Great activity enhancement of Co3O4/γ-Al2O3 catalyst for propane combustion by structural modulation

Co3O4/gamma-Al2O3 is a high-active catalyst for VOCs combustion, however large numbers of inactive cobalt species will form easily as a result of strong Co/Al interaction which usually leads to a significant activity reduction of the active cobalt species. Here, a facile reduction-passivation approach has been developed to modulate the Co/ Al interaction in 10%Co3O4/gamma-Al2O3 catalyst, which produces abundant active cobalt oxides with rather small particle size stabilized on the surface as a core-shell structure. The catalytic activity for the model reaction of propane combustion could be enhanced greatly by this approach. The weak Co-Al interaction and the highly dispersed Co3O4 on the outer-layer of the core-shell structure contribute mainly to the great activity enhancement. Further, the reduction-passivation treated catalyst also exhibits excellent stability and even a moderate activity increase after prolonged or recycling catalytic tests. The present reduction-passivation treatment can be a promising way to improve the catalytic performance of Co-based catalysts for high temperature catalytic combustion.