Roles of Al2O3 promoter for an enhanced structural stability of ordered-mesoporous Co3O4 catalyst during CO hydrogenation to hydrocarbons

Abstract

A crucial contribution of Al2O3 pillar for an enhanced structural stability of a highly ordered mesoporous Co3O4 (Al/m-Co) for CO hydrogenation activity was verified in terms of newly formed stable phases with their interactions. At an optimal 5 wt%Al2O3 on the Al/m-Co, the activity and stability of Fischer-Trospch synthesis (FTS) reaction were largely enhanced by preserving the highly ordered original mesoporous Co3O4 structures due to the newly formed strong Al2O3-Co3O4 interactions with the partial formation of the catalytically inactive spinel-type CoAl2O4 phases in the matrices of the mesoporous Al/m-Co. The main roles of the Al2O3 pillar on the Al/m-Co were a structural promoter to maintain the highly ordered mesoporous Co3O4 structures by easily removing the heavy hydrocarbons formed during FTS reaction without significant coke depositions through those large mesopores. The homogeneously distributed Al2O3 pillaring material less than monolayer on the Al/ m-Co surfaces played a crucial role to preserve the original ordered mesoporous Co3O4 structures through the partial formation of outer surface CoAl2O4 phases with less blockages of active metallic cobalt sites by heavy coke precursors formed.