Oxychlorination of methane over FeO_x/CeO_2 catalysts

摘要

Methane activation through oxychlorination is in the spotlight due to the relatively mild reaction conditions at atmospheric pressure and in the temperature range of 450-550 degrees C. Although CeO2 is known to exhibit good activity for methane oxychlorination, significant amounts of by-products such as CO2, CO and carbon deposits are produced during the reaction over CO2. We investigated the effect of iron in FeOx/CeO2 catalysts on methane oxychlorination. FeOx/CeO2 with 3 wt% iron shows the maximum yield at 510 degrees C with 23% conversion of methane and 65% selectivity of chloromethane. XRD and H-2 TPR results indicate that iron-cerium solid solution was formed, resulting in the production of more easily reduced cerium oxide and the suppression of catalysts sintering during the reaction. Furthermore, the selectivity of by-products decreased more significantly over FeOx/CeO2 than cerium oxide, which can be attributed to the facilitation of HCl oxidation arising from the enhanced reducibility of the former sample.