Poisoning effect of K with respect to Cu/ZSM-5 used for NO reduction

Cu/ZSM-5 is able to catalyze the reduction of NOx to N-2 (NH3-SCR), but the poisoning effect of K in this regard has been barely studied. Herein, the poisoning effect of K with respect to Cu/ZSM-5 in NH3-SCR was established via catalytic testing, and both Cu/ZSM-5 and K-poisoned Cu/ZSM-5 were probed by using XRD, N-2 sorption, TEM, H-2-TPR, XPS, NH3-TPD, and NO-TPD. In addition to these characterization tools, in-situ DRIFTS was employed to probe the adsorbed species and reaction intermediates, thus giving important information about the possible reaction mechanisms. In all, the presence of K led to decreased exposure of active CuO dispersed on ZSM-5, inhibited the adsorption of NH3 and NOx to some extent, minimized the formation of active bridged nitrate, and facilitated the formation of inactive bidentate nitrate.

Automated summary

The study established the poisoning effect of K on Cu/ZSM-5 in NH3-SCR through various characterization methods, revealing decreased exposure of active CuO, inhibited adsorption of NH3 and NOx, minimized formation of active bridged nitrate, and facilitated formation of inactive bidentate nitrate.