Integration of Ultrasmall Pt Clusters With Silanol Groups in Pure Silica Zeolites for Robust Formaldehyde Oxidation

Formaldehyde (HCHO) is a major indoor air pollutant that poses serious health risks. Catalytic oxidation of HCHO to CO₂ and H₂O at room temperature offers an efficient solution. Supported Pt nanoparticles are the most efficient catalysts, but challenges such as high cost and water resistant, limit their widespread application. Herein, we employ a ligand-protected direct hydrogen reduction strategy to encapsulate ultrafine Pt clusters within hydrophobic silicalite-1 zeolite. C_s-corrected scanning transmission electron microscopy, x-ray absorption, and solid nuclear magnetic resonance measurements confirmed that the Pt clusters are stabilized within zeolite channels by adjacent silanol groups. The optimized Pt@S-1-400H catalyst achieved complete HCHO removal at room temperature, with even low Pt loading of 0.1 wt%, affording a high specific activity of 171.9 mol_HCHO·mol_Pt ^-1·h^-1, representing the top level among all state-of-the-art Pt-based catalysts. Significantly, the hydrophobic nature of silicalite-1 ensures excellent water resistance and long-term stability for the Pt@S-1-400H catalyst. In situ infrared spectroscopy reveals that silanol sites facilitate HCHO adsorption and the formation of formate intermediates. The synergistic effect between Pt clusters and adjacent silanol sites enhances the HCHO oxidation performance. The simple and cost-effective approach, combined with its excellent activity and stability, holds significant potential for effectively eliminating indoor pollutants in practical applications.