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Том 27, № 3 (2018)
- Год: 2018
- Статей: 13
- URL: https://journals.rcsi.science/1061-3862/issue/view/12290
Article
Solution Combustion Synthesis of Complex Oxide Semiconductors
Аннотация
This is a perspective of the role that combustion synthesis, specifically solution combustion synthesis, has played in the development of ternary and quaternary metal oxide semiconductors, and materials derived from these compounds such as composites, solid solutions, and doped samples. The attributes of materials, collectively termed ‘complex oxides’ within the context of this discussion, are discussed in terms of their applicability in the generation of solar fuels from water splitting and CO2 reduction, and environmental pollution remediation via heterogeneous photocatalysis.
129-140
Preparation of Nanoparticles via Cellulose-Assisted Combustion Synthesis
Аннотация
Cellulose-assisted combustion synthesis is a simple and effective continuous synthesis method that emerged almost a decade ago and now witnessing exponential growth in research interest and application. The simplicity of the process and easily scalable nature makes it appropriate for industrial scale synthesis of nanomaterials with high surface area and large porosity. Over the past few years, catalysis community has devoted considerable efforts in exploiting these properties borne naturally in combustion-synthesized materials such as complex surface structure and large porous volume providing suitable surface sites for catalytic reactions. In this review article, we plan to gather this development in the cellulose-assisted combustion synthesis and gain some insights related to possible future outlook and research needs.
141-153
Solution-Combustion Synthesis of LiNi1/3Co1/3Mn1/3O2 as a Cathode Material for Lithium-Ion Batteries
Аннотация
A cathode material for lithium-ion batteries–LiNi1/3Co1/3Mn1/3O2–was prepared by solution combustion synthesis and characterized by XRD, SEM, and galvanostatic charge/discharge cycling. The sample calcined at 950°C for 10 h showed best charge/discharge performance. An initial discharge capacity (C) of 150.5 mA h g–1 retained 95.7% of its value after 75 charge/discharge cycles at Ic = 14 mA g–1 (0.2C rate), Id = 70 mA g–1 (0.5C rate).
154-161
Transformations of Iron (III) Precursors in a Wave of Flameless RDX Combustion
Аннотация
Flameless combustion of 40% Fe2O3 – 40% RDX – 20% HDI (mix I) and 30% CoCO3 – 15% iron formate – 40% RDX – 15% HDI (mix II) systems was explored by time-resolved X-ray diffraction (TRXRD). In case of mix I, the reaction was found to proceed via the formation of FeO intermediate: Fe2O3 → FeO → Fe3O4. Variation in the extent of iron reduction was associated with dynamic temperature change and a reductant content of the reaction zone. The reduction proceeded as a solid-state reaction, without amorphization of the structure. The process in system II involved the formation of CoO and FeO intermediates. Further reduction – up to metals – takes place behind the combustion front and yields a mixture of nanosized Co, Fe, and Co0.7Fe0.3 particles. Exposure of hot reaction products – nano-sized Co and Fe – to the air leads to their self-ignition and formation of Co3O4 and Fe3O4, respectively.
162-166
Magnetoelectric Composites yNi1−xCdxFe2O4 + (1 − y)Ba0.8Sr0.2TiO3 (x = 0.2, 0.4, 0.6; y = 0.15, 0.30, 0.45): Solution-Combustion Synthesis and Microwave Properties
Аннотация
Magnetoelectric composites yNi1−xCdxFe2O4 + (1 − y)Ba0.8Sr0.2TiO3 (x = 0.2, 0.4, 0.6; y = 0.15, 0.30, 0.45) were prepared by solution-combustion synthesis and characterized by XRD, SEM, and MW measurements. Low MW transmittance (about 0.15) was obtained at f = 8.5 GHz for composites with x = 0.6, y = 0.45. The MW reflectance did not show any dependence on Cd content x. The MW absorptivity levels-off at higher f. A maximum value of dielectric constant (about 42.6) is observed at f = 8.5 GHz for composites with x = 0.6, y = 0.45. Our composites seem promising for use in tunable microwave devices.
167-173
Structural, Electrical, and IR Properties of CuxCo1–xFe2O4 (x = 0, 0.4, 1.0) Prepared by Solid-State Method
Аннотация
The effect of copper doping on cobalt ferrites CuxCo1–xFe2O4 (x = 0, 0.4, 1.0) prepared by solid-state method was studied in detail. According to XRD results, the Co–Cu ferrites calcined at 800°C exhibited better crystallinity. Average crystallite sizes varied within the range 18–29 nm. The infrared spectra revealed two principal absorption bands, the high-frequency one ν1 around 600 cm−1 and the low-frequency one ν2 around 400 cm−1, attributed to stretching vibrations of the oxygen–metal bond in the tetrahedral (A) and octahedral (B) sites in the spinel lattice, respectively. The electrical properties of the material were semiconducting in their character. The results were used to obtain the following parameters: force constants for tetrahedral (Kt) and octahedral sites (Ko), Young’s modulus (E), rigidity modulus (G), bulk modulus (B), micro strain (ε), Debye temperature (ΘD), X-ray density (ρX), dislocation density (ρD), transverse (Vt) and longitudinal (Vl) wave velocities.
174-179
Crystallization of Amorphous Antimony at Room Temperature: Non-Uniqueness of Patterning Route
Аннотация
Room-temperature crystallization of ‘explosive’ amorphous antimony was found to exhibit the phenomenon of non-uniqueness: it may spontaneously proceed (in identical samples) either within 27 days or within 67 days to yield crystallites with different preferential orientation. Apparently, this happens due to structural fluctuations in the initial amorphous matter, whereas the formation of different textures is governed by the minimization of surface energy. The phenomenon may turn useful for regulating a structure of Sb compounds in advanced semiconducting materials.
180-183
Brief Communications
Composition and Structure of Ferrochromium SHS-Produced from (Mg,Fe)(Cr,Al)2O4 Ore Concentrate
184-185
Hard Facing of Exploclad Steel Bimetals by Metallothermic SHS
186-188
SHS of TiC–Ni Composites from Powdered and Granulated (Ti + C) + xNi Mixtures
189-191
SHS Joining of Ti–C–Si Ceramics with Tantalum
192-194
Solution-Combustion Synthesis and Characterization of Fe3O4 Nanoparticles
195-197
Combustion of Ti–B Mixtures in Argon Coflow: Impact of H2 + B Reaction
198-199