Phosphorylated MCM-22 supported CeO2-ZrO2 nanosphere catalyst with strong anti-PbCl2 ability for NH3-SCR

The flue gases emitted from boilers such as waste incineration plants and thermal power plants often contain a certain amount of Pb. This Pb can cause the NH3-SCR catalyst to deactivate, thereby increasing NO_x emissions. To address this issue, phosphorylated MCM-22 was used as the support for CeO₂-ZrO₂ nanospheres to synthesize CZMP catalysts with strong Pb poisoning resistance. These catalysts were able to purify more than 80% of NO_x at a temperature of 300 °C after Pb poisoning. X-ray diffraction, powder FT-IR, and TEM analyses revealed that the structure and composition of the catalyst is stable and unchanged before and after Pb poisoning. NH₃-TPD result showed that phosphoric acid modification could change the acidity of the catalyst and H₂-TPR indicated the increase of low temperature redox sites, enhancing its anti-poisoning ability at low temperatures. In-situ DRIFT studies indicated that phosphoric acid modification caused rapid decomposition of nitrate intermediates on the catalysts, with the reaction dominated by an E-R mechanism