scholarly journals The Formation of Perovskite during the Combustion of an Energy-Rich Glycine–Nitrate Precursor

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5091
Author(s):  
Oksana Komova ◽  
Svetlana Mukha ◽  
Anna Ozerova ◽  
Galina Odegova ◽  
Valentina Simagina ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
High Temperatures ◽  
Reaction Zone ◽  
Perovskite Phase ◽  
Solution Combustion Synthesis ◽  
Attenuated Total Reflection ◽  
Solution Combustion ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Nitrate Precursor

The effect of different regimes of combustion of glycine–nitrate precursors on the formation of perovskite phases (LaMnO3 and LaCrO3) without additional heat treatment was studied. The following three combustion regimes were compared: the traditional solution combustion synthesis (SCS), volume combustion synthesis (VCS) using a powdered precursor, and self-propagating high-temperature synthesis (SHS) using a precursor pellet. The products of combustion were studied using a series of physicochemical methods (attenuated total reflection infrared spectroscopy (ATR FTIR), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and thermal analysis). SHS was found to be the most productive regime for the formation of perovskite because of its ability to develop high temperatures in the reaction zone, which led to a reduced content of the thermally stable lanthanum carbonate impurities and to an increased yield and crystallite size of the perovskite phase. The reasons for the better crystallinity and purity of LaCrO3 as compared with LaMnO3 is also discussed, namely the low temperatures of the onset of the thermolysis, the fast rate of combustion, and the favorable thermodynamics for the achievement of high temperatures in the reaction zone.

scholarly journals ONE-STEP SYNTHESIS OF POLYMETALLIC NANOPARTICLES IN AIR INVIRONMENT

2018 ◽  
Vol 61 (9-10) ◽  
pp. 42-47 ◽  
Author(s):  
Valentin I. Romanovsky ◽  
Alexander A. Hort ◽  
Kirill B. Podbolotov ◽  
Nikolay Yu. Sdobnyakov ◽  
Vladimir S. Myasnichenko ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Oxide ◽  
Combustion Synthesis ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron ◽  
One Step

In this work, we studied possibility to obtain bimetallic nanopowders by our modified solution combustion synthesis method using citric acid as a fuel. Stoichiometric amounts of metal nitrates with metal to metal ratios 1:1 and 1:2 and fuels with final oxidizer to fuel ratio of 1.75 were used as initial components to prepare aqueous solutions. The almost complete absence of metal oxide phases was confirmed by energy-dispersive X-ray spectroscopy. The X-ray diffraction analysis of obtained materials showed that all samples are pure bimetallic nanopowders with distorted cubic crystal structure of each metal. According to high resolution transmission electron microscopy the mean diameter of metallic particles are about 10 nm for all nanopowders. The calculated interplanar distances of crystals of metal particles as well as detailed scanning transmission electron microscopy studying showed uniform distribution of different metal spices into nanoparticles. Thus, we can conclude the nanopowders are bimetallic particles with co-integrated crystal structures of different metalic spices. We suppose, the possibility of solution combustion synthesis of bimetallic nanopowder in the air environment is due to a combination of type and amount of the fuels as well as technological conditions of the synthesis. These lead to rapid combustion process at low temperature. In addition, protective inert atmosphere appears above freshly synthesized metal nanopowders during thermal decompositions of the fuels that eventually prevent metal oxidation. Modified SCS method could be successfully used for one-step synthesis of complex oxide-oxide and metal-oxide core-shell nanostructures. For citation: Romanovskii V.I., Khort A.A., Podbolotov K.B., Sdobnyakov N.Y., Myasnichenko V.S., Sokolov D.N. One-step synthesis of polymetallic nanoparticles in air invironment. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 42-47

scholarly journals Fabrication of La2O3 Uniformly Doped Mo Nanopowders by Solution Combustion Synthesis Followed by Reduction under Hydrogen

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2385 ◽  
Author(s):  
Siyong Gu ◽  
Mingli Qin ◽  
Houan Zhang ◽  
Jidong Ma
Keyword(s):  
Combustion Synthesis ◽  
Hydrogen Reduction ◽  
Synthesis Method ◽  
Reduction Process ◽  
Solution Combustion Synthesis ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron

This work reports the preparation of La2O3 uniformly doped Mo nanopowders with the particle sizes of 40–70 nm by solution combustion synthesis and subsequent hydrogen reduction (SCSHR). To reach this aim, the foam-like MoO2 precursors (20–40 nm in size) with different amounts of La2O3 were first synthesized by a solution combustion synthesis method. Next, these precursors were used to prepare La2O3 doped Mo nanopowders through hydrogen reduction. Thus, the content of La2O3 used for doping can be accurately controlled via the SCSHR route to obtain the desired loading degree. The successful doping of La2O3 into Mo nanopowders with uniform distribution were proved by X-ray photon spectroscopy and transmission electron microscopy. The preservation of the original morphology and size of the MoO2 precursor by the La2O3 doped Mo nanopowders was attributed to the pseudomorphic transport mechanism occurring at 600 °C. As shown by X-ray diffraction, the formation of Mo2C impurity, which usually occurs in the direct H2 reduction process, can be avoided by using the Ar calcination-H2 reduction process, when residual carbon is removed by the carbothermal reaction during Ar calcination at 500 °C.

Solution-Combustion Synthesis and Study of : γ-Fe2-xCrxO3(0.75 ≤ x ≤ 1.25) Maghemite-like Materials

2008 ◽  
Author(s):  
Emilio Moran ◽  
Miguel ïngel. Alario-Franco ◽  
Marco L. Garcia-Guaderrama ◽  
Oscar Blanco
Keyword(s):  
Combustion Synthesis ◽  
Solution Combustion Synthesis ◽  
Solution Combustion

Effect of Nitric Acid Modification on LiMn2O4 Prepared by Solution Combustion Synthesis

2011 ◽  
Vol 80-81 ◽  
pp. 332-336 ◽  
Author(s):  
Yan Xia ◽  
Mei Huang ◽  
Jun Ming Guo ◽  
Ying Jie Zhang
Keyword(s):  
Nitric Acid ◽  
Combustion Synthesis ◽  
Discharge Capacity ◽  
Retention Rate ◽  
Solution Combustion Synthesis ◽  
Manganese Acetate ◽  
Solution Combustion ◽  
Acid Modification ◽  
Capacity Retention ◽  
Liquid Combustion

Effect of nitric acid and the burning time on the liquid combustion synthesis of spinel LiMn2O4 has been studied, using lithium nitrite and Manganese acetate as raw a material. The results show that the main phases are all LiMn2O4, which can be obtained at 400-600 oC. Before modified, the impurity is Mn3O4 or Mn2O3. After modified, the impurity is only Mn3O4. The aggregation obviously reduced after adding nitric acid, it is indicated that the crystalline increased. With the increasing temperatures, the modified particle size was increased and the aggregation reduced. The initial discharge capacity and cycle stability improved at some extent too. Its first discharge capacity was 104.6, 112.8 and 117.7mAh/g synthesized at 400, 500, 600 oC, respectively, and the 30th capacity retention rate were 84.89%, 80.67% and 73.24%.

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