Nanofibrous SUZ-4 loading Pt used for selective catalytic reduction of NO_x by hydrogen

摘要

Nanofibrous SUZ-4 zeolite (NF) was synthesized for preparing the Pt/HSUZ-4 catalyst used in the selective catalytic reduction of NO_x by hydrogen (H2-SCR). The seed dissolution during the crystallization played an important role for the nanofibrous SUZ-4 formation. It was found that the zeolite NF is oriented along the 10-ring channels, and it has much more Bronsted acid sites on its external surface compared with general SUZ-4 zeolite. Consequently, Pt primarily existed as the well-dispersed particles (~5 nm) on the NF external surface for the Pt/NF catalyst prepared by impregnation. In comparison with 0.1 wt.% Pt/HZSM-5 as well as general 0.1 wt.% Pt/HSUZ-4, the 0.1 wt.% Pt/NF catalyst gave much higher activity and N2 selectivity in the H2-SCR. For identifying the Pt ions in SUZ-4 zeolite channels, the band at 1652 cm~(-1) ascribed to nitrous species adsorbed on the ions was proposed.