A New Approach for the Preparation, Exfoliation, and Intercalation Properties of Niobium Layered Sulfide Material

We have developed the new process that can synthesize a layered niobium sulfide under heating a layered oxide with H₂S/N₂ gas mixture. It was confirmed that K_0.34(H₂O)_xNbS₂ was obtained as a single phase and high crystallinity under heating K₄Nb₆O₁₇ · 3H₂O with the gas at 750°C for 10 h and washing with distilled water. The layered sulfide had the large plate‐like shapes that have 50 µm wide length on average. Potassium ions in the interlayer of K_0.34(H₂O)_yNbS₂ could be exchanged to hydronium ions by stirring 2M H₂SO₄. It was also confirmed that tetrabutylammonium could intercalate in interlayer of proton exchanged form. In addition, colloidal solution was obtained after ultrasonication of proton exchanged form. According to the AFM image, the thickness of sulfide nanosheets had 4.2 Å, which roughly corresponded with the thickness of NbS₂ single layer.

Keywords:

• niobium layered sulfides
• ion exchange
• intercalation
• exfoliation

Acknowledgments

This work was supported by the Core Research for Evolutional Science and Technology (CREST) program of the Japan Science and Technology Co. (JST), and a Grant‐in‐Aid for Scientific Research (No. 15350123) from the Ministry of Education, Culture, Sports, Science, and Technology.