Metal–organic frameworks derived Ag/Co3O4–MnO2 for the catalytic oxidation of formaldehyde

Co3O4–MnO2 mixed oxides with different Co/Mn molar ratios (9:1 and 7:3) were prepared by thermal decomposition of Co–Mn–MOFs. Then a loading of 0.96 wt% Ag was introduced into the Co3O4–MnO2 support via the conventional impregnation method. The as-synthesized catalysts were evaluated for the oxidation of formaldehyde (HCHO). It has been found that Ag/Co3O4–MnO2 (9:1) performed remarkable catalytic activity for the HCHO oxidation, which could achieve 100% HCHO conversion at 80 °C and retain for 39 h. With the addition of 5% H2O, a slight drop of HCHO conversion (3%) was discovered. Nevertheless, the catalytic activity of Ag/Co3O4–MnO2 (9:1) rapidly recovered as taking H2O away. According to the physical and chemical characterization analysis, the strong interaction among Ag, Co3O4 and MnO2 could improve the reducibility and increase the amount of surface active oxygen species, which played vital roles in the oxidation of HCHO. This study provides a strategy for developing cost-effective and high-efficient catalysts to remove HCHO.