Mn3O4 doped with highly dispersed Zr species: a new non-noble metal oxide with enhanced activity for three-way catalysis

In this article, zirconium-doped manganese oxides have been synthesized through a one-step solvothermal method and used in three-way catalysis. Zr4+ was introduced into the lattice of Mn3O4 and was shown to be highly dispersed in the Mn3O4 matrix, as confirmed by XPS, Raman spectroscopy and EDS-Mapping. Appropriate Zr4+ doping resulted in lattice distortion, leading to the exposure of more oxygen vacancies and a better oxygen storage capacity (OSC: 658.8 mu mol g(-1)) than pure Mn3O4 (163.2 mu mol g(-1)). As non-noble metal three-way catalysts (TWCs) for a CO + NO + C2H6 model reaction, the catalytic activities of the as-synthesized samples were evaluated. Notably, the catalytic tests showed that the activities of the zirconium-doped samples are higher than that of pure Mn3O4. Furthermore, the ZM-2 sample (with a 20% Zr/Mn molar ratio) shows the best complete conversion of CO at 228 degrees C, NO at 334 degrees C and C2H6 at 400 degrees C (nearly 100 degrees C lower than those of pure Mn3O4) and excellent anti-high temperature performance. Our work will reduce the use of precious metals and provide a feasible route to prepare economical catalysts for exhaust emission control.