A series of highly efficient MnOx-Co3O4-CeO2 mixed oxides, synthesized by a sol-gel citric acid method, were applied to eliminate indoor formaldehyde (HCHO). The influence of the molar ratio of Mn/Co/Ce was investigated. The catalyst could efficiently eliminate HCHO into CO2 and H2O when the molar ratio of Mn/Co/Ce was 16/19/1. Complete HCHO conversion was achieved at a temperature as low as 100 degrees C. The prepared samples were characterized by N-2 adsorption and desorption, XRD, H-2-TPR and O-2-TPD techniques to explain the improvement of catalytic activity. The results show that the introduction of MnOx, into Co3O4-CeO2 could improve the high dispersion of Co3O4 and then increase the surface areas. Especially, the addition of MnO enhanced reducibility and abundant surface active oxygen of MnOx-Co3O4-CeO2, which contributed to the excellent catalytic activity toward complete elimination of HCHO. (C) 2016 Elsevier B.V. All rights reserved.