Insight into ventilation air methane combustion of ultralow sub-nanometer palladium catalyst within the MFI zeolite

Abstract

Methane's complete catalytic oxidation process has been widely studied, but efficient catalytic oxidation of low-concentration methane (≤0.75 %) remains a crucial problem in the coal chemical industry. How to prevent the sintering deactivation of the active component in Pd-based catalysts and achieve efficient and stable operation of sub-nanometer catalysts remains challenging. Here, we utilize the interaction between amine ligands and Pd nanoparticles to stabilize and encapsulate the Pd particles within the pores of a molecular sieve carrier, effectively promoting the high dispersion of Pd particles. By leveraging the low acidity, high hydrophobicity, and high hydrothermal stability of the zeolite carrier, the Pd@S-1 catalyst exhibits excellent activity and stability in the catalytic oxidation of methane at low concentrations. Finally, density functional theory is employed to investigate the reaction mechanism of low-concentration methane during the catalytic process. Encapsulating the active metal component in zeolite to improve catalytic activity and stability provides a theoretical basis and direction for preparing complete oxidation catalysts for low-concentration methane.

Keywords: Catalytic mechanisms; Low-concentration methane; Pd cluster; Silicalite-1 zeolite; Sub-nanometer catalysts.