A DFT study of the chain growth probability in Fischer–Tropsch synthesis

The chain growth probability (α value) is one of the most significant parameters in Fischer–Tropsch (FT) synthesis. To gain insight into the chain growth probability, we systematically studied the hydrogenation and CC coupling reactions with different chain lengths on the stepped Co(0001) surface using density functional theory calculations. Our findings elucidate the relationship between the barriers of these elementary reactions and the chain length. Moreover, we derived a general expression of the chain growth probability and investigated the behavior of the α value observed experimentally. The high methane yield results from the lower chain growth rate for C1 + C1 coupling compared with the other coupling reactions. After C1, the deviation of product distribution in FT synthesis from the Anderson–Schulz–Flory distribution is due to the chain length-dependent paraffin/olefin ratio.