Facile Synthesis of Amorphous MnO x Catalysts for Efficient Ozone Elimination in Domestic Refrigerators

Amorphous manganese oxide catalysts, aimed at efficient ozone removal in refrigerators, were synthesized using a simple redox method. Factors like crystallinity of structure, textural properties, and Fe doping significantly affect the catalyst's performance. The Fe-doped KMF-250 showcased outstanding ozone decomposition capabilities, efficiently eliminating 10,000 ppb of ozone at an average rate of ca. 13.3 , under conditions of 6 °C and 36% relative humidity in a refrigerator chamber (144 L). Moreover, this catalyst exhibits extraordinary stability, outperforming existing commercial catalysts in terms of both durability and efficiency. The incorporation of even a minimal amount of Fe (0.84 wt%) considerably raised the amount of low-valence Mn, resulting in more crystal defects and oxygen vacancies. The existence of Fe in MnOx was also found playing an important role in promoting the desorption of the oxygen species and enhancing the oxygen mobility to generate oxygen vacancies, both of which contribute to the quick recovery of the catalyst. The catalyst's large specific surface area, combined with optimal Fe doping, are crucial for its superior catalytic performance. This research delivers a potent MnOx catalyst suitable for ozone removal in refrigerators and viable for mass production.