A systematic evaluation of the catalytic behavior of transition metal (Fe and Mn)–doped ceria-zirconia-alumina oxides on automobile exhaust

In India, air pollution due to the transit sector was a complex challenge which requires an effective holistic approach. Nanostructured CeO₂-ZrO₂/Al₂O₃ samples doped with transition metals (Fe and Mn) are synthesized by a simple co-precipitation method adopting calcination at 500 °C for 5 h. XRD, Raman, and HRTEM investigations unveiled the microstructural properties. The phase stability upon increasing the dopant content was witnessed, favoring the catalytic activity of the samples. The BET surface area of the Mn-doped CeO₂-ZrO₂/Al₂O₃ sample is 134.7 m² g⁻¹, which enhances the surface active oxygen species formation. The XPS compositional analysis ensures the co-existence of Ce⁴⁺/Ce³⁺, Fe³⁺/Fe²⁺, and Mn³⁺/Mn²⁺ redox couples, which generates the surface oxygen vacancies and activates the lattice oxygen migration favors the Mars–van Krevelen mechanism for diesel exhaust treatment. The undoped and Mn-doped CeO₂-ZrO₂/Al₂O₃ samples were coated on perforated stainless steel substrates, and their catalytic performances were examined in the Field Marshal diesel engine using AVL Digas analyzer. The Mn-doped sample reveals the eminent catalytic behavior toward the diesel exhaust treatment. At maximum load, the NO_X and smoke were incredibly diminished to almost 80% with appreciable efficiency. In the future, the prepared catalyst substrates with finely tuned catalysts were analyzed for other fueled vehicles.