Efficient CeO2 decoration of Fischer-Tropsch catalysts through atomic layer deposition

Abstract

The development of efficient catalysts for the Fischer–Tropsch synthesis (FTS) was investigated using atomic layer deposition (ALD) for the controlled promotion of Co/γ-Al₂O₃ catalysts with CeO₂. The deposition of ultra-low Ce loadings (<0.05 wt%) via ALD led to the formation of new active surface sites, as evidenced by DRIFTS-CO studies, and significantly modified the catalytic performance under FTS conditions (10 bar, 230 °C). Catalysts decorated with CeO₂ via ALD exhibited enhanced activity and altered hydrocarbon selectivity compared to unpromoted Co/γ-Al₂O₃. The sequence of CeO₂ incorporation using ALD proved to be decisive for catalysts performance. When CeO₂ was deposited on previously impregnated Co/γ-Al₂O₃, the catalysts showed improved selectivity toward C₅₊ hydrocarbons. In contrast, materials where cobalt was impregnated onto CeO₂-predecorated supports exhibited higher activity but experienced deactivation and a shift in product distribution toward light gases (C₁-C₄) and gasoline-range hydrocarbons. These results highlight the potential of ALD as a precise and effective approach to optimize promoter effects of oxides in Co-based FTS catalysts.