SCR catalyst
A copper-CHA zeolite catalyst for SCR of NO x is disclosed.
1. A one-pot synthesis method for making a catalyst composition comprising a zeolite having a CHA framework, a molar silica-to-alumina ratio (SAR) of 45 to 85, and an atomic copper-to-aluminium ratio of at least 1.25, which method comprising forming a reaction mixture containing a source of silica, a source of alumina, a first CHA framework organic templating agent in the form of a copper metal-amine, a second distinct organic CHA templating agent, and seed crystals; heating the reaction mixture to facilitate crystallization and precipitation of the crystals of the catalyst composition; and collecting, washing and drying the crystals.
2. The method of claim 1 , wherein the copper metal-amine is Cu-tetraethylenepentamine (Cu-TEPA) and the second distinct organic CHA templating agent is N,N,N-dimethylethylcyclohexylammonium (DMECHA).
3. The method of claim 1 , wherein the reaction mixture is free from fluorine.