Low‐Temperature Methane Abatement by Catalytic Ozonation Over Metal‐Modified SSZ‐13 Catalysts

The catalytic ozonation has been extensively studied for the abatement of volatile organic compounds (VOCs). The catalytic oxidation of low‐concentration methane (CH 4 ) suffers from the issue of low conversion efficiency at low temperatures (< 300°C), while the catalytic ozonation is expected to effectively address this issue by feature of the strong oxidizing property of ozone (O 3 ). Therefore, the CH 4 catalytic ozonation performance of five SSZ‐13 zeolites loaded with Pd, Fe, Ni, Mn, and Cu (2.5 wt.%) and the various characterizations (such as XRD, BET, XPS, and H 2 ‐TPR) of catalysts was systematically investigated in this study. The results indicated that the Pd/SSZ‐13 catalyst exhibited the best catalytic oxidation activity with a CH 4 conversion rate of over 90% at 435°C. however, the Fe/SSZ‐13 catalyst had the best low‐temperature catalytic ozonation performance, achieving a methane conversion rate of 56% at 200°C. According to the characterization results, the O 3 ‐pretreated Fe/SSZ‐13 catalyst possessed a higher surface adsorbed oxygen concentration, a higher Fe 3+ /Fe 2+ ratio and a lower redox temperature compared to the fresh Fe/SSZ‐13 catalyst. In‐situ Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) detected distinct the O 3 and superoxide (O 2 − ) adsorption peaks on the Fe/SSZ‐13 surface. These results suggests that O 3 adsorbs and dissociates into highly active oxygen species on the Fe/SSZ‐13 catalyst surface, leading to a significant improvement in the low‐temperature CH 4 ozonation reaction.