Operando sulphur poisoning and regeneration of Cu-CHA deNOx catalysts

Emission of nitrogen oxides (NOx) from diesel vehicles is a major contributor to air pollution around the world, especially in densely populated areas. To comply with NOx emission regulations, diesel vehicles are equipped with NH3- SCR catalysts, which is the most effective technology for mitigation of NOx emissions. 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 spectroscopy (XAS) during the in operando adsorption and desorption of sulphur under real SCR conditions. Obtained results will be crucial to optimise regeneration procedures for the catalysts, increasing thus their efficiency.