The Catalytic and Adsorptive Synergistic Effect of Oxygen-Vacancy-Rich MnOx/C Catalysts for HCHO Oxidation at Room Temperature

Indoor formaldehyde (HCHO) pollution has attracted extensive attention and shows a carcinogenic effect on humans. However, removal of HCHO still faces the issues of low activity and high-loading noble metals. Herein, we combined catalysis and adsorption into the MnO x /C composite catalysts with abundant oxygen vacancy (V O ), which were prepared through a facile in situ synthesis approach between fructose and KMnO 4 . With the addition of fructose during preparation, the as-achieved MnO x /C- y catalysts not only increased oxygen vacancies but also provided adsorption sites, which showed excellent activity and durability for mineralizing HCHO to CO 2 and H 2 O at room temperature. The HCHO removal efficiency was up to 97.3% for 100 ppm of HCHO and 89.7% for 0.66 ppm of HCHO. Furthermore, no significant downward trend was detected even after four cycles. The rich Mn 3+, surface oxygen vacancies, and reactive oxygen species were the main factors for HCHO removal. In situ DRIFTS study revealed that surface −OH accelerated the conversion and oxidation of the formed intermediates.