The Catalytic Oxidation of Formaldehyde by FeOx-MnO2-CeO2 Catalyst: Effect of Iron Modification

A series of FeOx-MnO2-CeO2 catalysts were synthesized by the surfactant-templated coprecipitation method and applied for HCHO removal. The influence of Fe/Mn/Ce molar ratio on the catalytic performance was investigated, and the FeOx-MnO2-CeO2 catalyst exhibited excellent catalytic activity, with complete HCHO conversion at low temperatures (40 °C) when the molar ratio of Fe/Mn/Ce was 2/5/5. The catalysts were characterized by N2 adsorption and desorption, XRD, H2-TPR, O2-TPD and XPS techniques to illustrate their structure–activity relationships. The result revealed that the introduction of FeOx into MnO2-CeO2 formed a strong interaction between FeOx-MnO2-CeO2, which facilitated the improved dispersion of MnO2-CeO2, subsequently increasing the surface area and aiding pore development. This promotion effect of Fe enhanced the reducibility and produced abundant surface-active oxygen. In addition, a great number of Oα is beneficial to the intermediate decomposition, whereas the existence of Ce3+ favors the formation of oxygen vacancies on the surface of the catalyst, all of which contributed to HCHO oxidation at low temperatures.