Carbon-coated Al2O3 supported Co3O4 nanoparticles for Fischer-Tropsch synthesis: Effect of surface carbon properties

[Display omitted] •A series of carbon-coated alumina supports (Al2O3@C-X) with different coating properties were synthesized by modulated carbonization temperature.•The model catalysts (Co/Al2O3@C-X) have the same Co3O4 particle size but differ in the cobalt-support interfacial structure.•The C-O species on the surface of the carbon layer decreased with increasing carbonization temperature.•Carbon coated Al2O3 could reduce CH4 selectivity and increase C5+ selectivity. A series of carbon-coated alumina supports (Al2O3@C-X) with different coating properties were synthesized by modulated carbonization temperatures (600, 800, 1000, and 1200 °C, respectively) of impregnated glucose. Several model Co/Al2O3@C-X catalysts with the same Co3O4 particle size but different cobalt-support interfacial structures were prepared. The effect of the cobalt-supported interface on the properties and Fischer-Tropsch synthesis (FTS) performance of the catalysts was investigated. It was found that the crystal type of Al2O3 and surface oxygen-containing functional group of Al2O3@C-X were affected by carbonization temperature, thus adjusting the structural properties of the catalyst. The surface carbon layer could reduce the interaction between cobalt and Al2O3 and promote the reduction of cobalt species. The stability of the catalyst depends on the nature of oxygen-containing functional groups of Al2O3@C-X. Co/Al2O3@C-1000 exhibited the best FTS performance with 34.1 % CO conversion and 62.8 % C5+ selectivity under the reaction conditions of 230 °C, 1 MPa and 6 SL·gcat.-1·h−1.