Improvement of the Fischer–Tropsch Synthesis Activity of Co/SiO2 Catalyst by the Stepwise Impregnation Method with Chelating Agents

Abstract

Co/SiO 2 catalysts were prepared by a stepwise impregnation of aqueous solutions containing Co nitrate or chelating agent, nitrilotriacetic acid (NTA) or trans-1,2-diaminocyclohexane-N,N,N 0 ,N 0 -tetraacetic acid (CyDTA), with various concentrations of Co 2+ and the chelating agent. Fischer-Tropsch synthesis activity of Co/SiO 2 catalysts having Co loadings of 5-20 mass% as metallic Co was improved by the stepwise impregnation method with these chelating agents. The catalyst prepared with CyDTA (Co loading = 20 mass%, Co 2+ /CyDTA = 4 mol mol -1 ) yielded 1,500 and 815 g kg-cat -1 h -1 of C 5+ and C 10-20 hydrocarbons at 503 K and 1.1 MPa, respectively, which was much greater than that with the catalyst prepared from the aqueous solution containing both Co nitrate and NTA.

Preparation of Co/SiO2 Using Several Glycols for Enhanced Fischer-Tropsch Synthesis Activity and Dispersion of Co0 Nanoparticles with Unique Co0 Particle Size Effect

“…[23][24][25][26][27][28]. FTS activity was enhanced by a factor of 3-4 in the presence of these chelating agents having strong interaction with Co 2?…”

Enhancing the Fischer–Tropsch Synthesis Activity of Co-based Catalysts by Adding ZrO x to the SiO2 Support and Chelating Ligands to the Co-precursor

“…On the other hand, the stepwise impregnation method was applied to the chelate-assisted catalysts with high Co content (20 mass% as metallic Co) due to the low solubility of the chelating agents in water in the presence of Co nitrate. Details of the stepwise impregnation method can be found elsewhere [19,21]. For the catalyst prepared using glycols, the co-impregnation method was used regardless the Co content of the catalysts [22,23].…”

“…In our previous work [19][20][21][22][23], we found that the chelateor glycol-assisted catalysts with Co content of 20 mass% also exhibited higher FTS activity than catalysts prepared without using these organic additives. The effects of combination of the organic additives and ZrO x modification on the activity of the catalysts with higher Co content of 20 mass% were also investigated.…”

“…molar ratio of 0.25. This molar ratio was optimized at Co(20)-CyDTA(Y)/SiO 2 [19]. As summarized in this figure, cooperative effect of the organic additive and ZrO x modification worked only in Co(20)-CyDTA(0.25)/ZrO x /SiO 2 ; activity enhancement induced by combining CyDTA and ZrO x was larger than those induced by CyDTA or ZrO x alone.…”

“…[15][16][17][18][19][20][21]. FTS activity was enhanced by a factor of 3-4 in the presence of these chelating agents having strong interaction with Co 2?…”