Constructing bifunctional Co/CeO2 micro-structured catalysts for soot elimination

Abstract

Catalytic oxidation is considered to be an efficient technology for eliminating the soot particulates emitted from diesel engines. Nevertheless, the inadequate contact between the catalyst and soot particulates, as well as the low oxidation capability of the catalysts, severely limit the further development of this technique. In this study, the bifunctional Co/CeO₂ catalysts with flower-like structure were deliberately designed and prepared. The optimal catalyst (20 % Co/CeO₂) demonstrated exceptional catalytic performance, with T₅₀ as low as 364 °C. Furthermore, a series of characterizations were performed to investigate the catalyst structure-activity relationship. The results indicated that the Co/CeO₂ demonstrated two obvious functions in the improvement of soot catalytic elimination. One was that three-dimensional flower-like morphology enhanced the contact efficiency between the catalysts and soot particulates. The other one was the synergistic interactions between CeO₂ and Co₃O₄ gave rise to the abundant active surface adsorbed oxygen species, significantly improving the catalytic oxidation activity for soot elimination. This work offered a new avenue to design and construct efficient catalysts for diesel soot combustion.