Significant enhancement of catalytic activities of manganese oxide octahedral molecular sieve by marginal amount of doping vanadium

Vanadium doped hollandite-type manganese oxide octahedral molecular sieve (OMS-2) was synthesized by a simple hydrothermal route. The results of catalytic tests showed that marginal amount of doping vanadium had greatly enhanced catalytic activities of OMS-2 not only in low-temperature complete oxidation of formaldehyde at 140 °C but also in high-temperature complete oxidation of methane at 450 °C. The results of XPS, HRTEM and H2-TPR measurements revealed that the enhancements of the catalytic activities primarily resulted from the increase of surface defect sites regardless of reaction temperatures and nature of reactants, rather than reducibility and average oxidation state of manganese.