The synergistic performance of redox couples enhanced with phase inter-grown ceria-zirconia-alumina mixed oxides: A robust three-way catalyst for diesel exhaust abatement

The CeO 2 -ZrO 2 and Al 2 O 3 (75 wt% and 25 wt%) were prepared by co-precipitation route, calcined at 500 °C for 5 h and mechanically mixed. Three compositions of Ce/Zr (20:80, 50:50, and 80:20) were synthesized and their microstructural properties was observed via X-ray diffraction (XRD), and Raman analysis. The CeO 2 -ZrO 2 /Al 2 O 3 (Ce/Zr-50:50) sample reveals the mixed phase formation of cubic and tetragonal, which facilitates the catalytic activity via oxygen ion diffusion from O 2- sub-lattice to the sample surface. The CeO 2 -ZrO 2 /Al 2 O 3 (Ce/Zr-50:50) was further investigated using High-resolution transmission electron microscope (HRTEM), Brunauer-Emmett-Teller (BET) study, X-ray photoelectron spectroscopy (XPS), and Scanning electron microscope (SEM). The surface area of CeO 2 -ZrO 2 /Al 2 O 3 (Ce/Zr −50:50) was 91.2 m 2 g −1 , which provides surface active oxygen species to participate in diesel exhaust treatment via redox reactions. The XPS spectra of CeO 2 -ZrO 2 /Al 2 O 3 (Ce/Zr −50:50) sample confirms the Ce 3+ reduction along with the formation of oxygen vacancies. To perform catalytic reaction, the CeO 2 -ZrO 2 /Al 2 O 3 (Ce/Zr −50:50) sample was coated on the perforated stainless-steel substrates by a unique and cost-effective technique, which could be economically advantageous to produce the catalyst for commercial uses on a large scale. The sample was tested at different load conditions. At maximum load condition, the sample exhibited substantial reduction in CO, HC, CO 2 , NO x , and smoke. • Noble-metal free CeO 2 -ZrO 2 /Al 2 O 3 with Ce/Zr = 1 sample shows mixed phases. • This sample possess reduced particle size of 15 nm and high surface area of 91.2 m 2 g −1 . • The synergistic Ce 3+ -O v - Zr 4+ sites boost the oxygen transport and redox activity. • Under lean-burn conditions, the NOx emissions are significantly reduced.