Electronic properties and catalytic performance for DME combustion of lanthanum manganites with partial B-site substitution

• Isostructural LaMn0.5B0.5O3 (B = Cr, Fe, Co, or Ni) exhibits a linear correlation between reaction rate and Mn4+ content.
• Substitution with Co and Ni enhances the redox properties and increases the catalytic activity of LaMnO3.
• Substitution with Cr and Fe diminishes the redox properties and decreases the catalytic activity of LaMnO3.

The effect on the geometric, electronic, and catalytic properties of LaMnO3 oxides of replacement of 50% Mn with Cr, Fe, Co, and Ni in combustion reactions of dimethyl ether has been studied. The similarity in the ionic radius does not produce larger differences in the geometric properties of the compounds, whereas the differences in the stability of their cation valences produce significant changes in their electronic properties. The high stability of Cr3+ and Fe3+ species does not increase the Mn4+/Mn3+ redox pair ratio in LaMn0.5Cr0.5O3 and LaMn0.5Fe0.5O3. Meanwhile, the high stability of Co2+ and Ni2+ species favors the oxidation of Mn3+ to Mn4+ and the mobility of anionic oxygen in the LaMn0.5Co0.5O3 and LaMn0.5Ni0.5O3 catalysts, which improves their catalytic performance.

Figure optionsDownload high-quality image (122 K)Download as PowerPoint slide