Ordered mesoporous CoOx/MCM-41 materials exhibiting long-range self-organized nanostructured morphology

A novel class of nanostructured silicious materials of MCM-41 type containing cobalt, CoOx/MCM-41, and exhibiting remarkable long-range self-organized morphology has been developed. The method of synthesis is a one step procedure and includes the use of poly-acrylic acid, complexed with CTAB by a zip-type mechanism, as a backbone of the structure. On the external surface of this mesostructure, hydrolysis of TEOS and Co(NO3)2 takes place at various pH values. The loading of cobalt (9 < Si/Co < 37) in the final solid can be controlled by the pH values at which the material is isolated in the range 5.5 < pH < 9.5. The isolated mesostructures, after drying (80 °C), as well as the resulting mesoporous solids after calcination (600 °C), exhibit remarkable self-organized morphology of the order of μm. In XRD, both the dried mesostructured as well as the calcined solids, exhibit typical patterns of MCM-41 type, which are blurred as the amount of cobalt increases. The surface area of those nanostructured mesoporous solids CoOx/MCM-41 was determined in the range 910–1250 m2/g by nitrogen porosimetry and their pore volume in the range 0.7–0.9 cm3/g. The pore diameter D was found to be around 3.1 nm while the pore anisotropy b = L/D, where L—the length of the pores, was determined in the range 15–380 depending on the sample.