Deactivation of CeO2-Promoted Co/SiO2 Fischer-Tropsch Catalysts

The catalytic performance of the CeO2-Co/SiO2 catalyst was investigated for Fischer-Tropsch synthesis on a lab-scale fixed-bed reactor filled with 1.5 L catalyst (1–3 mm) for 300 h under the reaction conditions of 1.5 MPa, 488 K, and 400 h−1. The catalyst was characterized by temperature-programmed reduction, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy. The catalyst exhibited a CO conversion of 41%, a C5+ selectivity of 85%, and a CH4 selectivity of 10%. XRD results revealed the presence of CoO and cobalt silicate species on the catalyst that was located near the outlet of the reactor after reaction. It was proposed that the cobalt silicate species was formed through reaction 2Co + SiO2 + 2H2O→Co2SiO4 + 2H2 via a CoO intermediate, which was kinetically restricted under typical Fischer-Tropsch synthesis conditions.