The synthesis of Cu/SAPO-34 catalysts and evaluation ability of NOx treatment by NH3-SCR with Cu/ZSM-5 catalyst using commercial ZSM-5 as support

Abstract

SAPO-34 molecular sieves were synthesized under hydrothermal conditions using different combinations of tetraethyl ammonium hydroxide (TEAOH), morpholine (Mor), and triethylamine (TEA) as organic structure-directing agents and economical silicon source by colloidal silica LUDOX AS-30. The products were characterized by X-ray diffraction, Field Emission Scanning Electron Microscopes, Energy-dispersive X-ray spectroscopy, NH₃ temperature - programmed desorption, N₂ adsorption-desorption. Electron paramagnetic resonance technique was applied to identify isolated Cu²⁺ ions in the framework. Although materials with the same chabazite framework structure are obtained, they possess different physicochemical properties, especially crystal size and acidity. Catalytic performances of Cu/SAPO-34 and Cu/ZSM-5 using commercial ZSM-5 as support with the loading of 3 wt% prepared by liquid ion-exchange method was performed for selective catalytic reduction (SCR) of NO_x with NH₃.