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

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>A crucial contribution of Al<SUB>2</SUB>O<SUB>3</SUB> pillar for an enhanced structural stability of a highly ordered mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> (Al/m-Co) for CO hydrogenation activity was verified in terms of newly formed stable phases with their interactions. At an optimal 5 wt%Al<SUB>2</SUB>O<SUB>3</SUB> 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 Co<SUB>3</SUB>O<SUB>4</SUB> structures due to the newly formed strong Al<SUB>2</SUB>O<SUB>3</SUB>-Co<SUB>3</SUB>O<SUB>4</SUB> interactions with the partial formation of the catalytically inactive spinel-type CoAl<SUB>2</SUB>O<SUB>4</SUB> phases in the matrices of the mesoporous Al/m-Co. The main roles of the Al<SUB>2</SUB>O<SUB>3</SUB> pillar on the Al/m-Co were a structural promoter to maintain the highly ordered mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> structures by easily removing the heavy hydrocarbons formed during FTS reaction without significant coke depositions through those large mesopores. The homogeneously distributed Al<SUB>2</SUB>O<SUB>3</SUB> pillaring material less than monolayer on the Al/m-Co surfaces played a crucial role to preserve the original ordered mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> structures through the partial formation of outer surface CoAl<SUB>2</SUB>O<SUB>4</SUB> phases with less blockages of active metallic cobalt sites by heavy coke precursors formed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Al<SUB>2</SUB>O<SUB>3</SUB> pillared ordered-mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> (Al/m-Co) showed a superior FTS activity and stability. </LI> <LI> Enhanced structural stability of Al/m-Co was from the partially formed thermally stable CoAl<SUB>2</SUB>O<SUB>4</SUB>. </LI> <LI> Main role of Al<SUB>2</SUB>O<SUB>3</SUB> pillar was the structural promoter to maintain the ordered Co<SUB>3</SUB>O<SUB>4</SUB> structures. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>