Highly stable Ni/SiC catalyst modified by Al2O3 for CO methanation reaction
Highly stable Ni/SiC catalyst modified by Al2O3 for CO methanation reaction
复制标题
Al2O3 改性高稳定性 Ni/SiC 催化剂用于 CO 甲烷化反应
DOI：
10.1039/c5ra19940a
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发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Su, Fabing
中科院分区：
文献类型：
--
作者：
Jin, Guojing;Gu, Fangna;Su, Fabing
在高放热反应中防止负载型镍催化剂的烧结仍然是一个很大的挑战。针对这一问题，本工作探索了高导热、稳定的碳化硅作为CO甲烷化合成天然气的镍催化剂载体，同时利用Al_2O_3对碳化硅表面进行改性，增强了金属与载体之间的相互作用，抑制了反应过程中镍活性成分的烧结或流失。采用共沉积-沉淀法成功制备了一系列Ni/Al_2O_3-SiC催化剂。采用氮气吸附、X射线衍射仪、扫描电子显微镜/能谱仪、透射电子显微镜、X射线光电子能谱、氢-2-TPR、氢-2-TPD和热重等方法对催化剂进行了表征。H-2-TPR结果表明，引入的Al_2O_3颗粒均匀沉积在碳化硅载体表面，形成了Ni-Al_2O_3络合物，明显增强了Ni与载体之间的相互作用。Al_2O_3含量适中的Ni/Al_2O_3-SiC催化剂表现出较高的催化活性和较强的抗烧结性，这主要归因于两个因素：(1)Al_2O_3的加入可以增强Ni与载体之间的相互作用，从而抑制Ni颗粒在载体表面的迁移，改善其分散性；(2)碳化硅具有良好的导热性能，可以减少催化剂床层热点的产生。
It is still a great challenge to prevent sintering of supported Ni catalysts in highly exothermic reactions. To address this problem, in this work, highly thermal conductive and stable SiC is explored as a Ni catalyst support for CO methanation to produce synthetic natural gas; simultaneously, Al2O3 is utilized to modify the SiC surface to enhance the interaction between the metal and support and restrain the Ni active component from sintering or loss during the reaction. A series of Ni/Al2O3-SiC catalysts were successfully prepared by the co-deposition-precipitation method. The catalysts were investigated by N-2 adsorption, XRD, SEM/EDS, TEM, XPS, H-2-TPR, H-2-TPD and TG. The elemental mapping images indicated that the introduced Al2O3 particles were uniformly deposited on the surface of the SiC support, which evidently enhanced the interaction between Ni and the support by forming Ni-Al2O3 complexes as proved by H-2-TPR results. The Ni/Al2O3-SiC catalyst with an optimal amount of Al2O3 content showed a high catalytic activity and strong resistance to sintering, which can be attributed to two main factors: (1) the addition of Al2O3 can enhance the interactions between Ni and the support, thus inhibiting the migration of Ni particles on the support surface and improving the dispersion of them; (2) the superior heat conductivity of SiC can decrease the generation of hot spots in the catalyst bed.