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. 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 active Cu centres by element-selective X-ray absorption and X-ray emission spectroscopies (XAS and XES) 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.