Comprehensive analysis of the transition metal oxide nanomaterials role as catalysts in the low-temperature oxidation of adsorbed nC7-asphaltenes

• Five transition metal oxide nanomaterials were successfully synthesized. • All materials showed affinity toward the adsorption of asphaltenes. • An experimental correlation between the affinity constant (Langmuir model) and the activation energy for asphaltene oxidation was achieved. • The oxygen mobility from the bulk of the materials was proved to be a relevant factor for the oxidation of the heavy oil catalyzed by the nanomaterials. Fe 2 O 3 , V 2 O 5 , NiO, MnO 2 , and MoO 3 nanomaterials were synthesized and used as adsorbents as well as catalysts in low-temperature oxidation of asphaltenes. The acidity of the metal cations seems to be the predominant factor improving adsorption capability. Further, RTO, TGA and DSC techniques evinced catalytic properties for all the studied materials in the oxidation of asphaltenes. Particularly, a correlation between the adsorption affinity and the activation energy in the combustion process was experimentally evidenced for Fe 2 O 3 , MnO 2 , and MoO 3 materials. Thus, the asphaltenes-surface interaction plays a key role for adsorptive and oxidative treatment of asphaltenes. Transition metal oxide crystalline phase and its corresponding redox properties proved to be relevant parameters for promoting oxygen addition reactions in the low temperature oxidation process.