SO2-resistant NOx reduction over Cu-SAPO-34 catalysts via creating sulfur-phobic Cu sites

Commercial Cu-SAPO-34 catalysts suffer from poisoning of SO2 in the selective catalytic reduction of NOx with NH3 (NH3-SCR). It is challenging to inhibit the deposition of ammonium hydrogen sulfate (ABS) and the sulfation of Cu species in the presence of SO2. Here, we originally demonstrate that sulfur-philic ZCuOH sites could be converted into sulfur-phobic Z(2)Cu sites in Cu-SAPO-34 by a hydrothermal aging (HA) method, thereby improving the SO2 resistance. After the HA treatment, the SO2 adsorption capacity and ABS deposition over catalysts are both reduced by 30-40% compared to that over the original counterpart. Moreover, SO2-induced overoxidation and polymerization of Cu species are also suppressed, thus maintaining the redox balance of the NH3-SCR reaction. This work provides an effective approach to enhance the SO2 resistance of Cu-SAPO-34 catalysts via creating sulfur-phobic Z(2)Cu sites, which is of significance for practical applications.

Automated summary

The hydrothermal aging method converts sulfur-philic ZCuOH sites into sulfur-phobic Z(2)Cu sites in Cu-SAPO-34 catalyst, improving its resistance to SO2. This reduces the adsorption capacity and deposition of ammonium hydrogen sulfate (ABS) and suppresses the overoxidation and polymerization of Cu species, maintaining the redox balance of the NH3-SCR reaction.