Kinetic and mechanistic features of carbon dioxide reforming of methane over Co–Ce/ZrO 2 catalysts

Carbon dioxide reforming of methane (CDRM) is an effective route to utilize CO 2 and CH 4 , the most abundant, thermodynamically stable and hazardous greenhouse gases. To overcome the economical impediments to favor CDRM's industrial applicability, its mechanistic features need to be revealed both for developing efficient catalysts and optimizing operational conditions. In this context, this work aims to obtain power‐law type CDRM kinetic expressions over 5%Co–2%Ce/ZrO 2 and 10%Co–2%Ce/ZrO 2 catalysts and compare and analyze mechanistic routes to elucidate the effect of the Co:Ce ratio on kinetics. The empirical power‐law type rate expressions were estimated with the reaction orders of 1.63 and 1.12 for CH 4 and 0.29 and –0.12 for CO 2 for 5%Co–2%Ce/ZrO 2 and 10%Co–2%Ce/ZrO 2 catalysts, respectively. Limited CH 4 activation and, thus, carbon formation due to low Co loading lead to accumulation of surface oxygen on ZrO 2 as redox ability of Ce becomes suppressed. This causes higher CO 2 activation barrier. The presence of H 2 in the feed slows down mechanistic steps involving CH x . The reactions including CH 4 activation, most probably reversible direct CH 4 dissociation, are found to be rate determining.