Coke deactivation of activated carbon-supported rubidium–potassium catalyst for C2F5I gas-phase synthesis

The coke formed on the Rb–K/AC catalysts during the synthesis of C2F5I by the reaction between C2HF5 and I2 was investigated using N2 adsorption–desorption, thermogravimetry and differential thermal analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). The results indicated that the deactivation was mainly caused by the deposition of coke which induced micropore blockage and active sites coverage. The coke species on the Rb–K/AC catalysts surface included carbonaceous carbon and fluorocarbons with low F/C radio, and had different structures to that of graphite. Moreover, the deactivated catalyst was easily reactivated by burning out the coke formed on the catalyst by the addition of O2 at 150–350 °C, and the reactivated catalyst exhibited catalytic activity almost as high as the fresh sample.