Highly dispersed Pt clusters within ZSM-5 stabilized by alkali metal ions and Al sites for partial methane oxidation

Zeolite is an ideal material to encapsulate nanoparticles and avoid metal aggregation, but it is challenging to achieve a high degree of metal dispersion inside zeolite. In this work, the Na+ reagent was introduced to synthesize Pt@S-1 and Pt@ZSM-5 to explore the effect of Al sites and alkali metal ions on dispersion of Pt nanoparticles. The properties of four catalysts were characterized by XRD, TEM, CO-TPR, TG and FT-IR, and the effects of alkali metal ions were analyzed combined with POM test results. The introduction of a certain amount of alkali metal ions in Pt@ZSM-5 catalyst consumed part of the hydroxyl group to form stable Pt-Ox(OH)yNa active species, which further improves the stability and dispersity of platinum nanoparticles and promotes the activity of partial oxidation of methane. This stabilization strategy can be extended to other porous materials encapsulating metal nanoparticles.