石墨型氮掺杂碳材料可控制备及其催化丙烷氧化脱氢制丙烯性能研究

Carbon materials have drawn a great deal of attention for the application as metal-free catalysts of activation of light alkanes in recent years. The low electronegative dopants like boron or phosphorus oxides modified on carbon nanotubes surface will lead to a high selectivity of alkenes but a quite low catalytic activity in the oxidative dehydrogenation (ODH) of propane, owing to the suppression of the formation of highly reactive electrophilic oxygen species. In contrast, the high electronegative nitrogen atoms doped into the graphitic lattice will promote catalytic activity of carbon materials. However, the nitrogen doped carbons was rarely explored in the high-temperature ODH reaction field. The catalytic mechanism of nitrogen doped carbons is also unclear. Aiming to a highly active and selective catalyst for ODH of propane, a series of carbons doped mainly with graphitic nitrogen species will be controllably prepared by a process of hard-templet synthesis, oxidative purification and defects repair in this project. The spatial distribution，bonding configurations and electronic structure of N atom as well as interaction with carbon atoms will be investigated by advanced characterization technologies. The structure-activity relationship will be quantitatively described by combining the structural parameters of doped carbons and the intrinsic constants of propane ODH reaction obtained by kinetic study. The modulation effect of graphitic nitrogen functionality in carbon catalysis will be revealed finally by the structure-activity relationship and supplemented by computer simulation. This project mainly focuses on the controllable synthesis and structure-activity relationship, which will provide theoretical and practical support for design high-efficiency catalyst for activation of light alkanes.

碳材料作为非金属催化剂用于低碳烷烃活化反应日益受到重视。低电负性的硼、磷氧化物修饰碳催化剂表面，能提高烯烃选择性，但由于抑制了高活性亲电氧物种的产生，从而大幅降低了碳材料的活性。高电负性氮原子掺入石墨结构后使得碳材料反应活性更高，但掺氮碳材料在高温烷烃氧化脱氢领域的研究还很少，催化机理不明确。本项目以构建高活性和选择性丙烷氧化脱氢催化剂为出发点，拟采用硬模板法合成、氧化纯化和高温缺陷修复可控制备石墨型氮掺杂的纳米碳催化剂，通过各种表征技术识别氮原子所处的空间位置、键合方式、电子结构及其与碳原子的作用机制，通过反应动力学实验获取丙烷氧化脱氢反应的本征常数。最后结合结构参数和动力学常数定量描述碳催化反应中的构效关系，并辅以计算机模拟验证揭示石墨氮物种对碳材料催化作用的调变机制。本项目通过对“可控制备、构效关系”两方面进行深入研究，为低碳烷烃活化高效催化剂设计提供理论和实践依据。

本项目以构建高活性和选择性丙烷氧化脱氢催化剂为出发点，采用硬模板法合成、臭氧氧化和高温缺陷修复可控制备石墨型氮掺杂的纳米碳催化剂，通过各种表征技术获得了氮原子所处的空间位置、键合方式、电子结构及其与碳原子的作用机制。通过反应动力学实验获取丙烷氧化脱氢反应的本征常数，与结构参数进行关联获取构效关系，并辅以计算机模拟验证揭示石墨氮物种对碳材料催化作用的调变机制。此外，将氮掺杂纳米碳催化剂推广到其他气相催化氧化过程中，更加全面地理解石墨氮物种的催化作用。本项目通过对可控制备和催化氧化两方面的深入研究，为高效碳催化剂设计提供理论和实践依据。