Advanced synchrotron techniques for operando characterisation of Cu-CHA deNOx catalyst
The current contribution summarizes our three-year work on Cu-CHA zeolite, which is a very promising material for the selective catalytic reduction of harmful NOx gases from industrial and car exhausts. We have performed several X-ray absorption and X-ray emission experiments at ESRF synchrotron (Grenoble, France) to collect an extensive set of data, allowing to characterize the material in many reaction-relevant states. Particularly, due to the combination of experimental and theoretical work we were able to shed light on the local environment and electronic structure of Cu ions hosted in the cavities of the zeolitic framework after the activation of the material in both inert and oxidative atmospheres, upon interaction with gases of SCR mixture and in operando SCR conditions. This allowed us to develop a consistent mechanism of the SCR reaction and to prove its main stages.