K促进的纳米片状水滑石衍生CoAlO金属氧化物催化碳烟燃烧

采用水热法合成了负载K的纳米片状水滑石衍生CoAlO金属氧化物，其表现出优异的催化碳烟燃烧活性.氢气-程序升温还原（H₂-TPR）实验结果表明，K与Co之间的相互作用提高了催化剂的氧化还原性能.X射线光电子能谱（XPS）分析结果表明，K的负载增大了表面Co²⁺/Co³⁺的比例，促进了氧空位的产生，提高了催化剂对气相氧的吸附能力.碳烟-程序升温还原（Soot-TPR）实验结果表明，K的负载增加了表面吸附氧数量.动力学实验结果表明，K的负载增加了单位质量催化剂上的活性氧数量、反应速率和转化频率（TOF），从而提高了催化剂的本征活性.另外，碳烟颗粒可以分散在纳米片的层间，与活性位点的接触效率得到提高，也有利于提高催化碳烟燃烧活性.

K Promoted Nanosheets-like Hydrotalcite-derived CoAlO Metal Oxides for Catalytic Soot Combustion

We synthesize the K supported nanosheets-like hydrotalcite-derived CoAlO metal oxide by a facile hydrothermal method, which exhibits the superior catalytic performance for soot combustion. The H₂-TPR results show that the interaction between K and Co leads to the improved redox ability of 5K/CoAlO. The Co_2p XPS results show that the Co²⁺/Co³⁺ ratios get increased after loading K on the CoAlO support. It demonstrates that the K loading promotes the transition of cobalt species from Co³⁺ to Co²⁺, which leads to the generation of oxygen vacancies. The O_1s XPS results show that the O_ads/(O_ads + O_lat) ratio increases after K loading. The soot-TPR results indicate that the interaction between K and Co contributes to the adsorption of gaseous O₂ remarkably. During kinetic experiments, 5K/CoAlO exhibits the high reaction rate per unit mass of catalyst, active oxygen(O^*) amount per unit mass of catalyst and TOF, which demonstrates that the interaction between K and Co improves the intrinsic activities of 5K/CoAlO. In addition, owing to the nanosheets-like morphology of 5K/CoAlO, the soot particulates could be highly dispersed on the nanosheets-like layers of 5K/CoAlO and get more access to active components, which is favorable to soot combustion. In summary, the improved amount of active oxygen species and the increased soot-catalyst contact efficiency guarantee the high soot combustion activity of our K supported CoAlO catalysts. Our work provides a novel approach to designing a highly efficient Co-based hydrotalcite-derived oxides catalyst for catalytic soot combustion.