Hydrocarbon Reformer Trap by Use of Transition Metal Oxide-Incorporated Beta Zeolites

Abstract

The concept of a hydrocarbon reformer trap is proposed as a novel technology for cleaning up automobile emissions. Zeolite beta with/without metal species such as iron, manganese, or cobalt is synthesized through a solid phase transformation of mesoporous (metallo)aluminosilicate MCM-41 along with tetraethylammonium cations for structure direction to zeolite beta. The microporosity of zeolite functions as a hydrocarbon trap, and the metal species inside the pores provide a reforming site.

“Super Hydrocarbon Reformer Trap” for the Complete Oxidation of Toluene Using Iron‐Exchanged β‐Zeolite with a Low Silicon/Aluminum Ratio

“…Thus, it was suggested that Fe‐loaded zeolites can catalyze toluene oxidation. The concept of the proposed HC reformer trap is confirmed here in further detail. Fe‐containing zeolites are known to be effective catalysts for various reactions, such as the selective catalytic reduction of nitrogen oxides with hydrocarbons or ammonia, the hydroxylation of benzene or methane with N 2 O, and the direct decomposition of N 2 O .…”

“…Toluene‐TPD was used to evaluate the zeolites as a HC trap . A mixture of 20 mg of zeolite with 100 mg of silicon carbide was placed in a 5 mm inner‐diameter glass tube and pretreated at 390 °C for 1 h in a He stream with or without O 2 .…”

“…At elevated temperatures of the entire system, the adsorbed HCs are desorbed and oxidized by the thermally activated TWC. Zeolites are used frequently as the material for the HC trap because of their strong affinity to HCs and high thermal stability …”

“…Our group has proposed the concept of an improved HC trap called the “HC reformer trap”, in which transition metal species such as Fe, Mn, and Co are incorporated into the zeolites . In this concept, these trap materials not only hold HCs at a low temperature but also oxidize them catalytically into more reactive substances.…”

Synthesis and Catalytic Performance of the Framework-Substituted Manganese β Zeolite

“…However, very few papers have reported it so far. Ogura et al [18] prepared Mn-loaded Al-b zeolite through the solid phase transformation of Mn-containing mesoporous silica MCM-41, and used it as an effective hydrocarbon reformer trap for cleaning up automobile emissions, but they did not characterize the state of manganese in zeolite structure. In this study, the incorporation of manganese into the framework of b zeolite is achieved by a direct hydrothermal synthesis without adding any assistant agents, which is evidenced by XRD, UV-vis, and inductively coupling plasma (ICP).…”