Toward Pillared Metal Sulfides: Encapsulation and Rietveld Structural Characterization of the Al13O4(OH)24(H2O)7+12Cluster into MoS2and WS2

Abstract

The synthesis of [Al13O4(OH)24(H2O)12]xMS2(x=0.02–0.05,M=Mo;x=0.02–0.055,M=W) was accomplished by a precipitative encapsulation technique using single layers ofMS2. The products were characterized by powder X-ray diffraction, energy dispersive spectroscopy (EDS), thermal gravimetric analysis (TGA),27Al MAS-NMR, room temperature electrical conductivity measurements, and surface area measurements. Powder X-ray diffraction patterns show an expansion of approximately 9.9 Å.27Al MAS-NMR indicates that the cluster is intact between theMS2layers. One-dimensional electron density mapping and Rietveld refinement performed on the powder diffraction data show that the cluster is oriented with its C3symmetry axis perpendicular to the layers. The samples exhibit conductivity values from 3 to 14 S/cm. TGA shows that the cluster is completely stable to 100°C, and largely stable to 330°C. Surface area measurements suggest that the space between the clusters is not accessible.