Application of heterobimetallic zeolite in NH ₃ SCR of NO _x and propane aromatization

The catalytic properties and durability of zeolites are usually tuned by replacing the aluminum in the framework with other elements such as B, Ga, In, etc, from hydrothermal synthesis. A direct solution exchange method has been discovered to partially substitute aluminum in metal exchanged zeolites, yielding heterobimetallic materials with significantly enhanced catalytic properties. For example, CuFe-ZSM-5, synthesized from the solution exchange of Cu-ZSM-5 and Fe(NO ₃) ₃, shows over 80% NO _x reduction under fast NH ₃-SCR conditions at 150°C while Cu-ZSM-5 demonstrates its maxima capability at 30%. Indium exchanged zeolite, CuIn-ZSM-5, shows significantly higher propane conversion (23.5%) than In-ZSM-5 (5.4%) at 450°C, also with better benzene selectivity. Other zeolites, e.g., zeolite beta, are also investigated with the direct solution exchange method to produce the heterobimetallic catalysts. We will also present our results on computational modeling of the possible configurations of the heterobimetallic core in the zeolite structure.