MIIT Key Laboratory of Critical Materials Technology for, New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China.
Chemistry. 2019 Mar 15;25(16):4175-4183. doi: 10.1002/chem.201805936. Epub 2019 Feb 18.
A series of multiscale cementite/iron/porous carbon (CIPC-T) composites with extremely low nitrogen content and millimeter-size spherical morphology were prepared by simple carbothermal pyrolysis of resin spheres exchanged with ferric oxalate anions. CIPC-T materials are composed of highly disperse core-shell-structured Fe C/Fe@graphitic carbon (CI@GC) nanoparticles embedded in a porous amorphous carbon framework. A mechanism for the formation of the composites is proposed on the basis of the results of XRD, SEM, TEM, and thermogravimetric analysis. The Fe C content can be easily controlled just by using different carbothermal temperatures. The CIPC-T materials proved to be active as heterogeneous catalysts for oxidation of ethylbenzene to acetophenone and Fenton-like oxidation of methylene blue. For the first time, the role of Fe C in catalytic oxidation was confirmed. The spherical morphology of the composites and magnetic property facilitate separation of the catalyst from the reaction solution. More importantly, no leaching of iron active sites occurs during the reactions and the catalyst can be reused in continuous runs without obvious loss of activity. Such high stability of iron sites in the composites is ascribed to the protecting outer graphitic carbon shell of CI@GC.
一系列具有极低氮含量和毫米级球形形貌的多尺度渗碳体/铁/多孔碳（CIPC-T）复合材料是通过用草酸盐阴离子交换的树脂球的简单碳热裂解制备的。CIPC-T 材料由高度分散的核壳结构的 FeC/Fe@石墨碳（CI@GC）纳米颗粒嵌入在多孔无定形碳骨架中组成。基于 XRD、SEM、TEM 和热重分析的结果，提出了复合材料形成的机理。通过使用不同的碳热温度，可以轻松控制 FeC 的含量。CIPC-T 材料被证明是乙苯氧化为苯乙酮和芬顿样氧化亚甲基蓝的非均相催化剂。首次证实了 FeC 在催化氧化中的作用。复合材料的球形形貌和磁性有利于催化剂从反应溶液中分离。更重要的是，在反应过程中没有铁活性位的浸出，催化剂可以在连续运行中重复使用而没有明显的活性损失。这种复合材料中铁位的高稳定性归因于 CI@GC 的保护性外层石墨碳壳。
