Nguyen Huu Huy Phuc

Synthesis and characterization of graphite nanoplatelets

We report a facile method for the synthesis of graphite nanoplatelets (GNPs) from a carbon rod. GNPs were produced by vacuum filtration of a suspension obtained from electrochemically exfoliated carbon rods. The resulting GNPs were characterized using scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, and Raman spectroscopy. GNPs had sizes of 40–170 nm, thickness of 2.8–5.8 nm and were well dispersed in dimethyl sulfoxide. We discuss a possible mechanism for the formation of GNPs in our experiments.

Selective preparation of β-MoO3 and silicomolybdic acid(SMA) on MCM-41 from molybdic acid precursor and their partial oxidation performances

Abstract SMA(Mo/MCM-41Imp) and β-MoO 3 (Mo/MCM-41 Evap) were successfully prepared on MCM-41 using the molybdic acid solution. The molybdic acid solution is the effective precursor to generate selectively either SMA or β-MoO 3, and those species are anchored on MCM-41 through the formation of SMA. The Mo/MCM-41Imp catalyst showed a good catalytic performance for partial oxidation of methane to formaldehyde while the Mo/MCM-41 Evap is a promising catalyst for partial oxidation of methanol to formaldehyde.

Fast synthesis of Li2S–P2S5–LiI solid electrolyte precursors

A one-pot synthesis of Li2S–P2S5–LiI solid electrolyte precursors in a short time of 30 min is demonstrated by using ethyl propionate as a solvent. Li2S, P2S5 and LiI powders were shaken for different times in the solvent. The precursor suspension was evacuated at room temperature (RT) and then heated to 170 °C for 2 h to obtain Li7−0.08xP2S8−0.04xI solid electrolytes. A high ionic conductivity up to 4.6 × 10−4 S cm−1 at RT was achieved with x = 1 and a shaking time of 45 min. The formation of electrolyte precursors in 30 min is the shortest time that has ever been reported.

Selective Preparation of β- and α-Silicomolybdic Acid and Their Methanol Oxidative Behaviors

Abstractβ-silicomolybdic acid (SMA)/SiO2 was successfully prepared and its catalytic activity in methanol partial oxidation was studied. After catalytic study, β-SMA was transformed into two other types of α-MoO3 that had different Raman relative peaks ratios upon the pre-treatment prior to the reaction. On the other hand, α-SMA/SiO2 was also prepared for comparison. α-SMA was decomposed into surface oxomolybdates species which favored the formation of COx while MoO3 was formed from β-SMA and promoted HCHO formation.Graphical Abstract.

Raman study of the formation of beta silicomolybdic acid supported on silica, prepared by impregnation method

Beta silicomolibdic acid/silica (β-SMA, a metastable form of silicomolybdic acid - H(4)SiMo(12)O(40)) forms by the impregnation of fumed silica into molybdenum solution obtained by hydrolyzation of MoO(2)Cl(2.) β-SMA/silica is found to be stable up to 300 °C after calcination for 1h due to the existence of an interlayer MoO(3) between silica surface and β-SMA. Structures of molybdenum species in the preparation process (including precursor solution) were analyzed by Raman spectroscopy and XRD.

Cosmic ray research in Hanoi: The Auger experiment and measurements made at home

Abstract The VATLY is a new laboratory in Hanoi dedicated to research in the field of comic ray physics. Its various activities are briefly reviewed. The vertical cosmic muon flux has been measured using a segmented scintillator hodoscope and the results have been published in Ref. [1]. An orientable scintillation telescope has been constructed for measurement of the zenith angle dependence of the muon flux, of which preliminary results are reported here. They are in good agreement with the predictions of air shower model.