Analysis Of The Surface Texture Modifications Of Some Catalyst Oxides By Foreign Salt Additives

The influence of foreign salt additives, namely (NH2)2CO and NH4NO3, on the surface texture and pore structure of V2O5 and NiO , produced by thermal decomposition of their precursor compounds of NH4VO3 and Ni(N03)2.6H20, has been investigated. Thermal behaviour of oxide precursor compounds as well as additive salts (pure and impregnated into the oxides) was explored by thermal analysis. Accordingly, the calcination products of the additive-free and additive-containing oxides were obtained at the appropriate temperatures. The results of texture assessment, thermal analyses (DTA and TG) and X-ray differeraction agreed and showed that pores modified. An impregnation procedure using one molar of the salt additive to one molar of V2O5 and NiO , resulted in a marked increase of surface area and pore modification. Urea additive, was found to improve notably the surface area and porosity of V2O5 and NiO than ammonium nitrate additive. This was correlated with the structural modifications conceded by the material bulk during thermal treatment, due to the widening of pores.