Studies on the heterogeneous reaction between $Zno-(NH_4)_20.4MoO_3$

Abstract

The formation of $ZnMoO_4$ and $Zn_3Mo_2O_9$ were studied using x-ray diffraction analysis, IR, DTA-TG, electrical conductivity, elemental analysis and surface acidity measurements. The concentration of acidic sites on the surface of $MoO_3-ZnO$ system was studied and the results illustrated a maxima at ZnO -$Mo_3$(20-80%) at a calcination temperature of 600°C. The stability of the $ZnMoO_4$ and $Zn_3Mo_2O_9$ phases were studied at 600 and 750°C. The $Zn_3Mo_2O_9$ phase is stable at lower temperature and disappears at temperatures above - 700°C