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

[Display omitted] •Mn-Fe oxides are in-situ prepared using K2FeO4 and MnSO4.•Mn3O4-Fe2O3-Ni performs the best catalytic ability of toluene oxidation.•Mn3O4-Fe2O3-Ni exhibits better physical–chemical properties. 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 (103) and (112) 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 (112) plane in Mn3O4-Fe2O3-Ni than that of (103) 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.