A SiO2-pillared manganese titanate (SiO2-MTO) with layered structure, which has a surface area as large as more than 700 m(2)/g, effectively catalyzed the NH3 oxidation with high selectivity to N-2, The H-2 temperature-programmed reduction results suggested that the manganese ions in SiO2-MTO were in an oxidation state of +3 even in the absence of either Rb+ or C10H21NH3+ ions as a charge-balancing cation, The observed high selectivity to N-2 is attributable to oxygen vacancies associated with Mn3+ ions in the layer.