Structure sensitivity of the Fischer–Tropsch activity and selectivity on alumina supported cobalt catalysts

Measurement of the Influence of the Microstructure of Alumina‐Supported Cobalt Catalysts on their Activity and Selectivity in Fischer–Tropsch Synthesis by using Steady‐State and Transient Kinetics

“…[10] The results diverge over smaller Co particles, and some research groupsh ave reported ad ecreaseo ft he TOF with decreasing particle size, [6,7,9,14] whereas others do not observe this effect. [3,4,12,13] The cause for this discrepancy has been attributed to al arge range of phenomena such as ap referential oxidation or carbidization of small Co particles, difference in reducibility,f ormation of Co-support mixed compounds, or to an inappropriatem easurement of the surfaceC oa toms.…”

“…Numerous studies have been devoted to gain an understanding of the effect of the support and Co structure on the catalytic performance. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] The precise influence of the catalyst variables remains unclear.T he effect of the Co particles ize on the activity and selectivity is still under debate.…”

Development of the Fischer-Tropsch Process: From the Reaction Concept to the Process Book

“…Alumina is again a rather good compromise as it generates intermediate supportactive phase interactions (compared with silica and titania, for example). Moreover, it has been shown in the literature that in the case of FTS, there is an optimum Co crystallite size whose value varies between 4 and 8 nm depending on the catalyst carrier and reaction conditions (den Breejen et al, 2010;Fischer et al, 2013). Most authors, however, agreed on the necessity to obtain a narrow particle size distribution.…”

Effects of Co/SiO2Particle Size on Fischer-Tropsch Synthesis: Study by TPD and DRIFTS

“…图 9 CoSi-x 催化剂的 CO-TPD 图谱之 CO 2 信号 Figure 9 CO 2 signals of CO-TPD for CoSi-x catalysts 由 F-T 合成反应机理, 催化剂表面烷基物种的 β-H 离去而脱附产生 α-烯; 正构烷烃则是表面烷基物种的加 氢或 α-烯的二次吸附加氢所致 [9,26] . 因较小的 Co 粒子上 的低配位数的 Co 原子较多, 使得 CO 与较小的 Co 粒子 上 Co 原子的结合强度要高于较大的 Co 粒子, 那么催化 剂表面吸附的烷基中间体亦较难发生脱附; 且对比 H 2 -TPD 和 CO-TPD 结果可知, 催化剂表面 H*的浓度远 高于表面 C*的浓度; 较小 Co 粒子表面的 H*/C*高于较 [9] .…”

“…因较小的 Co 粒子上 的低配位数的 Co 原子较多, 使得 CO 与较小的 Co 粒子 上 Co 原子的结合强度要高于较大的 Co 粒子, 那么催化 剂表面吸附的烷基中间体亦较难发生脱附; 且对比 H 2 -TPD 和 CO-TPD 结果可知, 催化剂表面 H*的浓度远 高于表面 C*的浓度; 较小 Co 粒子表面的 H*/C*高于较 [9] . 本文所涉表征与反应均进行过重复性实验, 所得规 律一致.…”