Structure-Performance Evolution of Cobalt-Ammonia Activated Carbon Catalyst for Ethylene Oligomerization.

The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated in detail. It was found that the catalytic activity sharply decreased in the first 30 h with the ethylene conversion decreasing from 64 to 4%. Butene selectivity increased gradually in the first 10 h then remained about 74%, while the selectivity for hexene and octene exhibited an opposite trend. The ratio of α-olefin to isomers for butene increased greatly with time on stream and most of the generated butene was 1-butene. Based on the structure characterization at different reaction stages, CoOx was suggested to be major active phase and the coverage of long-chain hydrocarbons as well as the loss of surface CoOx active sites due to size growth of Co3O4 nanoparticles were the main reasons for catalytic deactivation. The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated and the coverage of long-chain hydrocarbons as well as the loss of surface CoOx active sites due to size growth of Co3O4 nanoparticles were the main reasons for catalytic deactivation [ABSTRACT FROM AUTHOR]