Preparation of a silicalite/ACF composite and its catalytic activity for NO oxidation to NO2

A silicalite/activated carbon fiber (ACF) composite was prepared by a two-step method, in which nitric acid oxidation was used to incorporate hydrophilic groups to improve crystal seed impregnation and a hydrothermal process was used to grow silicalite on the ACFs. The samples were characterized by SEM, XRD and N2 adsorption. Results showed that the surface of the ACFs was covered with a silicalite layer, and the specific surface area, pore volume and average pore size of the composite were 826 m2·−1, 0.42 cm3·−1 and 0.64 nm, respectively. The catalytic activity of the ACFs for NO oxidation to NO2 was higher than that of a composite loaded with 10 wt% silicalite under dry conditions. However, the latter had a much better resistance to vapor and exhibited a more stable catalytic activity than the ACFs under moist conditions.