Structural characteristics of selected metal oxides used for the catalytic pyrolysis of sunflower oil

•Metal oxide catalysts are used for catalytic pyrolysis of sunflower oil.•Structural characterization of the catalysts was done before and after use.•V2O5 showed better performance compared to ZnO and Co3O4.

Structural features of metal oxides are the primary motives for utilizing them in a number of reactions and hence, investigation of catalyst structure–performance relationship is essential. This study deals with the morphological characterization of the catalysts used (Co3O4, V2O5 and ZnO) for the catalytic pyrolysis of sunflower oil for biofuel production. Also, the % organic liquid product (OLP) and fractional distillates obtained for different catalysts were analyzed. The best catalytic activity was observed with V2O5 and it was found to give higher OLP yield and gasoline like fraction. Scanning electron microscope (SEM) images of the catalysts were analyzed to determine the structural modifications of the catalysts during the reaction. The Co3O4 particles attained irregular shapes after use whereas marginal structural changes were observed for ZnO. The most fragile portion of the V2O5 particles was found to be partially eliminated upon use. FTIR analysis revealed the presence of aliphatic esters and derivatives of esters in the synthesized OLP and its gasoline fraction. The properties such as density, specific gravity, kinematic viscosity, flash point and higher heat value of the product were within the limits of ASTM D6751 (B100) standards.