Cationic surfactant-assisted controlled calcination strategy for constructing defect-enriched MnO2 and mechanistic study of its highly efficient room-temperature catalytic oxidation of formaldehyde

CTAB-assisted synthesis and 300 ℃ calcination prepare defect-rich α-MnO 2  catalysts. • Defects efficiently boost room-temperature formaldehyde oxidation activity. • The MvK mechanism of dynamic oxygen evolution is elucidated. A cationic surfactant-assisted controlled calcination strategy was developed for the synthesis of oxygen-vacancy-rich MnO 2 catalysts for efficient room-temperature formaldehyde oxidation. By using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent followed by optimized calcination at 300℃, the synthesized MnO 2 catalyst (denoted as M-C-300) exhibits efficient room-temperature activity for formaldehyde oxidation (95.93% conversion in 120 min) and excellent reusability. Comprehensive characterization and theoretical calculations indicate that the CTAB-assisted calcination strategy effectively regulates the morphology and surface chemistry of MnO 2 . CTAB induction reduces the average particle size from 64 nm to 41 nm, while controlled calcination at 300℃ enriches defect-associated surface oxygen species and promotes oxygen activation. The combined XPS and Raman results provide indirect evidence for defect-rich surface environments, including enhanced surface active oxygen species and defect-related lattice disorder. These defect-associated sites and active oxygen species facilitate oxygen activation and formaldehyde adsorption/dissociation, thereby contributing to the high catalytic efficiency. Download: Download high-res image (203KB) Download: Download full-size image