Metal organic frameworks derived manganese dioxide catalyst with abundant chemisorbed oxygen and defects for the efficient removal of gaseous formaldehyde at room temperature

• One-step redox method between Mn-MOF and KMnO 4 was proposed to prepare MnO 2 catalysts. • The MnO 2 -M catalyst with optimal pore structure features abundant ROS and Mn vacancies. • High active ROS and vacancy defects greatly promotes the HCHO catalytic activity at 25 °C. The low-concentration HCHO removal at room temperature is still a challenge in the indoor air purifying. Manganese dioxide catalyst (MnO 2 -M) derived from metal-organic frameworks (MOF) was synthesized via facile in-situ redox reaction. The obtained MnO 2 -M catalyst displayed superior activity and stability for low-concentration HCHO removal, reaching ~95% for 1.0 mg/m 3 of HCHO under dynamic test mode and degrading 93.1% for 1.0 mg/m 3 HCHO in 3 h under static test mode at room temperature. Moreover, the enhanced activity of MnO 2 -M could be attributed to the abundant chemisorbed oxygen species, numerous Mn-vacancies and proper pore size distribution. More crucially, the chemisorbed oxygen species on the MnO 2 -M could be rapidly activated by the transferable electrons and vacancies, thus significantly promoting the formation of reactive oxygen species and HCHO decomposition. The present work provides a new strategy to develop efficient catalyst for indoor air purification.