Migration of Cu Ions in SAPO-34 and Its Impact on Selective Catalytic Reduction of NO<i>_x</i>with NH₃

Migration of copper species from the surface region upon activation of Cu–SAPO-34 leads to a several-fold increase in catalytic activity for the selective catalytic reduction of NOx with NH3. The temperatures required for the activation are higher than normal calcination temperatures and lead to a homogeneous transition metal distribution that renders Cu–SAPO-34 an industrially promising candidate for NOx removal.