Modulated synthesis of MnO₂-decorated Fe–Mn composite oxides：synergistic effects on boosting the performance of toluene oxidation

MnO₂-decorated iron-manganese composite oxides were prepared via a novel method combining hydrolysis driving redox reaction and hydrothermal approach. The differences in physicochemical properties and microstructures were controlled by modulating the ratio of MnO₂ to 5Mn1Fe (The molar ratio of Mn to Fe was 5:1). Characterization results displayed that the excellent efficiency of toluene removal over 3MnO₂/5Mn1Fe catalyst was attributable to the special structure, strong low-temperature reducibility, high surface Mn³⁺/Mn⁴⁺ and O_ads/O_latt molar ratios. The interaction between MnO₂ and 5Mn1Fe played a predominant role in outstanding catalytic efficiency of the hetero-nanostructures. Among all as-prepared catalysts, the highest activity was achieved over the bayberry-like 3MnO₂/5Mn1Fe catalyst with corresponding T₉₀ of 233 °C, much lower than MnO₂ for 313 °C and 5Mn1Fe for 280 °C. This successful strategy could not only be applied to VOCs catalytic oxidation but also provide a novel synthetic path for other catalysis systems.