One-pot synthesis of FeCu–SSZ-13 using Cu–TEPA as the template by adding iron complexes

Abstract

When Cu–TEPA (Cu²⁺ coordinated with tetraethylenepentamine) is used as a template in the one-pot synthesis of Cu–SSZ-13, Cu²⁺ will be reduced to Cu⁰, resulting in a too high Cu content in the product. Herein, by adding iron complexes to the precursor, the reduction of Cu²⁺ could be inhibited and FeCu–SSZ-13 samples with rational Cu and Fe contents were prepared by a simple one-pot strategy. Although these samples show high activity in the NH₃-SCR at low temperature, their high temperature performance is poor due to the lack of strong NH₃ adsorption sites such as Brønsted acid sites. Meanwhile, different iron complexes were used as iron sources to synthesize FeCu–SSZ-13, and among them the sample with sodium nitroprusside shows the highest activity. Due to the large ionic radius of K⁺, it is easily retained which blocks the pores, so the performance of the samples synthesized with a K-type iron source is poorer than that of their Na-type counterparts. Moreover, the activity of the catalyst synthesized with an Fe³⁺ source is higher than that synthesized with an Fe²⁺ source because the valence state of Fe sources has a great influence on the Fe chemical state in the catalysts.