The role of Si coordination structures in the catalytic properties and durability of Cu-SAPO-34 as NH3-SCR catalyst for NOx reduction

Si coordination structures have been proven to greatly influence the ammonia-selective catalytic reduction (NH3-SCR) catalytic properties and the hydrothermal stability of Cu-based silicoaluminophosphateform catalysts. However, the role of various Si coordination structures in the NH3-SCR reaction over CuSAPO-34 catalyst remains unknown. Herein, a batch of Cu-SAPO-34 samples with various Si contents was synthesized via a one-pot method to study the role of Si coordination structures in the NH3-SCR catalytic properties and hydrothermal stability. Cu/34-2 with the highest proportion of Si(xOAl) (x = 1 similar to 3) structures exhibits remarkable durability with 90% NO reduction efficiency within 200 similar to 450 degrees C even after a hydrothermal aging treatment at 850 degrees C. In contrast, Cu/34-1 and Cu/34-4 with the highest proportions of Si(4OAl) and Si(0OAl) structures, respectively, are significantly deactivated by the same hydrothermal treatment. To better understand this phenomenon, the relationship between the Si coordination structures and SCR performance is established using characterization techniques and kinetics measurements. Results reveal that a high content of Si(4OAl) and Si(0OAl) is detrimental to the hydrothermal stability of Cu-SAPO-34 catalyst. However, Si(xOAl) (x = 1 similar to 3) structures are conducive to the stabilization of isolated Cu2+, thus enhancing the stability to severe hydrothermal treatment. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Si coordination structures have a significant influence on the catalytic properties and hydrothermal stability of CuSAPO-34 catalyst in NH3-SCR reaction. Cu/34-2 with Si(xOAl) (x = 1 to 3) structures exhibits remarkable durability and high NO reduction efficiency, while Cu/34-1 and Cu/34-4 with Si(4OAl) and Si(0OAl) structures, respectively, are significantly deactivated after hydrothermal treatment.