all the catalysts exhibit maximum selectivity to C2–4 olefins,
indicating that smaller pore size impedes hydrogenation, but facilitates
hydrogen abstraction and chain growth via inserting CH2 groups to produce
olefins with short chain. Especially, Fe–0.9Ag catalyst with pore
size of 1.33 nm provides a high ratio of olefin to paraffin in the C2
through C4 range, and the corresponding value reaches to 5.7.With increasing
the pore size from1.33 to 1.62 nm, the ratio of olefins decreases
to 4.2 (Fe–0.6Ag), and then to 3.4 (Fe–1.3Ag, 2.10nm)