US EPA

4787069 

Journal Article 

CO2 hydrogenation to hydrocarbons over Co and Fe-based Fischer-Tropsch catalysts 

Visconti, CG; Martinelli, M; Falbo, L; Fratalocchi, L; Lietti, L 

2016 

Yes 

Catalysis Today
ISSN: 0920-5861 

277 

161-170 

10.1016/j.cattod.2016.04.010 

WOS:000385594800020 

The performances of representative Co-based and Fe-based-Fischer-Tropsch catalysts have been comparatively investigated in the hydrogenation of CO and CO2. Over an un-promoted Co/gamma-Al2O3 catalyst, CO2 is easily hydrogenated and its conversion rate is even faster than that of CO; however, the selectivities of the two processes are extremely different, with methane largely dominating the product distribution in the case of CO2 hydrogenation and long-chain hydrocarbons dominating the products pool during CO hydrogenation. As opposite to cobalt, CO2 hydrogenation rate over K-promoted 100Fe/10Zn/1Cu (at/at) catalysts is slower than that of CO, but the products are dominated by middle distillates when CO2 replaces CO in the feed. Such behaviors depend on the different adsorption strengths of CO and CO2, which affect the H/C atomic ratio on the catalyst surface. In the case of Fe-based catalyst, we have also found that the catalytic sites active in the chain growth process (iron carbides) are transformed into sites active in the hydrogenation reactions (iron oxides/reduced iron centers) at low CO partial pressures. Potassium has a key role in promoting the stability of chain growth sites, thus decreasing the secondary reactions of olefins. (C) 2016 Elsevier B.V. All rights reserved. 

CO2 hydrogenation; Iron catalyst; Cobalt catalyst; Fischer-Tropsch synthesis; Potassium