In situ construction of Mn-Fe multi oxides derived from K2FeO4 and MnSO4 for high-efficient degradation of toluene

In this work, a series of manganese-based multi oxide (Mn3O4-Fe2O3) was in-situ synthesized using K2FeO4 and MnSO4 as the precursor via one-step hydrothermal method. Catalytic evaluation shows that Mn3O4-Fe2O3-Ni performs the best activity among the prepared catalysts. T90% and T50% of toluene conversion on Mn3O4-Fe2O3-Ni are 257 and 223 °C, respectively, which are 59 and 28 °C lower than those of Mn3O4-Fe2O3-140. XRD analysis proves that the prepared catalysts are composed of Mn3O4 and Fe2O3; N2-BET indicates that Mn3O4-Fe2O3-Ni has a higher specific surface area; HRTEM analysis implies that the (1 0 3) and (1 1 2) of Mn3O4 (PDF #18–0803) crystal planes are exposed on Mn3O4-Fe2O3-140 and Mn3O4-Fe2O3-Ni, respectively, implying that the introduction of Ni can result in the change of exposed plane. Raman, XPS and O2-TPD analysis implies that there are abundant lattice defects and abundant surface adsorbed oxygen. DFT calculations suggests that the oxygen vacancies are more likely to be formed on the (1 1 2) plane in Mn3O4-Fe2O3-Ni than that of (1 0 3) plane in Mn3O4-Fe2O3-140, which is consistent with the analysis result of Raman spectra and O2-TPD. At last, the possible degradation route of toluene oxidation on Mn3O4-Fe2O3-Ni is induced.