Effect of Carbon Porosity and Cobalt Particle Size on the Catalytic Performance of Carbon Supported Cobalt Fischer–Tropsch Catalysts

Abstract

Cobalt catalysts supported on activated carbon and on carbon nanotubes (CNTs) with different porosities were prepared by an incipient wetness impregnation method and characterized by a series of methods. The samples were reduced and then evaluated in a fixed-bed reactor for Fischer–Tropsch (FT) synthesis. The porosity of the carbon support greatly influenced the microstructure, the reducibility, the dispersion, and the FT performance of the cobalt catalysts. The carbon structure and the cobalt dispersion determined CO conversion. CNTs with larger pore sizes were more stable at high temperature in a H2 atmosphere. The cobalt particle size impacted the CO turnover frequency (TOF) and the C5+ selectivity. Larger cobalt particles (up to 7 nm) resulted in higher TOF and C5+ selectivity; for cobalt particles larger than 7 nm, no such increase in these parameters was seen. The carbon support influenced the C5+ selectivity and the C5+ hydrocarbon distribution. Interestingly, the olefin/paraffin ratio of C2 was lower than that of C3 or C4 and a positive relationship existed between the C2–C4 olefin/paraffin ratio and the C5+ selectivity.

Effects of impregnation strategy on structure and performance of bimetallic CoFe/AC catalysts for higher alcohols synthesis from syngas

“…The TPR profile of 15Co/AC sample exhibited three major peaks of hydrogen consumption at 506 K, 619 K, and a broad one at 770 K respectively. The low temperature peak at 506 K could be attributed to the reduction of Co 3 O 4 to CoO, while the peak at 619 K was assigned to the subsequent reduction of CoO to Co [44]. The broad hydrogen consumption peak at 770 K might be assigned to methanation of the AC support in the presence of metallic Co [45].…”

Effects of Water Addition on CO Hydrogenation Over Zinc-Containing Spinel-Supported Cobalt Catalyst

“…The Co/ZnAl 2 O 4 ÁAl 2 O 3 catalyst exhibits good resistance against steam sintering. [1][2][3][4][5][6][7][8][9][10][11] or hydrogenation of unsaturated organic feedstocks [12,13]. Complex oxides (e.g., AB 2 O 4 spinels) have better resistance against sintering/steam than simple oxides (e.g., silica or alumina) and can minimize the formation of metal-support compounds [14,15].…”

Effects of titanium silicalite and TiO2 nanocomposites on supported Co‐based catalysts for Fischer–Tropsch synthesis

“…The uncondensed gas was reduced to atmospheric pressure by a backpressure valve, and then passed through an Agilent 6820 GC equipped with thermal conductivity and flame ionization detectors for online analysis. The calculations for CO conversion and product selectivity were reported previously …”

“…The calculations for CO conversion and product selectivity were reported previously. [11] 3 | RESULTS AND DISCUSSION 3.1 | Characterization of catalysts…”