Quasi-operando quantification of Cu(ii) ions in Cu-SSZ-13 catalyst by an NH3 temperature-programmed reduction method†
Abstract
A quasi-operando NH3 temperature-programmed reduction method (NH3-TPR), with N2:Cu = 1:1, is developed to quantify total Cu(II) ions in Cu-SSZ-13 quenched from SCR-relevant reactions, and its accuracy is confirmed by in situ EPR. [Cu(OH)]+-Z and Cu2+-2Z can be further distinguished by NH3 reduction temperatures, and their different reducibility in SCR is revealed.