Simultaneous NO(x) and Particulate Matter Removal from Diesel Exhaust by Hierarchical Fe-Doped Ce–Zr Oxide

[Image: see text] Particulate matter and NO(x) emissions from diesel exhaust remains one of the most pressing environmental problems. We explore the use of hierarchically ordered mixed Fe–Ce–Zr oxides for the simultaneous capture and oxidation of soot and reduction of NO(x) by ammonia in a single step. The optimized material can effectively trap the model soot particles in its open macroporous structure and oxidize the soot below 400 °C while completely removing NO in the 285–420 °C range. Surface characterization and DFT calculations emphasize the defective nature of Fe-doped ceria. The isolated Fe ions and associated oxygen vacancies catalyze facile NO reduction to N(2). A mechanism for the reduction of NO with NH(3) on Fe-doped ceria is proposed involving adsorbed O(2). Such adsorbed O(2) species will also contribute to the oxidation of soot.