Y single atoms boost MnO2 for efficient ambient formaldehyde catalytic oxidation

Abstract

Formaldehyde (HCHO) is a hazardous indoor air pollutant requiring effective mitigation. Room-temperature catalytic oxidation is promising for its energy efficiency and ability to convert HCHO into harmless products. Manganese dioxide (MnO₂) is a potential catalyst but exhibits low activity at ambient temperatures due to energy barriers in dehydrogenating intermediates. This study introduces Y single-atom-decorated MnO₂ as an efficient catalyst for HCHO oxidation. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) and X-ray photoelectron spectroscopy (XPS) confirmed Y atom dispersion. Additionally, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), solid-state ¹H nuclear magnetic resonance spectroscopy (¹H NMR) and density functional theory (DFT) revealed the mechanism by which Y atoms enhance HCHO oxidation. The results show that Y₁/MnO₂ significantly outperforms pristine MnO₂ in CO₂ yield, with a prolonged high-efficiency period and substantially higher steady-state CO₂ production. Y single atoms (SAs) generate reactive oxygen species via oxygen vacancies formation in MnO₂, leading to extended high efficiency. Additionally, Y SAs enhance the catalyst’s proton affinity, facilitating dioxymethylene (DOM) dehydrogenation and improving overall HCHO oxidation efficiency. This work offers a new perspective for designing efficient catalysts for indoor air purification.