新型有序介孔金属碳化物-氧化物材料的可控制备及催化异丁烷脱氢

Production of isobutene from isobutane is becoming a highly effective pathway with the diminishment of petroleum resources. Up to now, this reaction is industrially performed by Cr-based or Pt-based catalysts. However, the catalysts are prone to rapid deactivation due to coking and sintering. Moreover, Cr-based catalyst is harmful to the environment, while high cost and recycle of waste Pt-based catalyst limit its large-scale applications. Recently, some materials as Pt are found and transition metal carbide (known as eka-platinum metal) in particular. In this project, a novel ordered mesoporous metal carbide-oxide catalyst will be designed to achieve high activity and stability, friendly environment as well as low cost in isobutane dehydrogenation. Specifically, the confinement effect of the ordered mesoporous metal oxides is employed to limit the transition metal carbide into mesoporous framework and/or mesoporous pore channel. The structure and acid-base properties of the catalyst can be adjusted by additives. Aiming to prepare an effective ordered mesoporous metal carbide-oxide catalyst for dehydrogenation, systematic investigations including the key factors in controllable preparation and the relationship between the catalyst structure and its catalytic performances will be carried out. The influence of preparation and reaction conditions on the catalytic performances, the in-depth understanding of deactivation behavior as well as the mechanism of reduction–carburization and dehydrogenation over the ordered mesoporous metal carbide-oxide catalysts will be mainly studied. This work will provide theoretical guidance for exploring the catalysts over dehydrogenation of light alkanes.

异丁烷催化脱氢制异丁烯具有巨大的应用前景和研究价值。目前工业上用于该反应的催化剂主要为Cr基和Pt基催化剂。反应中催化剂易发生积碳和烧结而快速失活，且Cr基催化剂会对环境造成严重危害，Pt基催化剂的高昂价格和废旧催化剂回收技术限制了其更大规模应用。针对以上问题，本项目拟设计和研制一种环境友好、成本低廉的高效有序介孔金属碳化物-氧化物催化新材料。利用有序介孔金属氧化物的限域效应、均一孔道和大比表面积将过渡金属碳化物（类Pt金属）限域在介孔骨架和介孔孔道中，通过助剂调节催化剂结构和酸碱性能，旨在提高催化剂的活性与稳定性。本项目拟通过多种谱学和原位表征及固定床反应评价，对催化剂可控制备和异丁烷脱氢反应中的科学问题进行研究。通过关联构效关系，深入理解催化剂失活机制并建立再生活化方法，在此基础上对催化剂还原碳化和异丁烷脱氢机理进行深入探讨。该工作将为开发低碳烷烃脱氢催化剂提供理论指导。

本项目对异丁烷催化脱氢制异丁烯反应过程开展了系统的研究，开发了环保型有序介孔Mo基和Fe基氧化物及碳化物催化剂，旨在解决目前工业上铬系和铂系催化剂分别存在的重污染、高成本和积碳失活等问题。通过一系列表征手段系统研究了催化剂的结构与脱氢性能之间的关系，探讨了催化剂的失活机制，从而获得了具有良好催化稳定性的异丁烷脱氢新材料。并在理解催化脱氢性能的基础上深入探讨了催化剂上的异丁烷脱氢活性位点。除了完成计划书的既定目标外，还开展了异丁烷的低温脱氢性能研究，初步进行了催化剂的短期寿命试验，获得了良好的反应效果。对该脱氢反应体系及催化剂的研究，为潜在的工业应用积累了基础数据，同时也为开发新型的烷烃脱氢环保型替代催化剂提供了理论基础和技术借鉴。