A new approach for the synthesis of layered niobium sulfide and restacking route of NbS2 nanosheet

Abstract

We have developed a new process for the synthesis of a layered niobium sulfide that involves heating K4Nb6O17 center dot 3H(2)O with a H2S/N-2 gas mixture. It was confirmed that heating the starting layered oxide at 750 degrees C for 10 It under the as flow yielded a highly crystalline, 9 single-phase K-0.34(H2O)(0.7)NbS2. The layered sulfide slabs had a large plate-like shape. Potassium ions in the interlayer of K-0.34(H2O)(0.7)NbS2 could be exchanged with protons by stirring in 2M H2SO4. It was found that the proton in the proton-exchanged form can be easily exchanged with other cations. The proton-exchanged form was exfoliated into NbS2 nanoshects by ultrasonication in water. According to the atomic force microscopy (AFM) images, NbS2 nanosheets had a thickness of around 4 angstrom, which roughly corresponded to the thickness of a single NbS2 host layer. NbS2 nanosheets could be restacked with the intercalation of Eu3+ or tetrabutylammonium ions by an electrostatic self-assembly deposition (ESD) technique. (c) 2007 Elsevier Inc. All rights reserved.