溢流氧对甲烷重整反应中镍基催化剂的消碳作用

The development of coke-resistant nickel-based catalysts for syngas production by methane reforming has long been the center of utilization and conversion of methane in industries. Based on the previous research work of Mg-La mixed oxides supported nickel-based catalysts in dry methane reforming reaction, this project aims at the further investigation of the effect of spillover oxygen on the carbon removal over the same catalysts. For this purpose, this project will take the advantage of the unique property of Mg-La mixed oxides supported nickel-based catalysts where the active sites (lanthanum oxide) for oxygen species and the active sites (metal nickel) for methane are separated, so that the number and type of spillover oxygen can be precisely controlled by adjusting the number of the active sites influenced by the nature of the interface of lanthanum oxide. Using a variety of experiments and characterization methods, such as isotope exchange reaction, pulse switching response reaction, steady state isotopic transient kinetic surface analysis, accurate and quantitative measurements of the effect of the oxidizing capability and fluidity of different types of spillover oxygen on the removal of different types of carbon can be achieved. The mechanism of the enhanced coking resistance of catalysts by spillover oxygen can also be revealed accordingly. The results of this research project not only provide an approach to use spillover oxygen for carbon removal, but also pave a way to the development of methane reforming catalysts with high activity, stability and resistance to coking.

甲烷重整制合成气反应中镍基催化剂抗积碳性能的研究一直是甲烷转化利用工业化的关键。基于前期对镁镧复合氧化物负载的镍基催化剂在甲烷二氧化碳重整反应中的研究，本项目将深入拓展此镍基催化剂中溢流氧对积碳消除作用的研究。课题将利用镁镧复合氧化物负载的镍基催化剂中氧物种活性中心(氧化镧)和甲烷活性中心（金属镍）相分离的独特结构，通过研究氧物种活性中心的界面性质对氧活性位点数量的影响，来精确控制溢流氧的数量和类型。采用同位素交换、脉冲切换反应、稳态同位素瞬变动力学表面分析技术等多种实验和表征手段，准确定量地测定不同类型溢流氧的氧化性和流动性对不同类型积碳的消除作用，揭示溢流氧对提高催化剂抗积碳能力的机理。课题的研究成果将提供一种利用溢流氧消碳的方法，为研制高活性、高稳定性、抗积碳性能强的甲烷重整催化剂奠定基础。

甲烷重整制合成气反应中镍基催化剂抗积碳性能的研究一直是甲烷转化利用工业化的关键。本研究发现镁镧复合氧化物载体中Mg-La的强相互作用有利于Mg对La2O3的晶格进行掺杂，在La2O3的晶格中产生氧缺陷，进而发生电子从La2O3到MgO的转移，使得MgO表面电子富集，吸附态氧的含量增加。吸附态氧含量的增加有利于产物氢气的氧化反应，推动反应的进行；同时，可以促进M-La2O2CO3的活化，提高甲烷的反应活性，抑制反应中积碳的生成。此外，通过调节金属镍和载体的相互作用，可以进一步提高催化剂的活性和稳定性。课题的研究成果将为研制高活性、高稳定性、抗积碳性能强的甲烷重整催化剂奠定基础。