Selective catalytic oxidation of methanol on Pt-modified Cu/SSZ-13 zeolites: A strategy to change the catalytic performance by impregnation sequential

The use of methanol as an alternative fuel for marine diesel engines increases unregulated CH ₃ OH emissions. A series of Pt-modified Cu/SSZ-13 catalysts were prepared using different impregnation method, which selectively catalyzed oxidation of CH ₃ OH (CH ₃ OH-SCO) to CO ₂ and H ₂ O. Activity tests showed that Cu/Pt/SSZ-13 catalyst (Pt impregnated first, followed by Cu) displayed exceptional CH ₃ OH-SCO performance, achieving 100 % methanol conversion at 150 °C with negligible CO and HCHO byproduct formation (< 5 ppm) across the tested temperature range. Additionally, Cu/Pt/SSZ-13 catalyst exhibited excellent SO ₂ resistance and high synergistic activity for simultaneous CH ₃ OH and NO _x removal. Characterization results demonstrated that Cu/Pt/SSZ-13 catalyst exhibited larger pore size, higher specific surface area, abundant strong alkaline site density and elevated surface-adsorbed oxygen (O _ads ) proportion. It was originated from the preferential introduction of Pt and subsequent doping of Cu enhanced the synergistic interaction at the interface of PtO _x and CuO species, which facilitated the rapid migration of reactive oxygen species, thus accelerating the methanol dehydrogenation and deep oxidation. In-situ DRIFTS results indicated that Cu/Pt/SSZ-13 inhibited the deposition of formate while promoting the rapid conversion of intermediates such as formaldehyde and formic acid to CO ₂ .