Manganese oxides are prominent candidates for the catalytic oxidation of volatile organic compounds (VOCs) or ambient decomposition of O3 individually. Here, we compared various preparation methods to create a defect-enriched Ag–MnO x nanocomposite that exhibits a remarkably multifunctional activity in VOC combustion and ozone decomposition. Ag+ ions were well-dispersed in the microtunnels of Ag–MnO x -H via hydrothermal replacement of the original K+ ions; this catalyst’s benzene combustion efficiency (T 90% = 216 °C at a space velocity of 90 000 mL h–1 g–1) was comparable to that of typical noble metal catalysts. Moreover, the decomposition of ozone over the Ag–MnO x -H catalyst (space velocity = 840 000 mL h–1 g–1) under a relative humidity of 60% was above 90%, indicating that it is a promising material for ozone elimination in practical application. The local structure results indicated that silver incorporation via the hydrothermal method facilitates the formation of nonstoichiometric defects in the MnO x matrix. The large number of active oxygen species related to O vacancies appeared to play critical roles in VOC combustion; moreover, the oxygen vacancies originating from O defects were also critical in O3 abatement. This work provides multifunctional catalysts for VOC combustion and ambient O3 decomposition and may assist with the rational design of MnO x catalysts for application in various conditions.

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