Thermal and hydrothermal stability of siliceous Y zeolite and its application to high-temperature catalytic combustion

Siliceous Y zeolite (SiO2/Al2O3>150), prepared through repeated dealumination with SiCl4 and steam, displays high thermal and hydrothermal stability. After aged at 1200 degrees C for 4 h, siliceous Y zeolite shows specific surface area as high as 510 m(2)/g. Even steamed at 1000 degrees C for 4 h, it still keeps its framework perfectly. Palladium on siliceous Y zeolite shows a bit less oxidation activity of n-hexane than that on lanthanum-modified alumina. It exhibits good capability in resisting heat but poor resistance to steam. When palladium is supported on SY-A carrier, in which 12.3% alumina has been loaded on siliceous Y zeolite, the catalyst shows higher oxidation activity than Pd/La-Al2O3 even heated or steamed at 1000 degrees C for 4 h. Its excellent resistances to heat and steam make it a promising catalyst for high-temperature catalytic combustion. (C) 1999 Elsevier Science B.V. All rights reserved.