Holey Co-Ce oxide nanosheets as a highly efficient catalyst for diesel soot combustion

Cobalt-based catalysts were synthesized through the evolution of Co3O4 nanoparticles into holey nanosheets. The holey Co-Ce oxide nanosheets were found to have the highest activity and stability for soot combustion at loose contact mode as a result of the successful doping of trace amount of Ce ions in Co3O4, which improves the intrinsic activity. Additionally, better solid-solid contact was also achieved on holey Co-Ce oxide nanosheets because of the mesoporous structure and large external surface formed. The catalytic mechanism was investigated with in-situ Raman spectra, which indicated that the superoxide species and O-2(delta-) (0 < delta < 1) species had reacted with soot preferentially, and the weakly bonded oxygen species had a low temperature activity even in the absence of O-2. Overall, this study indicated that the two-dimensional (2D) holey Co-Ce nanosheets exhibited superior catalytic performance for soot combustion, which is of great significance for future applications.