Doped barium cerate perovskite catalysts for simultaneous NOx storage and soot oxidation

[Display omitted] •Catalysts were prepared by a two step process involving solid state synthesis and high energy milling.•Catalysts were able to simultaneously store NOx and oxidize soot.•The barium cerate sample co-doped with Zr and Co exhibited the highest catalytic performance. A series of doped barium cerate perovskite catalysts (BaCeO3-δ, BaCe0.8Zr0.2O3-δ and BaCe0.8Zr0.1Co0.1O3-δ) were prepared by a two-step process consisting of solid-state synthesis followed by high-energy ball milling. X-ray diffraction studies showed that the dopants (Zr and Co) were incorporated into the perovskite lattice. TPR studies revealed that the high-energy ball milling process significantly enhanced the reducibility of the catalysts. XPS data indicated a shift in electron density away from the metal centres and an increase in defect oxides, for the high-energy ball milled catalysts, which led to enhanced activity of the catalysts. The catalytic performance was evaluated in a fixed bed reactor system under simulated diesel exhaust conditions, including water. The high-energy ball milled barium cerate sample co-doped with Zr and Co exhibited NOx storage of ∼228 μmol/g at 380 °C and a Tmax, at which the rate of soot oxidation reaction was maximum, of 436 °C.