Mo-V-Te-Nb oxide catalysts: Reactivity of different oxygen species in partial and deep oxidation

• Two forms of surface oxygen species were found on Mo-V-Te-Nb oxide catalysts.
• Weakly bonded adsorbed oxygen participates in deep oxidation, while lattice oxygen takes part mainly in partial oxidation.
• Weakly bonded oxygen concentration decreases in series: Me5O14 > M2 > M1 and thus selectivity towards partial oxidation increases.

Isotopic oxygen exchange on the surface of Mo-V-Te-Nb oxide catalysts was studied. Catalyst samples contained more than 95% of (i) orthorhombic phase M1, (ii) pseudo hexagonal phase M2, or (iii) layered phase with structure Me5O14 (Me – Mo, V, Nb). Two forms of exchangeable oxygen were found on the surface, i.e. strongly bonded lattice oxygen and relatively weakly bonded adsorbed oxygen. According to in situ studies with isotope 18O adsorbed oxygen leads to deep oxidation products, while lattice oxygen participates mainly in the partial oxidation processes. Weakly bonded oxygen concentration decreases in series: Me5O14 > M2 > M1 and thus selectivity towards partial oxidation increases.

Figure optionsDownload high-quality image (71 K)Download as PowerPoint slide