State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences
University of Chinese Academy of Sciences
National Energy Center for Coal to Liquids, Synfuels China Co. Ltd.

在费托合成反应中，Fe基催化剂由于价格低廉、活性高、CH4选择性低等多种优势，被广泛应用于大规模煤炭间接液化工业中。催化性能与催化剂颗粒尺寸、表面结构、成分构成等性质密切相关。还原碳化是铁基催化剂活化的关键步骤，本工作通过改变晶体生长条件，制备了暴露{111}晶面的不同尺寸的Fe3O4-O，以及尺寸接近的Fe3O4-O和暴露{110}晶面的Fe3O4-RD，探究Fe3O4晶粒尺寸以及暴露晶面对碳化过程的影响。结果表明，尺寸达到微米级的Fe3O4-O晶体比50 nm的晶体更难被碳化。利用原位XRD表征尺寸均为150 nm的Fe3O4-O和Fe3O4-RD晶体在还原碳化过程中的物相组成变化，结果显示，两种晶体的碳化速率不同，且可碳化上限不同，因此，晶面取向会影响还原碳化过程。使用TEM表征暴露不同晶面的Fe3O4碳化后的晶体结构，发现两种晶体的形貌均发生改变，形成核壳结构。

In the Fischer-Tropsch synthesis reaction, Fe-based catalysts are widely used in large-scale indirect coal liquefaction industry due to their low price, high activity, and low CH4 selectivity. The catalytic performance is closely related to the catalyst particle size, surface structure and composition. Since reductive carbonization is a key step in the activation of iron-based catalysts, in this work, Fe3O4-O (expose the {111} crystal planes) with different particle size, and similar particle size but exposing different crystal planes, {111} and {110} (Fe3O4-RD), have been prepared to explore the effect of particle size and surface structure on the carbonization process. The results show that the 50 nm Fe3O4-O particles change more significantly than the one with large particle size (2–10 μm) after carbonization. In-situ XRD was used to monitor the phase change of Fe3O4 with exposing different surface planes during carbonization. The results show that 150 nm Fe3O4-O and Fe3O4-RD particles behave differently in carbonization rate and have different iron carbide concentration in the end, which indicates the carbonization process can be affected by exposed crystal planes. TEM analysis reveals that Fe3O4@FexC core-shell structure formed after carbonization.

国家自然科学基金 (21972162, 22025804)和准格尔旗科技重大专项项目(2022ZD-03) 资助

李思琪, 魏旭松, 王洪, 青明, 索海云, 吕振刚, 过会闯, 刘颖, 于欣, 杨勇, 李永旺. Fe3O4晶体碳化过程中的晶面效应[J]. 燃料化学学报（中英文）, 2023, 51(9): 1282-1290.

LI Si-qi, WEI Xu-song, WANG Hong, QING Ming, SUO Hai-yun, LÜ Zhen-gang, GUO Hui-chuang, LIU Ying, YU Xin, YANG Yong, LI Yong-wang. The effect of crystal plane on Fe3O4 carbonization[J]. Journal of Fuel Chemistry and Technology, 2023, 51(9): 1282-1290.