Volume Ratio Of Glycerol Research Articles

Effect of the glycerol dispersant on the structure, electrical transport and magnetoresistive properties of La0.67Ca0.33MnO3 ceramics prepared by the sol-gel routine

In this paper, the sol-gel technique is employed to synthesize polycrystalline La0.67Ca0.33MnO3 (LCMO) ceramics, where methanol is chosen as the solvent. The crystal structure, morphology, as well as electrical and magnetoresistive properties were examined. Moreover, the effect of amount of the dispersant glycerol on the properties of LCMO ceramics is studied. X-ray diffraction (XRD) results showed that all samples crystallized in single phases with orthogonal perovskite structure (pnma space group), without any detectable impurity phases. Results reveal that the grain size of LCMO ceramics exhibits an initial increase followed by a decrease, accompanied by a similar behavior in the temperature coefficient of resistance (TCR) and magnetoresistance (MR). When the volume ratio of glycerol and methanol reached 2 %, the grain size is determined to be 7.30 μm, with TCR value of 25.02 % K−1 at T= 263.2 K, and MR value recorded at 55.40 %. The study elucidates the influence of glycerol on LCMO polycrystalline ceramics and optimize the fabrication process, thereby improve the electric transport property and magnetoresistance.

Alcohol-Induced Synthesis of Photocatalytic TiO2 with Controlled Hierarchical Structure

Three-dimensional (3D) hierarchical TiO2 structures were obtained by a facile solvothermal process. Various analytical techniques were used to characterize the crystal phase, morphology and optical absorption of the obtained samples. The experimental results indicate that the morphology could be tailored by adjusting the volume ratio of glycerol to ethanol. The investigation of photocatalytic performance shows that all the as-prepared TiO2 samples possess an excellent photocatalytic activity superior to commercial P25 in the degradation of Rhodamine B (RhB) dye under UV-light irradiation. In addition, the optimized volume ratio of ethanol to glycerol is 20 : 15. The possible mechanism related to the photocatalytic activity of the sample is discussed in detail. The enhanced photocatalytic activities of TiO2 samples could result from their hierarchical structures assembled by 1D nanorods and large light-harvesting efficiency.

A mild alcohol-salt route to synthesize α-hemihydrate gypsum microrods from flue gas desulfurization gypsum in large scale

In this work, α-hemihydrate gypsum (α-HH) microrods were synthesized in large scale using flue gas desulfurization (FGD) gypsum as the raw materials in alcohol-salt system under normal pressure. The preparation conditions were investigated and optimized as follows: the concentration of Ca2+ was 2.9 mol·L−1, the concentration of Mg2+ was 0.0315 mol·L−1, the volume ratio of glycerol was 6%, the reaction time was 4 h, reaction temperature 92 °C, and the concentration of glucose 0.0370 mol·L−1. The α-HH sample prepared under the as-optimized conditions was characterized by means of x-ray diffraction (XRD), energy dispersive spectrometer (EDS), differential scanning calorimeter (TG-DSC), scanning electron microscopy (SEM), fourier transform infrared (FT-IR) and transmission electron microscope (TEM). The results show that the sample was well developed α-HH microrods and performed uniform morphology with length up to approximately 100 μm and aspect ratio of 35:1. The formation mechanism of α-HH microrods was consistent with the growth mechanism of screw dislocation.

Glycerol and Water Mediated Synthesis of Silver Nanowires in the Presence of Cobalt Chloride as Growth Promoting Additive

High quality silver nanowires (AgNWs) were synthesized by using CoCl2 as a growth promoting additive in glycerol/water combination as a solvent. This method is not only time saving but also helpful to control morphology of AgNWs. A series of experiments were performed to optimize volume ratio of glycerol to water (G/W). The synergetic effect of the volume ratio of G/W and concentration of growth promoting additive on the morphology of AgNWs was investigated. The possible mechanism for the growth of AgNWs was elucidated by monitoring in situ generation of AgCl as a prominent event. Controlled experiments were performed to investigate the role of individual cobalt and chloride ions by using Co(NO3)2 and NaCl, respectively. The obtained AgNWs were characterized by SEM, TEM and XRD, while surface properties of the obtained AgNWs were studied by XPS. It was found that at specific volume ratio of G/W (3.5:1), mole ratio of PVP to AgNO3 (0.7:1) and concentration of CoCl2 (4 mM), high quality AgNWs were obtained.

Preparation of Titanium Dioxide Nanotube Arrays and Photocatalytic Degradation of Methyl Orange

This paper adopted electrochemistry anodic oxidation method for preparing TiO2nanotube array membrane on a pure titanium sheet. The results showed that TiO2nanotube arrays were regularly obtained when anodizing voltage at 25V, anodizing time in 60min , NH4F concentration at 0.25mol·L-1, and volume ratio of glycerol and water at 2:1. Using of this titanium dioxide nanotube array photocatalyst, and Under light of ultraviolet lamp, the photocatalytic degradation of methyl orange solution was studied in this paper. The main factors affecting the test selection was: the concentration of methyl orange solution (5mg·L-1, 10mg·L-1, 15mg·L-1, 25mg·L-1, 35mg·L-1), pH of methyl orange solution (2.0,2.5,3.0,3.5, 4.0,5.0,5.5,6.0), catalytic time (30min.60min, 90min, 120min, 150min, 180min, 240min), UV light source (6w, 11w, 15w).