Relation between hydrocarbon selectivity and cobalt particle size for alumina supported cobalt Fischer–Tropsch 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

“…Am ore industrial support, alumina, has been used in as tudy by Holmen et al who did not find any effect of the particle size on the site-time yield but found an optimum for the C 5+ + selectivity. [11,12] However,C laeys et al found that both the activity ands electivity depended on the Co particles ize between 2-10 nm. [14] Recently,t hey stressed the particle-size-dependent role of water on the activity,s electivity,a nd stability of alumina-supported Co catalysts.…”

“…[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. For the latter issue, Yang et al have compared H 2 and CO chemisorption methods to determine the Co particles ize.…”

“…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.…”

Structure of Co(II) Species Formed on the Surface of γ-Alumina Upon Interfacial Deposition

“…low temperature FischerTropsch synthesis or dry reforming of methane [1][2][3][4][5][6][7][8][9][10][11][12][13]). The catalytic activity of these catalysts is strongly related with the characteristics of Co phase, and thus with the preparation method, mainly with the impregnation-deposition procedure followed [14].…”

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

“…同等反应条件下, 随着催化剂中 Co 粒子尺寸的增 大, CO 转化率减小, CO 2 和烯/烷比(O/P)升高, CH 4 选择 性减小, 5 C ＋ 选择性有最大值 [14,32] ; 表观 TOF 值在 d Co ＝8 nm 处最大 [7,33] , 具体见表 6. CO 转化率随 Co 粒子尺寸的增大而减小是由于暴 露于表面的金属 Co 原子数减少, 使催化剂表面的反应 位点数较少; 但 CO 转化率并未与表面暴露的 Co 原子 数呈单调关系, 催化剂 CoSi-085 和 CoSi-090 两者的表 面暴露 Co 原子相差约 20%, 而 CO 转化率却只差约 1%.…”