二氧化铈担载镍纳米催化剂的等离子体制备及其在甲烷干重整中的晶面效应研究

Carbon dioxide (dry) reforming of methane can not only produce synthesis gas (syngas) with a H2/CO ratio of 1, but also consume effectively two major greenhouse gases, which are of great benefit to both environment and economy. The major obstacle for industrialization of the methane dry reforming over Ni-based catalysts is the rapid deactivation of catalysts caused by carbon deposition. In order to suppress the carbon deposit on the catalyst, we will study the catalyst from two aspects: 1) We intend to clarify the mechanism of methane conversion over conventional Ni-CeO2 catalyst. The reaction pathway of methane is the fundamental problem of carbon deposition, so the reaction mechanism over conventional Ni-CeO2 catalyst will be explored. The pathway of methane conversion over Ni-CeO2 catalyst and the transformation regularity of intermediate carbon species will be revealed, which can provide a theoretical basis for the structural design of Ni-CeO2 catalyst. 2) We plan to construct Ni-CeO2 catalyst with the specific structure-activity relationship. According to the key problems that the CHx generated from methane can be easily transformed into inert carbon, CeO2 support material that exposed specific crystal planes will be prepared. The structure-activity relationship between the crystal surface and anti-carbon performance will be established, and the accurate control of intermediate carbon species will be realized. The modulation mechanism of plasma technology on dispersion and stability of nano metal Ni will be studied in order to anchor the active component on the particular crystal face of CeO2 support. The catalyst structure will be optimized, expecting to obtain innovative achievements in the development of novel and efficient catalyst system.

甲烷干重整反应既可制得H2/CO为1:1的合成气，又可综合利用这两大温室气体，利于缓解温室效应且取得可观经济收益。针对该反应中Ni基催化剂容易积碳失活，本项目将从两个方面研究：1) 阐明催化剂上甲烷的转化机制。基于积碳问题的根本是甲烷反应路径问题，本研究拟探索常规Ni-CeO2催化剂在反应过程中的作用机制，揭示Ni-CeO2催化剂上甲烷反应路径和中间碳物种转化规律，为Ni-CeO2结构催化剂的设计提供理论依据。2) 构建特定构效关系的Ni-CeO2催化剂。针对甲烷反应产生的CHx极易转化成惰性碳的关键问题，制备暴露特定晶面的CeO2载体材料，建立晶面和抗积碳性能之间的构效关系，实现对中间碳物种的准确控制。研究等离子体强化技术对金属Ni在纳米尺度上分散性与稳定性的调控机制，实现活性组分与载体特定晶面的键合锚定作用，优化催化剂结构，在开发新型高效催化剂体系方面以期取得创新性的基础成果。

甲烷干重整反应既可制得H2/CO为1:1的合成气，又可综合利用这两大温室气体，利于缓解温室效应且取得可观经济收益。针对该反应中Ni基催化剂容易积碳失活，本研究构建了特定构效关系的Ni-CeO2催化剂。针对甲烷反应产生的CHx极易转化成惰性碳的关键问题，制备了暴露特定晶面的CeO2载体材料，实现了对中间碳物种的准确控制，获得了良好的甲烷干重整反应性能和催化稳定性，在开发新型高效催化剂体系方面取得了创新性的基础成果。. 芳烃是产量仅次于乙烯和丙烯的重要有机化工原料，甲醇转化制芳烃（MTA）是合成优质芳烃的重要途径。本研究探究了分子筛在MTA反应中对催化性能和产物分布的晶面选择效应，制备了一系列具有相似孔结构、酸性位和a轴长度，不同b轴长度的分子筛，使用高分辨EELS表征了单晶MFI分子筛不同晶面上积碳的化学属性，首次发现了不同晶面上的积碳物种，将积碳信息和C1-C4气态物种以及C6-C9芳烃产物进行了关联，为进一步理解分子筛催化剂提供了有力的工具。此外，针对目前常规法制备的分子筛成本高、抗积碳能力差和芳烃选择性低等缺点，开发了新型的大孔-介孔-微孔多级ZSM-5的合成路径，并对其晶化过程、结构表征以及MTA催化性能等进行了详细的研究。