In situ sulphur poisoning and regeneration of Cu-CHA deNOx catalysts

Excellent performance of Cu-exchanged chabazite zeolites (Cu-CHA) as catalysts for NOx removal from exhaust fumes has very recently paved the way for these materials to the catalytic converters of the last-generation diesel cars. However, catalytic activity of these materials decreases after prolonged exposure to sulphur, ever-present in the diesel fuel. To understand the mechanism of deactivation we need to investigate Cu-S species which are formed after interaction with SO2. This proposal aims to reveal the mechanisms of sulphur poisoning and regeneration of Cu-CHA zeolites at the molecular level, monitoring the electronic structure and local environment of sulphur by element-selective X-ray absorption spectroscopy during the in situ adsorption and desorption of sulphur. Obtained results will be crucial to optimise regeneration procedures for the catalysts, increasing thus their efficiency.