Room Temperature Synthesis of Zinc Pyromellitate Complex and its Application as a Precursor for Nano-ZnO Formation
Bukunola K. Oguntade
*
Department of Chemistry, Rhodes University, Grahamstown, 6139, South Africa and Department of Science Laboratory Technology, The Federal Polytechnic, Ilaro, Ogun State, Nigeria.
Gareth M. Watkins
Department of Chemistry, Rhodes University, Grahamstown, 6139, South Africa.
*Author to whom correspondence should be addressed.
Abstract
Nano-sized ZnO was synthesized using a tetranuclear Zn(II) pyromellitate salt with the general formula [Zn4(H2B4C)2.5(OH)3(H2O)5] as a precursor. The precursor was synthesized under room temperature precipitation technique using zinc acetate dihydrate and 1,2,4,5-benzenetetracarboxylic acid in a molar ratio of 2:1 in water-methanol mixture (1;1 v/v) at the natural pH of the reaction mixture. The composition of the complex was determined by the elemental analysis (EA), Fourier Transform Infra-red Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Powder X-ray Diffraction (PXRD), Braunauer-Emmett-Teller (BET) Analysis and Thermogravimetry (TG) Analysis, The end product of the thermal decomposition of the precursor at 400 °C and 800 °C is the ZnO, confirmed by XRD. The effect of calcination temperature on the prepared ZnO showed that the crystallite size of the nano-ZnO increases from 16 nm at 400 °C to and 23 nm at 500 oC respectively.
Keywords: Thermal decomposition, room-temperature precipitation method, nano-ZnO