ZIF-67 as precursor to prepare high loading and dispersion catalysts for Fischer-Tropsch synthesis: Particle size effect. (1st April 2019)

• Record Type: Journal Article
• Authors: Chen, Yao; Li, Xin; Nisa, Mehar U; Lv, Jing; Li, Zhenhua
• Is Part Of: Fuel. Volume 241(2019)
• Page Start: 802
• Page End: 812
• Publication Date: 2019-04-01
• Subjects: Cobalt -- Fischer-Tropsch synthesis -- ZIF-67 -- Co@C -- Particle size; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.12.085
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Particle size of ZIF-67 was modified by changing the amount of CTAB. ZIF-67 was used as a precursor to prepare the Co@C catalyst with not only high cobalt loading but also good dispersion. The number of active sites on Co@C catalyst varied with the particle size of ZIF-67, then influenced the FTS performance. Abstract: A series of cobalt embedded in nano-porous carbons (Co@C) with different particle sizes have been synthesized by one-step carbonization of metal-organic-framework (MOFs) ZIF-67. The particle size of Co@C can be determined by its precursor which is modified by the content of CTAB (cetyltrimethyl ammonium bromide). The as prepared catalysts were characterized by XRD, N2 adsorption-desorption, SEM, TEM, TGA and H2 -TPR, showing not only high loading but also superior dispersion. The Co@C catalysts have similar morphology with their corresponding precursors, on which highly dispersed cobalt was achieved even at high Co loading. The particle size of Co@C catalyst decreases with the increase of CTAB content. When CO conversion is plotted as a function of CTAB content, a volcano-like curve is obtained with an optimum CTAB content at m(CTAB) /n(Co) = 8 (m stands for the weight of CTAB, n stands for the moles of cobalt). Among these catalysts, the 8CTAB-Co@C catalyst exhibited the smallest Co crystalline size, best Co dispersion and highest CO conversion, while the 16CTAB-Co@C catalyst showed the lowest activity due to the biggest cobalt crystalline size.