Synthesis and characterization of a novel mesoporous Mn - Organophosphate molecular sieve

Abstract

A novel mesoporous Mn - organophosphate was synthesized for the first time. It is characterized by several physicochemical techniques. Small angle X-ray diffraction analysis shows the first peak in 2.5° with 39 A° pore width. Elemental analysis shows that the composition is [(C12H 23N)3PO]40Mn. Scanning electron microscopic picture shows the flag morphology with 1-15 μm particle size. Thermogravimetry/Differentaial thermal analysis shows almost 80% exothermic weight loss. Nitrogen adsorption isotherm shows type III with 300 m 2/g BET surface area. Fourier transform Infrared spectroscopic analysis shows that the framework vibrations are comparable to other well known silica mesoporous materials. Electron spin resonance spectroscopic analysis shows the absence of hyperfine splitting indicates the presence of Mn 3+ species. Ultraviolet - visible spectroscopic analysis shows that most of the Mn is in tetrahedral co-ordination beside small square pyramidal species. A plausible synthesis mechanism also proposed.