An oxidation number for Te x samples is deduced, in good agreement with the value of about -1.3 for the Te in CoTe2 that would be deduced from the relation between the Te-Te distances versus oxidation states of the anion in (Te2)-11, Te-11. The three-dimensional character of the Co tellurides deduced from the crystal structure is further confirmed by the calculated energy dispersion E(k).
