Descriptors for High-Performance Nitrogen-Doped Carbon Catalysts in Acetylene Hydrochlorination
Descriptors for High-Performance Nitrogen-Doped Carbon Catalysts in Acetylene Hydrochlorination
复制标题
DOI：
10.1021/acscatal.7b03031
复制
发表时间：
2018-02-01
期刊：
影响因子：
12.9
通讯作者：
Perez-Ramirez, Javier
中科院分区：
文献类型：
--
作者：
Lin, Ronghe;Kaiser, Selina K.;Perez-Ramirez, Javier
掺氮碳材料具有广阔的应用前景。然而，由于缺乏有效的方法来控制氮的形态，这极大地阻碍了它们的合理设计，这不仅引起了对特定氮官能团的作用的争议，也阻碍了对这些材料的其他物理化学性质的研究。在这里，我们提出了一种先进的策略，允许系统地调节聚苯胺衍生的氮掺杂碳的导电性，在定义的氮的形态和含量，以及类似的多孔性。通过将这些模型体系应用于聚氯乙烯生产的主要工业技术--乙炔盐化反应，我们深入了解了该反应的活性中心和反应机理，并揭示了该反应中氮掺杂碳的两个关键催化参数：(I)高含量的吡咯-N官能团，促进了反应物的吸附；(Ii)良好的导电性，可能影响吸附物种的表面扩散。由于增加电导率会导致氮含量降低，因此必须仔细控制这两种性质之间的相互作用，以最大限度地提高催化性能。这一认识促成了第一个氮掺杂碳催化剂的设计，该催化剂在乙炔盐化反应中可与基准金基系统前所未有的活性相媲美。
Nitrogen-doped carbons are promising materials for a broad range of applications. However, their rational design is greatly hampered by the lack of efficient methods to control the nitrogen speciation, which not only causes controversy about the roles of specific nitrogen functionalities but also hinders investigations into other physicochemical characteristics of these materials. We herein present a cutting-edge strategy that allows a systematic tuning of the electrical conductivity of polyaniline-derived N-doped carbons at a defined nitrogen speciation and content, and similar porous properties. By application of these model systems in acetylene hydrochlorination, a major industrial technology for the production of polyvinyl chloride, we provide insights into the active sites and the reaction mechanism and disclose two key catalytic descriptors for N-doped carbons in this reaction: (i) a high content of pyrrolic-N functionalities, promoting the adsorption of the reactants, and (ii) good electrical conductivity, likely influencing the surface diffusion of adsorbed species. Since increasing the electrical conductivity leads to a reduced nitrogen content, the interplay between these two properties must be carefully controlled to maximize catalytic performance. This understanding enabled the design of the first N-doped carbon catalyst that rivals the unprecedented activity of benchmark gold-based systems in acetylene hydrochlorination.