scholarly journals Properties of Molybdenum–Tungsten Blue Nanoparticles as a Precursor for Ultrafine Binary Carbides

2020 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Maria Myachina ◽  
Natalia Gavrilova ◽  
Ksenia Poluboyarinova ◽  
Victor Nazarov
Keyword(s):  
Ascorbic Acid ◽  
Light Scattering ◽  
Hydrochloric Acid ◽  
Carbon Source ◽  
Size Structure ◽  
Sol Gel ◽  
Electronic Microscopy ◽  
Molybdenum Blue ◽  
Carbide Particles ◽  
Tungsten Nanoparticles

A promising method for the synthesis of ultrafine carbide particles is the sol–gel method using dispersions of molybdenum–tungsten nanoparticles. For further use, the main properties of molybdenum-blue nanoparticles, including the size, structure, and stability, under different conditions must be determined. The synthesis of dispersions of molybdenum–tungsten blue was carried out as a result of the reduction of molybdate and tungstate ions in the presence of hydrochloric acid. Ascorbic acid was chosen as a reducing agent and further acted as a carbon source. Dispersions and nanoparticles were investigated by transmission electronic microscopy (TEM), UV/vis and infrared (FTIR) spectroscopy, and dynamic light scattering (DLS).

Li2MnSiO4/C Composite with Ascorbic Acid as Carbon Source for Lithium Ion Batteries

2014 ◽  
Vol 1033-1034 ◽  
pp. 125-128
Author(s):  
Chun Yan Lai ◽  
Zhen Wang ◽  
Jia Jun Zhu ◽  
Qun Jie Xu
Keyword(s):  
Ascorbic Acid ◽  
Carbon Source ◽  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Discharge Capacity ◽  
Sol Gel ◽  
Lithium Ion ◽  
Gel Method ◽  
Sol Gel Method

Ascorbic acid (VC) was used as carbon source for Li2MnSiO4/C composite synthesized by a sol-gel method. By comparing the electrochemical performance of the Li2MnSiO4/C composite and pure Li2MnSiO4, it was found that VC adding can improve the capacity of Li2MnSiO4. The Li2MnSiO4/C with 10% VC shows a discharge capacity of 212 mAh/g at 0.05C and Li2MnSiO4/C with 15% VC shows discharge capacity of 192 mAh/g at 0.1C, that were higher than the capacity of pure Li2MnSiO4.

scholarly journals Molybdenum–Tungsten Blue Nanoparticles as a Precursor for Ultrafine Binary Carbides

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 761
Author(s):  
Maria Myachina ◽  
Natalia Gavrilova ◽  
Ksenia Poluboyarinova ◽  
Victor Nazarov
Keyword(s):  
Particle Size ◽  
Electronic Microscopy ◽  
Medium Ph ◽  
X Ray ◽  
Molar Ratios ◽  
Long Term Stability ◽  
Carbide Particles ◽  
Tungsten Nanoparticles ◽  
Nanoparticles Dispersions

Herein, we demonstrate a promising method for the synthesis of ultrafine carbide particles using dispersions of molybdenum–tungsten nanoparticles. Dispersions of molybdenum–tungsten blue nanoparticles with different initial molar ratios of molybdenum/tungsten were synthesized through the reduction of molybdate and tungstate ions by ascorbic acid in an acidic medium (pH = 1.0–2.5). Molybdenum–tungsten blue nanoparticles were characterized by ultraviolet–visual (UV–VIS), infrared (FTIR), and X-ray photoelectron (XPS) spectroscopies; transmission electronic microscopy (TEM); and dynamic light scattering (DLS). We demonstrated that molybdenum–tungsten blue nanoparticles belong to toroidal polyoxometalate clusters (λmax = 680–750 nm) with a predominant particle size of 4.0 nm. Molybdenum–tungsten blue dispersions were shown to be monodispersed systems with a small particle size and long-term stability (>30 days) and are suitable for further catalytic applications.

Ethers as Oxygen Donor and Carbon Source in Non-hydrolytic Sol-Gel: One-Pot, Atom-Economic Synthesis of Mesoporous TiO2 -Carbon Nanocomposites

2018 ◽  
Vol 24 (19) ◽  
pp. 4982-4990 ◽  
Author(s):  
Angel Manuel Escamilla-Pérez ◽  
Nicolas Louvain ◽  
Bruno Boury ◽  
Nicolas Brun ◽  
P. Hubert Mutin
Keyword(s):  
Carbon Source ◽  
Sol Gel ◽  
Mesoporous Tio2 ◽  
One Pot ◽  
Carbon Nanocomposites ◽  
Oxygen Donor

Time-Resolved Small Angle X-Ray Scattering and Dynamic Light Scattering Studies of Sol-Gel Transition in Gelatin

1988 ◽  
Vol 143 ◽  
Author(s):  
Dan Q. Wu ◽  
Benjamin Chu
Keyword(s):  
Light Scattering ◽  
Cross Section ◽  
Sol Gel ◽  
Slow Mode ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Saxs Intensity ◽  
Sol Gel Transition ◽  
Gel Transition

AbstractStructural and dynamical properties of an aqueous gelatin solution (5 wt%, 0.1M NaCi, pH=7) in a sol-gel transition were studied by time-resolved small angle x-ray scattering (SAXS) and dynamic light scattering (DLS) after quenching the gelatin sol at ∼45”C to 11°C. SAXS intensity measurements suggested the presence of gel fibrils which grew initially in cross-section. The average cross-section of the gel fibrils reached a constant value after an initial growth period of ∼800 sec. Further increase in SAXS intensity could be attributed to the increase in the length of the gel fibrils. Photon correlation, on the other hand, clearly showed two relaxation modes in both the sol and the gel (∼1 hr after the quenching process) states: a fast cooperative diffusion mode which remained constant from the sol to the gel state after correction for the temperature dependence of solvent viscosity; and a slow mode that could be attributed to the self-diffusion of the “free” gelatin chains and aggregates. The slow mode contribution to the time correlation function was reduced from ∼40% in sol to ∼20% in gel signaling a decrease but not the elimination of “free” particles in the gel network. The decrease in the intensity contribution by the slow mode is, however, accompanied by a large increase in the characteristic line-width distribution.

Crystallization of nanosized titania particles prepared by the sol-gel process

1994 ◽  
Vol 9 (8) ◽  
pp. 2102-2108 ◽  
Author(s):  
E. Haro-Poniatowski ◽  
R. Rodríguez-Talavera ◽  
Heredia M. de la Cruz ◽  
O. Cano-Corona ◽  
R. Arroyo-Murillo
Keyword(s):  
Particle Size ◽  
Steady State ◽  
Light Scattering ◽  
Sol Gel ◽  
X Ray ◽  
Constant Size ◽  
Size Profile ◽  
Nanosized Titania ◽  
Sol Gel Process ◽  
Kinetics Of

Sols of titania were obtained by the sol-gel method and their size profile was followed by dynamical light scattering. In the early stages of the reaction an unstable behavior was detected. After this unstable regime the particle size reaches a steady state where the sols have a constant size while increasing in number. Once the sol concentration reaches its overlap value, the gelation regime takes place. For samples prepared in this way Raman spectra and x-ray diffractometry were used to characterize the kinetics of crystallization of the material.

Sign in / Sign up

Export Citation Format

Share Document