Fabrication of amorphous MnO2/MnC2O4 heterostructures for efficient ozone decomposition

Amorphous MnO 2 /MnC 2 O 4 heterostructures was constructed. • MnO 2 -2 possesses abundant oxygen vacancies, heterointerfaces, and a large surface area. • The MnO 2 -2 achieved 94 % O 3 removal at a high WHSV of 1,440,000 mL/(g·h) with cycling durability over five cycles. • The heterostructures facilitate rapid electron transfer and relieve the accumulation of deactivating intermediate oxygen species. • The strategy reduced wastewater by 67 % and enhanced space-time yield by 37 %. Constructing synergistic active sites in manganese dioxide (MnO 2 ) catalysts has attracted increasing attention as an effective strategy to improve ozone decomposition. Herein, we report a composite structure of amorphous MnO 2 /MnC 2 O 4 heterostructures as an efficient synergistic catalyst for ozone decomposition. Structural and surface analyses reveal the formation of a multiphase composite featuring high-density oxygen vacancies, abundant heterointerfaces, and a large specific surface area. In situ diffuse reflectance Fourier transform infrared ( in situ DRIFT) spectroscopy reveals a synergistic mechanism: amorphous MnO 2 promotes ozone adsorption and activation, while the heterointerface accelerates electron transfer to prevent the accumulation of deactivating oxygen species. Benefiting from this synergy, the catalyst achieves 94 % conversion under an ultra-high weight hourly space velocity (WHSV) of 1,440,000 mL/(g·h). It also demonstrates excellent performance in different scenarios, including high ozone concentrations (1000 ppmV), humidity resistance (65 % RH), cycling durability (5 cycles), and long-term stability (20 h). Furthermore, the monolithic catalyst maintains high efficiency for over 24 h. This work not only provides an effective room-temperature strategy for synthesizing active MnO 2 -based catalysts but also significantly alleviates the poisoning effect of adsorbed impurity ions on active sites, demonstrating great potential for practical application. Download: Download high-res image (629KB) Download: Download full-size image