A series of Co-based oxides were synthesized and investigated as passive NOx adsorbers (PNAs). The morphology variation of Co3O4 oxide from nanoparticle to flake shape enhanced the NOx storage efficiency (NSE) and improved the NOx desorption capability. The enhanced NSE of the flake-like sample is related to its abundant surface oxygen species and large surface area. DRIFTS and CO2-TPD experimental results indicated that Co3O4-flake and Co7Ni3Ox-flake samples with moderate basicity could store NOx as nitrite species, which facilitated NOx desorption at lower temperatures.
All Science Journal Classification (ASJC) codes
- Process Chemistry and Technology