Fe_(3)O_(4)晶体碳化过程中的晶面效应  

The effect of crystal plane on Fe_(3)O_(4) carbonization

作　　者：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[1,3] 李永旺 LI Si-qi;WEI Xu-song;WANG Hong;QING Ming;SUO Hai-yun;LÜZhen-gang;GUO Hui-chuang;LIU Ying;YU Xin;YANG Yong;LI Yong-wang(State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;University of Chinese Academy of Sciences,Beijing 100049,China;National Energy Center for Coal to Liquids,Synfuels China Co.Ltd.,Beijing 101407,China)

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001 [2]中国科学院大学,北京100049 [3]中科合成油技术股份有限公司国家能源煤基液体燃料研发中心,北京101407

出　　处：《燃料化学学报（中英文）》2023年第9期1282-1290,共9页Journal of Fuel Chemistry and Technology

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

摘　　要：在费托合成反应中,Fe基催化剂由于价格低廉、活性高、CH_(4)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Fe_(3)O_(4)-O,以及尺寸接近的Fe_(3)O_(4)-O和暴露{110}晶面的Fe_(3)O_(4)-RD,探究Fe_(3)O_(4)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Fe_(3)O_(4)-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Fe_(3)O_(4)-O和Fe_(3)O_(4)-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Fe_(3)O_(4)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,Fe_(3)O_(4)-O(expose the{111}crystal planes)with different particle size,and similar particle size but exposing different crystal planes,{111}and{110}(Fe_(3)O_(4)-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 Fe_(3)O_(4)-O particles change more significantly than the one with large particle size(2–10μm)after carbonization.In-situ XRD was used to monitor the phase change of Fe_(3)O_(4) with exposing different surface planes during carbonization.The results show that 150 nm Fe_(3)O_(4)-O and Fe_(3)O_(4)-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 Fe_(3)O_(4)@FexC core-shell structure formed after carbonization.

关 键 词：Fe_(3)O_(4) 晶面效应 原位XRD 碳化 

分 类 号：O643.36[理学—物理化学]