To initiate water-promoted reaction pathways on CuMnAl catalysts to facilitate ozone decomposition under humid conditions.

Efficient catalytic ozone (O) purification under low temperature and high relative humidity (RH) conditions with optimal active sites that promotes water molecules to participate in O degradation is essential for sustainable development for human health and ecological environment. This study initiates "water-promoted" reaction pathways on cost-effective and low-toxicity manganese-based catalysts to realize efficient O purification (T ≤ 45 °C) under both dry and humid conditions through simple aging time modulations. Experimental results demonstrate that prolonging aging time transforms the CuMnAl crystalline structure from MnCO and Mn(OH) to MnO, concomitantly reducing the catalyst's electron-donating and electron-withdrawing capacities. This adjustment minimizes interactions with intermediate products, enabling 100 % O conversions at ambient temperatures (80 ppm O/air, 600,000 mL g h, 0 % RH). Conversely, reduced aging time of CuMnAl catalyst preserves higher contains of Brønsted acid sites and surface hydroxyl groups, facilitating activation of water molecules to participate in O degradation, resulting in 93 % O conversions at 45 °C (90 % RH), which improves 12 % compared to dry conditions, effectively initiating the "water-promoted" reaction pathways. Additionally, in situ diffuse reflectance Fourier transform (DRIFT) characterization elucidates seven reaction mechanisms on the CuMnAl catalyst surface, pinpointing pivotal active sites involved in water-promoted reactions. This study establishes a theoretical framework for enhancing the moisture resistance of manganese-based catalysts and offers a viable solution for purifying ozone under conditions of low temperature and high humidity.