Effects of surface modification with zirconium phosphate on Ru/Co/SiO2 Fischer–Tropsch catalysts analyzed by XPS and TEM analyses

The effects of surface modification with zirconium phosphate on cobalt-based Fischer–Tropch synthesis (FTS) catalyst to the enhanced catalytic stabilities were explained with the help of the surface sensitive X-ray photoelectron spectroscopy (XPS) and transmission electron spectroscopy (TEM) on the reacted catalysts at three different periods of reaction duration such as 10, 30 and 70 h on stream. The catalyst deactivation was significantly attributed to the aggregation of cobalt clusters at the very beginning of reaction, and the modification of SiO2 surface with the proper amount of zirconium phosphate largely suppressed cobalt aggregation during the reaction period of 70 h. The enhanced catalytic stability is attributed to the homogeneous distribution of cobalt clusters with a low mobility by being confined in the thermally stable zirconium phosphate matrices on SiO2 surface. The roles of zirconium phosphate on catalytic stability are mainly explained by analyzing the relative dispersion of zirconium phosphate as well as cobalt clusters on SiO2 surface with time on stream.

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► The zirconium phosphate modification on Ru/Co/SiO2 FTS catalysts were investigated by XPS and TEM.
► The catalyst deactivation is attributed to the aggregation of cobalt clusters.
► The zirconium phosphate-modified SiO2 enhances catalytic stability by spatial confinement of cobalt clusters.