Abstract/Summary

Formaldehyde, one of important pollutants in the indoor air, has received increasing attention due to damage to human health. To mitigate formaldehyde pollution, MnCeOx mixed oxides were synthesized by solvothermal method with different solvents and complexing agents, including water or ethanol, and citric acid or glycol, and these catalysts were investigated to catalytic oxidation of formaldehyde at ambient temperature under a real indoor environment, as a super low concentration of indoor formaldehyde (1.0 ± 0.5 mg/m3) and the air under static condition. The result indicated that the MnCeOx catalysts prepared with ethanol exhibited higher activities than samples synthesized with H2O. Structure and performance analysis by BET, XRD, SEM, TEM, TG, Raman, XPS, H2-TPR, and O2-TPD displayed that the MnCeOx oxides synthesized with ethanol (instead of using water) greatly promoted the structure and reducibility, resulting in a high activity for HCHO degradation. More than 90% conversion for HCHO degradation was finished at 36 h and no deactivation could be detected by a series of tests. More importantly, the MnCeOx oxides supported by an increasing of Ag exhibited the increased activity. Promoting effect of Ag over the MnCeOx oxides indicated a strong interplay between Ag and MnCeOx greatly affected the property of Ag/MnCeOx catalysts. The HCHO concentration could be decreased to less than 0.08 mg/m3 at 24 h over 2.0 wt%Ag/MnCeOx (E/G). The performance improvement was ascribed to the high reducibility and high distribution of metallic silver, which could increase the surface active oxygen species and improve the oxygen mobility, and also could weaken the surface Mn–O bond.