HAADF-STEM high-resolution study of nanometric MoS2 inside mesoporous SBA-15

• One-pot encapsulation or wetness impregnation of SBA-15 with MoS2.
• Morphology and distribution of MoS2 slabs/clusters analyzed using HR STEM-HAADF.
• One-pot preparation method provides a better MoS2 slabs dispersion within SBA-15.
• One-pot preparation method shows better catalysis for toluene hydrogenation.

This paper reports on the morphology and the localization of the MoS2 nanometric phase deposited into a SBA-15 silica network, by means of high angle annular dark field imaging at high resolution into a Cs-corrected scanning transmission electron microscope. Due to the atomic resolution and to the high sensitivity to heavy elements of this incoherent mode, the size, the stacking, the morphology and the precise distribution of MoS2-based slabs or clusters were precisely characterized. It has been shown that these parameters are strongly dependent on the synthesis method used for the insertion of the sulfide phase precursors, achieved either by direct incorporation of 12-phosphomolybdic acid, H3PMo12O40, into the silica gel using a sol–gel technique or by simple wetness impregnation of this latter in SBA-15 mesoporous silica. The one-pot encapsulation method was found to provide MoS2 slabs with a better dispersion in the SBA-15 support, comparing to the classical wetness impregnation technique.

Figure optionsDownload as PowerPoint slide