Carbon deposition and catalytic deactivation during CO_2 reforming of CH_4 over Co/MgO catalyst

The deactivation mechanism of Co 4 displayed a significant decrease in the initial stage caused by carbon deposition. There were two types of cokes, carbon nanotubes (CNTs) and carbon nano-onions (CNOs). The number of the CNO layers that coated on the surface of Co nanoparticles (NPs) increased rapidly in the initial reforming time, which was responsible for the deactivation of the Co 3 O 4 by O species (OH intermediate, CO 2 , H 2 O) during the reforming reaction, which accelerates the formation of coke that blocked the active metal, thus led to catalyst deactivation