While diesel engines are extensively employed, soot from diesel engines lead to serious air pollution, which should be eliminated through catalytic soot oxidation processes. As Co₃O₄ represents a practical catalyst for oxidizing soot, it is critical to further investigate relationships of morphology-property-reactivity of Co₃O₄ catalysts for optimizing design of Co₃O₄ for soot oxidation. Thus, the present study, as the first attempt, aims to manipulate morphologies of Co₃O₄ microspheres to exhibit different surficial hierarchical nanostructures for comparing their corresponding catalytic activities. Specifically, four hierarchical Co₃O₄ microspheres (HCOMs) are fabricated, including Co₃O₄ with flower morphology (COF), Co₃O₄ with urchin morphology (COU), Co₃O₄ with sheet morphology (COS), and Co₃O₄ with pyramid morphology (COP), for comparisons in catalytic soot oxidation. The results indicate that these HCOMs showed much higher catalytic activities than the commercial spherical Co₃O₄ nanoparticles and most of reported cobalt-based catalysts as these HCOMs possessed high surface areas and porous nanostructures. In particular, among these HCOMs, COP stood out as the most advantageous HCOM for soot oxidation as COP contained more reactive surface and more superior redox properties than other HCOMs, thereby enabling COP to accelerate soot oxidation. These HCOMs could be also recyclable for soot oxidation over multiple cycles without loss of catalytic activities. These results and findings demonstrate that HCOMs are certainly promising cobaltic catalysts for oxidizing soot, and, through this present study, the relationship between morphologies, properties and catalytic activities can be correlated to provide important insights to design and apply hierarchically nanostructured Co₃O₄ catalysts for soot oxidation.

尽管柴油发动机被广泛使用，但柴油发动机产生的烟尘会导致严重的空气污染，应通过催化性烟尘氧化工艺消除这种污染。由于Co ₃ O ₄代表一种用于氧化烟灰的实用催化剂，因此至关重要的是，进一步研究Co ₃ O ₄催化剂的形态-性能-反应性之间的关系，以优化烟灰氧化的Co ₃ O _4的设计。因此，作为首次尝试，本研究旨在操纵Co ₃ O _4的形态。微球表现出不同的表面分层纳米结构，以比较它们相应的催化活性。具体而言，四分层钴₃ ö _4个微球（东道国管理措施）被制造，含有Co ₃ ö ₄与花形态（COF），CO ₃ ö ₄与海胆形态（COU），CO ₃ ö ₄与片材的形态（COS），和具有金字塔形态（COP）的Co ₃ O ₄，用于催化烟灰氧化。结果表明，这些HCOM的催化活性远高于商业球形Co ₃ O _4。纳米颗粒和大多数报道的钴基催化剂，因为这些HCOM具有高表面积和多孔纳米结构。特别地，在这些HCOM中，COP比其他HCOM具有更高的反应性表面和更优异的氧化还原特性，从而成为烟灰氧化最有利的HCOM，从而使COP能够促进烟灰氧化。这些HCOMs还可以在多个循环中循环使用以进行烟灰氧化而不会损失催化活性。这些结果和发现表明，HCOMs无疑是用于氧化烟灰的钴催化剂，通过本研究，可以关联形态，性质和催化活性之间的关系，从而为设计和应用纳米级结构的Co ₃ O提供重要的见解。_4种烟灰氧化催化剂。