Anchoring metal cobalt species on defective alumina for enhanced catalytic performance in F-T synthesis

For supported heterogeneous catalyst, metal-support interaction (MSI) is very important factors for catalytic performance. Commercial γ-alumina was reduced with hydrogen in advance, providing strong anchoring sites for metal (metal oxide) species. This research demonstrates the use of pre-reduced alumina as catalyst carrier to anchor metal Co species in FTS compared with unreduced one. The defective alumina supported catalyst displayed a supeior performance. The Co/RAl2O3-550 catalyst showed surprisingly high CO conversion of 56.0%, C5+ hydrocarbons selectivity of 93.2%, and a low methane selectivity of 2.7% at a remarkable high activity (CTY = 1.1 × 10-5 molCO gCo-1 s−1). It revealed the strong reduction of alumina generated more defective sites, which was strongly anchored with metal cobalt species under MSI. Besides, the reduction of alumina also boosted the number of surface L-acidity, promoting the CO absorption rate through CO dissociation. These results reveal the unique property of defective Al2O3 supported cobalt catalysts, and provide a practical strategy to explore stable and efficient FTS catalysts.