Ionic liquid assisted Synthesis and Characterization of metallic Molybdenum and Molybdenum oxide nanoparticles

Abstract

Nanostructured Mo and MoO3 colloidal dispersions have been obtained reproducibly through reduction of ammonium molybdate by sodium borohydride in ionic liquids When NH4 6Mo7O24 4H2O is reduced by NaBH4 in both 1-ethyl-3-methyl imidazolium dicyanamide and 1-butyl-3- methylimidazoliumdicyanamide at 180oC nanostructured MoO3 formed as the major phase The XRD pattern confirmed the crystalline nature of the material The most representative reflections of MoO3 JCPDS 47-1081 were indexed in monoclinic crystal system space group P2 1 c 14 Y-unique The average mean diameter of 53 8nm was calculated using Debye-Scherrer equation from full width at halfmaximum FWHM of 111 -311 160 -421 330 and 413 planes for material in IL EmimN CN 2 But in BmimN CN 2 the diameter was estimated to be 40 8nm When the reduction was carried out in EmimOTf and BmimOTf the products consists of metallic molybdenum and MoO3 The crystalline phase of MoO3 is rodlike and is determined to be orthorhombic space group Pbnm 62 with the cell dimensions a 3 963 b 13 856 c 3 696 Vol 203 3 Z 4 4 7096gcm-1 corresponding to MoO3 JCPDS 35-0609 The average diameter of 51 0 and 48 9nm was calculated respectively for particles in IL EmimOTf UV-Visible absorption spectra of the fraction in ionic liquid dispersed in ethanol shows that the predominant feature in the spectra is the spin-allowed ligand-to-metal charge transfer LMCT from O2- ion tiu orbital to a d0 eg orbital which is observed in the range 200-300nm centred at 212nm in the UV region This strongly indicates the presence of metallic Molybdenum with particle size less than 100nm