Fischer–Tropsch catalysts deposited with size-controlled Co3O4 nanocrystals: Effect of Co particle size on catalytic activity and stability
Fischer–Tropsch catalysts deposited with size-controlled Co3O4 nanocrystals: Effect of Co particle size on catalytic activity and stability
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DOI：
10.1016/j.apcata.2011.10.010
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发表时间：
2012-01
影响因子：
5.5
通讯作者：
Jo-Yong Park;Yun-Jo Lee;P. Karandikar;K. Jun;Kyoung‐Su Ha;Hae-Gu Park
中科院分区：
文献类型：
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作者：
Jo-Yong Park;Yun-Jo Lee;P. Karandikar;K. Jun;Kyoung‐Su Ha;Hae-Gu Park
利用预合成的纳米钴氧化物研究了钴颗粒尺寸对费托反应的影响。以Co_3O_4为原料，在150 ~ 250°C的不同反应温度下合成了粒径为3- 16 nm的Co_3O_4纳米粒子。以γ-Al_2O_3为载体制备了5wt%Co/Al_2O_3催化剂，并与传统方法制备的催化剂进行了比较。在4.8 ~ 17.5nm范围内，随着钴晶粒尺寸的增大，TPR还原度和O2-吸收量增大，H2-吸收量减小。当钴晶粒尺寸从4.8增加到9.3nm时，催化活性迅速增长，然后随着晶粒尺寸的进一步增加，催化活性下降，表现出火山状的催化活性。结果表明，Co粒径为9.3nm的催化剂具有较高的CO转化率、较好的C5+选择性和较低的甲烷转化率。与常规催化剂相比，这些尺寸限定的钴催化剂显示出相当高的FTS活性和更好的TOF（S-1），并且随着钴颗粒尺寸的增加，它们的失活速率甚至在54小时后也降低。
The influences of cobalt particle size on the Fischer–Tropsch reaction have been studied by using pre-synthesized cobalt oxide nanoparticles. Cobalt oxide nanoparticles in the range of 3–16nm were synthesized by reacting colloidal solution of Co3O4at the different reaction temperatures from 150 to 250°C and stabilized by capping agent. The nanoparticles were impregnated on γ-Al2O3to prepare 5wt% Co/Al2O3catalysts and compared with the catalysts prepared by conventional methods. The reduction degree by TPR and O2-uptake increased with the increase in the cobalt crystal size from 4.8 to 17.5nm, however H2-uptake decreased. The rapid growth in the catalytic activity was observed when the cobalt crystal size increased from 4.8 to 9.3nm and then the activity decreased with further increase in crystal size showing volcano shape in catalytic activity. The catalyst with the cobalt particle size of 9.3nm showed higher CO conversion, better C5+selectivity and lower methane conversion. These size-defined cobalt catalysts showed considerably higher FTS activity and better TOF (S−1) than conventional catalysts and with the increase in the cobalt particle size, their deactivation rates also decreased as well even after 54h on stream.