Hazara University, Pakistan
Title: Pb3O4/ZrO2 Nanocomposite Synthesized from Single Source Molecular Precursor Employing Sol Gel Method
Dr. Hameed Ullah completed his Ph. D from the University of Saarland, Germany under the supervision of Prof. Dr. Dr. h.c. Michael Veith. He has worked upon the synthesis of single source molecular precursors which have been used in MOCVD process for preparation of nano thin films. After completion of Ph. D, he has joined Hazara University, Pakistan, as Assistant Professor. He has published numerous articles in peer reviewed journals and presented his research work in various international conferences in different countries. He has many M. Phil and Ph. D students under supervision working upon the synthesis, characterization and applications of nanomaterials. He is serving as a reviewer of different international journals.
Lead Oxide  and Zirconium Oxide  are well known for their catalytic applications. However, the individual oxides have shown many deficiencies  which could be hindered successfully by adding up them together. The coupling of dissimilar oxide introduces novel characteristics to the fascinating parameters of the individual oxides. However, the enhanced characteristics could only be achieved if the microstructure is controlled at atomic level. To do so, the role of precursor is very important. Therefore, a single source molecular precursor (SSP) is designed and developed for the synthesis of lead oxide/zirconium oxide nanocomposite. The heterometal-pseudo-alkoxide, [(bpy)Cl2Pb(μ- OtBu)2ZrCl2(THF)2], SSP was synthesized under nitrogen environment and structurally characterized by 1H-NMR and IR spectroscopy. The thermal decomposition pattern of the SSP was established by TGA analysis (Scheme). Scheme 1 The structurally characterized SSP was hydrolyzed at pH = 9 (employing sol-gel method) and the resulting powder were sintered at 450°C for 4 hours. The XRD pattern of the hydrolyzed product gives no significant peaks indicating that the material is amorphous (Figure 1(a)). However, the crystallinity is improved upon sintering and significant peaks are observed in the XRD pattern of post-sintering sample corresponding to that of lead oxide ((Pb3O4)) and ZrO2 (Figure 1(b)). The morphological investigations (using SEM technique) of pre- and post-sintering powder show elongated (rod like) nanoparticles. The particles are agglomerated and thicker of the presintering sample while clearer and thinner of the post-sintering. The elemental compositions of the pre- and post-sintering powder are confirmed by EDX spectroscopy. The EDX spectrum of the pre-sintering sample shows a weak peak for chlorine as impurity. However, the postsintering material is free of any sort of impurity. The Pb-O and Zr-O bonds are confirmed by IR spectroscopy which gives clear vibrational bands in the range of 600 – 400 cm-1.