Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
Inhibition Effect of Phosphorus Poisoning on the Dynamics and Redox of Cu Active Sites in a Cu-SSZ-13 NH3-SCR Catalyst for NOx Reduction Environmental Science & Technology (IF9.028), Pub Date : 2021-09-12, DOI: 10.1021/acs.est.1c03630 Anqi Guo, Kunpeng Xie, Huarong Lei, Valentina Rizzotto, Limin Chen, Mingli Fu, Peirong Chen, Yue Peng, Daiqi Ye, Ulrich Simon
Phosphorus (P) stemming from biodiesel and/or lubricant oil additives is unavoidable in real diesel exhausts and deactivates gradually the Cu-SSZ-13 zeolite catalyst for ammonia-assisted selective catalytic NOx reduction (NH3-SCR). Here, the deactivation mechanism of Cu-SSZ-13 by P-poisoning was investigated by ex situ examination of the structural changes and by in situ probing the dynamics and redox of Cu active sites via a combination of impedance spectroscopy, diffuse reflection infrared Fourier transform spectroscopy, and ultraviolet–visible spectroscopy. We unveiled that strong interactions between Cu and P led to not only a loss of Cu active sites for catalytic turnovers but also a restricted dynamic motion of Cu species during low-temperature NH3-SCR catalysis. Furthermore, the CuII ↔ CuI redox cycling of Cu sites, especially the CuI → CuII reoxidation half-cycle, was significantly inhibited, which can be attributed to the restricted Cu motion by P-poisoning disabling the formation of key dimeric Cu intermediates. As a result, the NH3-SCR activity at low temperatures (200 °C and below) decreased slightly for the mildly poisoned Cu-SSZ-13 and considerably for the severely poisoned Cu-SSZ-13.