Fabrication of Layered Niobium Oxysulfide and Investigation of Structural and Elemental Composition
- PDF / 103,539 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 40 Downloads / 200 Views
0988-QQ03-15
Fabrication of Layered Niobium Oxysulfide and Investigation of Structural and Elemental Composition Kazuyoshi Izawa, Shintaro Ida, Ugur Unal, Tomoki Yamaguchi, and Yasumichi Matsumoto Department of Nano Science and Technology, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555, Japan
ABSTRACT The layered niobium oxysulfide was synthesized by the heat treatment of K4Nb6O17 · 3H2O layered oxide in the mixture of H2S/N2 gases. The layered oxysulfide had the large platelike shape, and the total ratio of compound was estimated KxNbS2-yOy (The number of x was from 0.2 to 0.4, y was from about 0.5 to 1.0). According to the XPS measurement, the oxidation state of Nb was estimated for +2, +4, +5, and oxidation state of S was -2. It was confirmed that the layered oxysulfide has ion exchange, and intercalation capabilities as proton exchange reactions take place in H2SO4 solution and bulky amine molecules can be intercalated in an amine solution. INTRODUCTION Layered oxides are composed of repeating guest species and host layers, which have the two-dimensional metal oxide layers. The ion exchanges [1, 2], pillaring [3, 4], intercalation [5, 6] properties are the main features of these materials. Layered oxides, which appear to have some interesting properties, are easily fabricated according to the combination between the host layers and the guest species. Oxysulfides are very interesting materials as they possess features of both oxide and sulfide. Layered oxysulfides which have the two-dimensional oxysulfide layers are expected to be a new type of functional materials. Until now, several kinds of layered oxysulfides have been reported [7-9]. We have developed a method which can synthesize the layered oxysulfide in several hours by heat-treating the layered oxide in the presence of H2S. This method is not only able to produce a layered oxysulfide in a short time calcination compared with the conventional method but also yields highly crystallized layered oxysulfides. In this present study, we report a new method for the synthesis of layered oxysulfides by sulfurization of the niobate layered oxide under the heat-treatment in the presence of the mixture of H2S/N2 gases. The synthesized layered oxysulfide has the capability for ion exchanging and intercalation of the amine molecules in the interlayers. EXPERIMENT K4Nb6O17 was synthesized by conventional solid state reaction [10]. The powder was washed with ultrapure water (Milli-Q reagent water system) under ultrasonication for 60 min to remove the excess amount of the potassium reagent. The obtained powder was heat-treated in the mixture of H2S/N2 gases. The flow rate of H2S gas was about 3.2 ml/min, and N2 was 50 ml/min, and the range of temperature was from 550°C to 850°C. In order to research the intercalation properties, the final product was treated in the 2M H2SO4 under stirring for 48h to exchange the potassium ion to proton in the interlayers. The proton exchanged powder was stirred in the
tetrabutylammo
Data Loading...
