Synthesis Of Ternary Compounds Research Articles

Surfactant-assisted synthesis of highly dispersed ZnS(C) /BiOBr/GO ternary composites for effectively improve the degradation ability of organic pollutants under visible light

In this paper, the highly dispersed ZnS(C)/BiOBr/ GO ternary composite was prepared by a two-step hydrothermal method with the help of the surfactant cetyltrimethyl ammonium bromide (CTAB). Its structure and morphology were studied by XRD, SEM, TEM, EDX spectra, UV–VIS absorption spectra, Mott-Schottky curve and Brunau-Emmett-Teller (BET) characterization. The results show that the ZnS(C)/BiOBr/GO ternary photocatalyst with excellent degradation effect and stable specific surface area has been successfully prepared. Orthogonal and photocatalytic experiments showed that the prepared photocatalyst had high photocatalytic performance for the degradation of brilliant blue (BB), Rhodamine B (RhB) and tetracycline hydrochloride (TCH). The degradation rate constants for BB, TCH and RhB were 0.12515, 0.06194 and 0.76750 min−1, respectively. Moreover, the photocatalytic performance of ZnS(C)/BiOBr/GO composite is significantly better than that of the original ZnS(C) and BiOBr. It is worth noting that ZnS(C)/BiOBr/GO ternary composite assisted by CTAB has the best photocatalytic activity, mainly for two reasons. First, the presence of surfactant CTAB significantly reduces the agglomeration of ZnS and enhances the dispersion of ZnS. Second, GO can be used as an electron trapping agent between ZnS and BiOBr to promote carrier separation. Therefore, the synthesis of ternary compounds with appropriate additional surfactants can effectively improve the photocatalytic efficiency of the degradation of organic pollutants. This study is expected to expand the application of surfactants in the preparation of semiconductor photocatalysts.

Synthesis of ternary compound in H–S–Se system at high pressures* *Project supported by the National Natural Science Foundation of China (Grant Nos. 51672279, 51727806, 11874361, and 11774354), the Science Challenge Project, China (Grant No. TZ2016001), the CAS Innovation Fund (Grant No. CXJJ-19-B08), and the CASHIPS Director’s Fund (Grant No. YZJJ201705).

The chemical reaction products of elemental sulfur (S), selenium (Se), and molecular hydrogen (H2) at high pressures and room temperature are probed by Raman spectroscopy. Two known compounds H2S and H2Se can be synthesized after laser heating at pressures lower than 1 GPa. Under further compression at room temperature, an H2S–H2Se and an H2S–H2Se–H2 van der Waals compounds are synthesized at 4 GPa and 6 GPa, respectively. The later is of guest–host structure and can be identified as (H2S) x (H2Se)(2−x)H2. It can be maintained up to 37 GPa at least, and the stability of its H2Se molecules is extended: the H–Se stretching mode can be detected at least to 36 GPa but disappears at 22 GPa in (H2Se)2H2. The pressure dependence of S–H and Se–H stretching modes of this ternary compound is in line with that of (H2S)2H2 and (H2Se)2H2, respectively. However, its hydrogen subsystem only shows the relevance to (H2S)2H2, indicating that this ternary compound can be viewed as H2Se-replaced partial H2S of (H2S)2H2.

BaTiO3 Thin Films from Atomic Layer Deposition: A Superlattice Approach

A superlattice approach for the atomic layer deposition of polycrystalline BaTiO3 thin films is presented as an example for an effective route to produce high-quality complex oxide films with excellent thickness and compositional control. This method effectively mitigates any undesirable reactions between the different precursors and allows an individual optimization of the reaction conditions for the Ba–O and the Ti–O subcycles. By growth of nanometer thick alternating Ba(OH)2 and TiO2 layers, the advantages of binary oxide atomic layer deposition are transferred into the synthesis of ternary compounds, permitting extremely high control of the cation ratio and superior uniformity. Whereas the Ba(OH)2 layers are partially crystalline after the deposition, the TiO2 layers remain mostly amorphous. The layers react to polycrystalline, polymorph BaTiO3 above 500 °C, releasing H2O. This solid-state reaction is accompanied by an abrupt decrease in film thickness. Transmission electron microscopy and Raman spect...

A phenomenological theory of ion-beam synthesis of ternary compound in silicon

A model for the annealing stage of ion-beam synthesis of a buried layer of a ternary phase in silicon coimplanted with a relatively low dose of chemically active ions is presented. Physically, the system under investigation is a mixture of precipitates of two binary phases which are formed in the subsurface region of silicon as a result of chemical reaction between each implanted impurity and matrix atoms. During annealing, the precipitates of each binary phase function as alternative sinks for the solutes. Therefore, the ensemble of new phase inclusions is regarded as a superposition of precipitate pairs. Each pair involves the nuclei of both binary phases. The incorporation of an impurity atom into a binary phase inclusion is assumed to be controlled by the corresponding kinetic parameter. During annealing, binary phase inclusions play the role of seeds for ternary phase formation. Mathematically, the redistribution and chemical segregation of implanted species are described by a set of diffusion equations. The sink terms of the equations have been derived in the two-particle approximation which reflects the competitive growth of two phases. Generally, this set of equations is solved numerically; however, two assumptions allow the analytic solution: there are (i) chemical segregation of the reagent is a predominant mechanism of phase formation; (ii) the phases formed have a constant chemical composition. The model is successfully applied to the description of silicon oxynitride synthesis by silicon implantation with a substoichiometric dose of oxygen and nitrogen ions. The computer simulation showed that nitrogen atoms, collected on the oxide surface, change the interface mechanism of oxide growth into that of bulk diffusion, which eventually facilitates the ternary phase formation.

Using Ultrathin-Film, Modulated Composites to Control the Reaction Mechanism of Ternary Compound Formation

ABSTRACTA predictable, controllable approach to the synthesis of ternary compounds through known intermediates is presented. Thin and ultrathin film superlattices were made in the Mo-Se, Cu-Se and Mo-Cu systems. Differential scanning calorimetry, low- and high-angle x-ray diffraction were used to assess the interdiffusion and nucleation reactions between elemental layers in these one-dimensional crystals. The experimental parameter modulation distance was used to influence the interfacial reactions. The results from each binary system were then used to predict the reaction pathway in the synthesis of a ternary compound, Cu2Mo6Se8. Superlattices with two different lengthscales were investigated. In the first, only one intermediate, MoSe2 which typically crystallizes at ∼200'C, is observed prior to the crystallization of Cu2Mo6Se8. In the second, no crystalline intermediates are observed below 6000 C.