Abstract: Formaldehyde, as a typical indoor pollutant, has carcinogenic properties. Purifying formaldehyde is important for human health. At room temperature, using catalysts to degrade formaldehyde into CO₂ and H₂O has become the preferred solution for indoor formaldehyde purification. The δ-MnO₂ is prepared by oxidation-reduction method. The appearance and structure of δ-MnO₂ are analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Finally, the δ-MnO₂ is loaded to the aluminum honeycomb panel to form the catalyst module. And the formaldehyde removal performance is compared with the activated carbon module in the 30m³ test chamber. The results show that the δ-MnO₂ has many defect sites, which are conducive to the storage and transfer of reactive oxygen species. The δ-MnO₂ has 2D layer structure, which is conducive to the adsorption of formaldehyde on the surface and diffusion to active sites. The catalyst module load δ-MnO₂ 0.065 g/cm³, the CADR value is 171m³/h. The formaldehyde removal performance of the catalyst module is much higher than the active carbon module with the same loading capacity. After multiple repeated experiments, the δ-MnO₂ catalyst module maintains formaldehyde purification performance. And the cumulative purification amount (CCM) of formaldehyde exceeds 42000 mg, demonstrating a long-term formaldehyde purification life.

Key words: Formaldehyde, δ-MnO₂, Oxidation-reduction method, Room temperature catalytic