Storage of NO2 on potassium oxide co-loaded with barium oxide for NOx storage and reduction (NSR) catalysts

Barium oxide-based NO x storage and reduction (NSR) catalysts with different amounts of potassium oxide were prepared to investigate the role of potassium oxide in the aspects of amount and strength of NO 2 storage. The dispersion of barium and potassium oxides on alumina, the amount and state of NO 2 stored on them, and the desorption profiles of NO 2 from them were examined by XRD, N 2 adsorption, electrical conductivity measurement, XPS, FT-IR and TPD techniques. Barium and potassium oxides were mainly loaded in the mesopores of the alumina and the NO 2 was stored by being converted to nitrates. The alumina itself had a small capacity for NO 2 storage, but the impregnation with potassium oxide increased the capacity. The co-loading of potassium oxide and barium oxide enhances the strength of the interaction between the storage material and NO 2 , shifting the desorption peak of NO 2 to a elevated temperature.