What is HY Zeolite?

HY zeolite is the proton-exchanged H-form of Y zeolite — the material produced when Na-Y is ion-exchanged with ammonium (NH₄⁺) and calcined to decompose NH₃, leaving behind H⁺ cations that create strong Brønsted acid sites within the FAU framework. It retains the 12-membered ring pores (~7.4 Å) and ~12 Å supercages of the parent Y zeolite while delivering the highest acid-site density available in a commercial FAU zeolite.

HY is the acidic counterpart to dealuminated USY. Where USY sacrifices acidity for hydrothermal stability through steam dealumination, HY preserves maximum framework aluminium content and therefore maximum Brønsted acidity. This makes HY the preferred choice when activity matters more than stability.

HY zeolite is supplied with SiO₂/Al₂O₃ ratios from 5 to 80+, Na₂O controlled below 0.1 wt%, and powder or extrudate forms. For detailed grade selection, see the HY product hub. For the acidity-stability trade-off, see HY vs USY.