Effect Of In2O3 Research Articles

Effect of In2O3 on the structural properties and catalytic performance of the CuO/ZnO/Al2O3 catalyst in CO2 and CO hydrogenation to methanol

Ternary CuO/ZnO/Al2O3 catalyst was synthesized through coprecipitation method and the effect of indium addition on the textural and catalytic performance was evaluated. The catalysts were tested at 50 atm and 250 °C in H2/CO/CO2, H2/CO and H2/CO2 feed. The presence of In2O3 resulted in structural promotions including enhanced BET and copper surface area, smaller copper crystals and increased oxygen vacancies. On the contrary, unexpected results were observed in catalytic activities in H2/CO/CO2 and H2/CO2 feeds. Pure In2O3 revealed the ability of direct hydrogenation of CO2 to methanol. In addition, it was observed that the addition of palladium into the catalyst remarkably enhanced the CO2 hydrogenation to methanol.

Domain evolution and corresponding piezoelectricity of lead-free In2O3-doped K0.5Na0.5NbO3 ceramics together with improved fatigue resistance and temperature stability

In this paper, (1-x)K0.5Na0.5NbO3-x mol% In2O3 (abbreviated as KNN-xIn) lead-free piezoelectric ceramics were prepared using conventional solid sintering method. The effects of In2O3 on the phase structure, microstructure, domain evolution, electrical properties, fatigue behavior and thermal stability of KNN ceramic matrix were systematically studied. XRD results show that all the ceramics possess the orthorhombic phase with domain architectures presented in the PFM. The addition of In2O3 improved the fatigue resistance owing to the enhanced density. The temperature stability of the 1.0 mol% In2O3 doped sample was significantly improved. It was found that the KNN ceramics with 1.0 mol% In2O3 addition exhibited good electrical properties (d33* = 179 pm/V, d33 = 103 pC/N, TC = 388 °C, Pr = 31.52 μC/cm2, εr = 327, tanδ = 3.28%). The results suggested that this material should be an attractive lead-free material for piezoelectric applications.

Effect of In2O3 on the grain connectivity and superconducting behavior of Bi2Sr2−xInxCaCu2O8+d

The effect of In2O3 on grain connectivity and superconducting properties of Bi-2212 was investigated. Indium was intentionally doped on the Sr-site of BSCCO at doping levels from x = 0 to x = 0.8. Accessing the Sr lattice site in BSCCO provides useful control on the possible effect of indium on its superconducting behavior and microstructural properties. Results show that the superconductivity persists in BSCCO even at high indium concentration (x = 0.8). However, secondary phases form at x ≥ 0.4 indium concentration affecting normal resistivity, magnetic susceptibility response and superconducting transition temperature of BSCCO. Formation of secondary phases weakens the diamagnetic intergrain coupling. An apparent increase in the formation of micron-sized grains is related to the increased sinterability of BSCCO with indium doping. The enhanced sinterability of BSCCO with indium provides possibility of synthesizing thin films with reduced thermal heat treatment.

Crystallization characteristics and properties of lithium germanosilicate glass-ceramics doped with some rare earth oxides

Lithium disilicate glass-ceramic, modified by GeO2/SiO2 replacement to give 33.60Li2O-5.00GeO2-61.40SiO2 (mol%) composition, was investigated by the conventional melt technique. The effect of adding 0.1mol of some rare earth oxides like Y2O3, La2O3 or CeO2 on the crystallization behavior, chemical durability, Vicker's microhardness, and density of the obtained glass-ceramics were studied. The effect of In2O3 was also investigated. The glass transition temperature (Tg) was reduced slightly by the replacement of GeO2/SiO2, while it markedly increased when GeO2-containing glass was doped with different rare earth or In2O3 oxides. Different forms of disilicate phases like Li2Si2O5, Y2Si2O7 and La2Si2O7 in addition to two forms of Li2(Ge,Si)2O5 and Li2(Ge,Si)O3 solid solution were developed. LiInSi2O6 of pyroxene structure, Li6Ge8O19 and CeO2 phases were also detected. The density values of the glass-ceramics vary from 2.38 to 3.14g/cm3 and the hardness was in the range of 4150–5585MPa. The chemical durability of the modified glass-ceramics was greatly improved. The modification of glass-ceramics with GeO2 or other dopant oxides led to producing of materials with more dense and ultra-fine microstructures. Such materials are promising for superior applications as catalysis, electrolyte in fuel cells, biomedical, as well as dental restorative applications.

Influence of In<sub>2</sub>O<sub>3</sub> Addition On The Magnetic And Electrical Properties of Iron – Deficient Ni-Zn Ferrite

The influence of low melting In2O3 addition on the magnetic and electrical properties of irondeficient ferrites of composition. Ni0.65Zn0.35Fe1.96O4 + xIn2O3(x = 0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03 and 0.035) was investigated. Single phase spinel structure of all sintered samples were confirmed by X-ray diffraction. The lattice parameter of the samples increased with the increment of In2O3. The effect of In2O3 (melting point 680°C) can be explained by the formation of liquid phase on the grain surface due to reaction of In2O3 with the spinel phase at 1250°C sintering temperature. Saturation magnetization decreased almost linearly and Curie temperature linearly with the increasing addition of In2O3. The decrease in magnetization was possibly due to diamagnetic In3+ ions occupy B-sublattice ( octahedral sites) and replace Fe3+ ions keeping the magnetization of A-sublattice (tetrahedral sites) unchanged. When indium ions occupy B-sites and replace Fe3+ ions, the magnetization of B-sublattice (MB) decreases keeping the magnetization of A-sublattice (MA) constant which in turn weakens A-B exchange interaction (M = MB-MA). The dc resistivity of the samples increased almost linearly with the addition of In2O3. With the increasing addition of In2O3, In3+ ions occupy B-sites which reduces Fe2+ to Fe3+ electron hoping conduction in octahedral sites and contributes to increase in resistivity. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12957 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 153-158, 2012

Nanoscale continuous In2O3 coating on phosphor particles for improved low-voltage cathodoluminescent properties

A nanoscale continuous coating of In2O3 on phosphors for low-voltage display applications is proposed in which the electrical conductivity of phosphor screen plays a major role. The effect of In2O3 coating by the sol-gel method on the cathodoluminescence (CL) of ZnGa2O4:Mn phosphors improves the intensity of low-voltage CL noticeably compared with that of In2O3 mixing. It is understood that electrically conductive channels are formed by a much smaller amount of In2O3 addition than that of In2O3 mixing. Especially, based on transmission electron microscopy analysis, the formation of uniform nanoscale continuous In2O3 layers on the phosphor surface was confirmed. Also, the structural and CL characterizations presented in this paper clearly demonstrate that the nanoscale encapsulation of In2O3 layers on phosphors served as protective layers retarding the CL degradation introduced by the low-energy electron irradiation, which is critically important for the development of low-voltage display applications.

Effects of In2O3 on the properties of (Co, Nb)-doped SnO2 varistors

The effects of In2O3 on the properties of (Co, Nb)-doped SnO2 varistors were investigated. It was found by characterizing the samples sintered at 1350°C that the nonlinear coefficient presents a peak of α = 20.4 for the concentration of 0.05 mol% In2O3, the average grain size decreases from 8.4 to 3.9 μm, the breakdown electrical field increases from 206 to 821 V mm−1 and relative electrical permittivity decreases from 2.3 to 0.16 k with increasing In2O3 from 0.00 to 0.10 mol%. The increase of the breakdown electrical field with increasing In2O3 concentration is mainly attributed to the decrease of the grain size. The reason why the permittivity decreases with increasing In2O3 concentration was originated from the ratio of the grain size to the barrier width. To illustrate the grain-boundary barrier formation of (In, Co, Nb) doped SnO2 varistors, a modified defect barrier model was introduced, in which the negatively charged acceptors substituting for Sn ions should not be located at the grain interfaces instead at SnO2 lattice sites of depletion layers.