Crossed nanosheets of transition metal oxide (TMO-NS: Co-NS, Mn-NS and Fe-NS) were synthesized by a facile hydrothermal method and employed for soot combustion in the NO/O-2/N-2 and O-2/N-2 atmosphere under gravitational contact mode (GCM). They show high catalytic activities for soot combustion due to the macroporous structure of the as-prepare catalysts increasing the soot-catalyst contact efficiency. The XRD and XPS results reveal that the active phases in the corresponding catalysts exist as Co3O4, Mn2O3 and Fe2O3, respectively. Among these catalysts, the Co-NS shows the best activity for soot combustion, especially in the presence of NO, whose catalytic activity of T-50 (391 degrees C) and S-CO2 (100%) is as good as that of the Pt/Al2O3 catalyst. The excellent performance of the Co-NS catalyst results from several factors: the highest intrinsic activity (TOF = 1.77 x 10(-5) s(-1)); the highest redox property as revealed by H-2-TPR and soot-TPR; the largest amount of active oxygen species as clarified by XPS; the highest ability of NO oxidation to NO2 supported by NO-TPO. In addition, the multiporous structure of Co3O4 nanosheets is facilitated for the mass transfer. In the O-2 atmosphere, soot particulates are directly oxidized by the surface adsorbed oxygen. After introducing of NO, the soot particulates are readily oxidized by NO2 at the low temperature (< 330 degrees C); with the increase of the reaction temperature (330-450 degrees C), both the active oxygen species and NO2 involve in soot combustion. (C) 2017 Elsevier B.V. All rights reserved.