碳基纳米笼负载的新型复合催化剂构建及其性能研究

With the support of the just-finished NSFC project, some important progresses have been obtained in the controllable preparation of carbon-based nanocages and its energy-directed functionalization. For example, carbon-based nanocages with a series of peculiarities are prepared controllably, including high surface area, large pore volume, well-graphitized degree, rich surface defects, and adjustable hetero-atom content and status. Based on these research progresses, this NSFC application mainly focuses on the construction and catalytic properties of new carbon-based nanocages loaded catalysts for the two probe reactions of Fischer-Tropsch synthesis of light olefins and the selective oxidation of benzyl alcohol to benzaldehyde. Taking advantage of the adjustable electronic structures of nanocages by doping, as well as the coordination and anchoring effect of hetreo atom for catalytic active species, the nanocages as a novel catalyst support are used to construct the iron- or ruthenium-based composite catalysts. Their catalytic performance will be systematically investigated. The correlations between the catalytic performance and the composition and structures of the catalysts will be studied in depth， especially on the effects of the electronic structures of the nanocages.The interactions between the nanocage supports and the catalytic active species are also studied. The catalytic mechanism and regulation mechanisms will be explored tentatively. By this project, these results should be helpful to direct the design and development of the novel carbon nanocage-based catalysts with excellent performance. In addition, one can expect the creative and systematic achievements with self-owned intellectual property rights about the catalysts of carbon-based nanocages.

在刚结题的国家自然科学基金资助下，申请人在碳基纳米笼可控制备和能源导向的功能化研究方面取得重要进展，获得的碳基纳米笼具有表面积高、孔容大、石墨化程度好、表面缺陷丰富、便于掺杂调变等优点，且在多个催化反应中初步展示出优良的催化性能。在此基础上，本项目重点以费托合成制低碳烯烃、选择氧化苄醇制苯甲醛为探针反应，利用碳基纳米笼的电子结构易于掺杂调控、杂原子对催化活性组分具有配位或锚定作用等特点，着重构建碳基纳米笼负载的铁基、钌基纳米复合催化剂，探索构建规律，考察催化性能，深入研究催化性能与成分结构的关系(尤其是碳基纳米笼电子结构的影响)，揭示载体与活性组分的相互作用、催化剂的催化作用机理和调控机制，为设计和开发先进的新型碳基纳米复合催化剂提供科学依据，并优化出高性能的碳基纳米笼复合催化剂。

以碳纳米管为代表的新型碳纳米材料在设计和开发新型碳基纳米催化剂的研究取得一系列重要进展，但碳基纳米管存在比表面积小、不利于催化活性组分的分散等瓶颈问题。本项目拟以费托合成制低碳烯烃等作为探针反应，利用碳基纳米笼结构和组成可调的特点，着重构建碳基纳米笼负载的铁基、钌基纳米复合催化剂，探索构建规律，考察碳基纳米笼纳米复合催化剂的催化性能，深入研究催化性能与催化剂成分、结构的关系，揭示载体与活性组分的相互作用、催化作用机理和调控机制。. 本项目在执行过程中很好地完成了既定的研究目标。主要进展包括：（1）可控地制备出形貌、结构和组成可调的碳基纳米笼，首次提出借助毛细作用力有效地调控其分级孔结构中微孔、介孔和大孔的比例，为制备合适孔分布的碳基材料提供依据；（2）利用碳基纳米笼的结构和组成可控的特点，方便地构建出限阈型和负载型Fe、Ru和Pt基复合催化剂，譬如：利用hNCNC笼壁微孔的陷阱作用和微孔边沿吡啶氮锚定作用的协同，在温和的溶液条件下制备出单原子Pt1/hNCNC催化剂。（3）Fe/hNCNC展现出优异的费托合成制低碳烯烃催化性能，发现氮掺杂有利于提高铁纳米颗粒分散性、低碳烯烃选择性、催化剂的抗烧结和抗积碳性能。（4）首次揭示出在费托合成反应过程中碳化铁颗粒烧结的羰基铁介导的类奥斯瓦尔德熟化机制，以此为指导，通过控制hNCNC氮掺杂量，可控地设计和制备出抗烧结催化剂。（5）碳基纳米笼负载的Ru基催化剂在温和条件下展现出优异的选择氧化苄醇制苯甲醛、苯乙酮选择加氢制苯乙醇等反应的催化性能，催化活性和目标产物选择性都接近100 %。（6）作为无金属催化剂，在选择氧化乙苯制苯乙酮、电催化硫高效转化等方面展现出优异的性能，譬如：巧妙地将‘物理限域’、‘化学吸附’、‘催化转化’等功能集成于一体，在S@hNCNC上实现了相互促进的高效协同，有效地抑制了极化效应、穿梭效应，为揭示相关作用机理及性能调控机制、获得高功率长寿命锂硫电池电极材料提供指导。