Application of MnCeOx supported on palygorskite and Al(OH)3 for HCHO oxidation: Catalytic performance and stability

Abstract

Indoor formaldehyde (HCHO) is an important air pollutant, while it is very difficult to reduce HCHO to low-level (e.g. <0.08 mg/m3). Catalytic oxidation at ambient temperature has been increasingly recognized as one of the important methods to mitigate HCHO pollution due to its good effectiveness, stability, and recyclability. To further improve the activity of catalytic oxidation, this study develops the integrated MnCeOx catalysts supported on palygorskite (Pal) and aluminium hydroxide (Al(OH)3). Our results indicate that the synergistic interaction in MnCeOx through the oxygen transfer mechanism from the oxygen reservoir CeO2 to MnOx significantly improves the activity. Pal, Al(OH)3, etc. were applied as the supports with a focus on their dispersion, microstructure, strength, and relative role. MnCeOx can be anchored on the surface of Al(OH)3 with high dispersion. With the integrated catalyst, HCHO concentration decreases from 1.012 to 0.086 mg/m3 within 48 h. Higher oxidation activity of MnCeOx powder may be ascribed to the amount of active components on the surface. The incorporation of ZSM–5 and activated carbon can improve the adsorption of HCHO, and all integrated catalysts exhibit stronger activities, with HCHO being degraded to the level lower than 0.08 mg/m3. Meantime, the samples exhibit good stability and strength (20.2 MPa) without obvious decrease over five consecutive stability experiments.