Effects of Si/Al ratio on the interaction of nonthermal plasma and Ag/HY catalysts

• Effects of Si/Al ratio on the interaction of plasma and Ag-supported HY zeolites.
• ESR evidence of divalent Ag cations produced by oxygen plasma treatment.
• Plasma-induced fluorescence from the excited surface of catalyst.

The effect of the silica and alumina ratio (Si/Al) in HY was studied as an important parameter that determines the catalytic activity of zeolite under plasma activation. The Ag loaded on HY was in a more oxidized state at lower Si/Al ratios and in a more metallic state at higher Si/Al ratios. A substantial drop in the relative electrical resistivity occurred when Ag was supported on the HY at a Si/Al ratio of 40. A strong relationship between the propagation of surface streamers and the catalytic activity was observed when the Si/Al ratio was changed in the following order: 2.6 > 15 > 40. The interactions of oxygen plasma and Ag-loaded HY zeolites were clearly demonstrated via electron spin resonance (ESR) measurements of divalent silver (Ag2+) and Fe3+ cations and plasma-induced fluorescence of Ag-cation clusters.

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