Zhu Mingyun, Wen Yifeng, Shi Lei, Tan Zhiyuan, Shen Yuting, Yin Kuibo, Sun Litao
SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, 210096, China.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
Nanoscale. 2022 Aug 25;14(33):11963-11971. doi: 10.1039/d2nr03101a.
Mn-modified CeO nanomaterials have attracted extensive attention as efficient and promising catalysts for soot combustion due to their low cost and high catalytic activity. However, a detailed mechanism of how Mn promotes soot oxidation over CeO is still not clearly elucidated, which is crucial to further optimize the catalyst for achieving its practical applications. We here report a Mn-doped CeO catalyst with tunable surface Mn chemical valence states to study the Mn-promoting mechanism for improving CeO catalyst activity in soot oxidation. Experimental results show that Mn-doped CeO nanorods with surface Mn chemical valence states being optimized (MnCeO) can lower the eliminating temperature of soot to 410 °C () when in a loose contact and exhibit a strong resistance towards water molecules. The catalytic performances of MnCeO nanorods are comparable with those of other reported oxide catalysts both in the mimetic realistic and ideal reaction environments. Detailed characterization and theoretical calculation results demonstrate that balanced multiple Mn valences can dramatically enhance the catalysts' redox properties and their ability to activate O molecules, as well as improve the dynamic contact efficiency during the oxidation, which synergistically result in superior catalytic performances. This work might provide insight for the future design and preparation of catalysts to efficiently eliminate soot particles.
锰改性的CeO纳米材料因其低成本和高催化活性，作为用于烟灰燃烧的高效且有前景的催化剂而受到广泛关注。然而，关于锰如何促进CeO上烟灰氧化的详细机制仍未明确阐明，这对于进一步优化催化剂以实现其实际应用至关重要。我们在此报告一种具有可调表面锰化学价态的锰掺杂CeO催化剂，以研究锰促进CeO催化剂在烟灰氧化中活性的机制。实验结果表明，表面锰化学价态得到优化的锰掺杂CeO纳米棒（MnCeO）在松散接触时可将烟灰的消除温度降低至410℃（），并且对水分子表现出很强的抗性。在模拟实际和理想反应环境中，MnCeO纳米棒的催化性能与其他报道的氧化物催化剂相当。详细的表征和理论计算结果表明，平衡的多种锰价态可显著增强催化剂的氧化还原性能及其激活O分子的能力，以及提高氧化过程中的动态接触效率，这些协同作用导致优异的催化性能。这项工作可能为未来高效消除烟灰颗粒的催化剂的设计和制备提供思路。
