Deactivation of barium oxide-based NOx storage and reduction catalyst by hydrothermal treatment

The deactivation of a barium oxide-based NO x storage and reduction (NSR) catalyst with hydrothermal treatment was studied by treating it with 10 vol% water vapor diluted in nitrogen at 850°C. XRD, XPS, SEM, IR of CO adsorption, and the N 2 adsorption was used to investigate the physical and chemical changes of the NSR catalyst caused by the hydrothermal treatment. The 12 h hydrothermal treatment decreased its NO 2 storage capacity by 20%. However, the hydrothermal treatment significantly decreased its ability to reduce the stored NO 2 . The formation of an inactive phase consisting of platinum and aluminum is believed to be the cause of the severe deactivation of the NSR catalyst.