A Comprehensive Mechanistic\nStudy for Dry Reforming\nof Methane over CeO<sub>2</sub>‑Supported TM<sub>4</sub> clusters\n(TM = Ru, Pt, Co, Ni)

In this work, the mechanism of dry reforming of methane\n(DRM) over\na series of CeO<sub>2</sub> (111)-supported transition metal (TM)\nclusters, TM<sub>4</sub>/CeO<sub>2</sub>(111) (TM = Ru, Pt, Co, Ni),\nwas investigated by using density functional theory (DFT) and microkinetic\nmodeling. According to the results of DFT calculations, Ru<sub>4</sub>/CeO<sub>2</sub>(111) and Co<sub>4</sub>/CeO<sub>2</sub>(111) exhibit\nstrong oxygen adsorption capabilities due to the oxophilic properties\nof Ru and Co metals, which facilitate CO<sub>2</sub> activation more\neffectively than other metals. Ru<sub>4</sub>/CeO<sub>2</sub>(111)\ndemonstrates the highest efficiency for both CH<sub>4</sub> and CO<sub>2</sub> activation. Pt<sub>4</sub>/CeO<sub>2</sub>(111) has great\nanticoking ability because the C* coupling has a higher energy barrier.\nMicrokinetic simulations indicate that the turnover frequency (TOF)\nrate follows the trend: Ru<sub>4</sub>/CeO<sub>2</sub>(111) > Pt<sub>4</sub>/ CeO<sub>2</sub>(111) > Co<sub>4</sub>/CeO<sub>2</sub> (111)\n> Ni<sub>4</sub>/ CeO<sub>2</sub>(111). Ru/CeO<sub>2</sub> exhibits\nthe highest activity and selectivity. Pt/CeO<sub>2</sub> has the best\nability for anticoking due to the high energy barrier of C* coupling.\nCo/CeO<sub>2</sub> is prone to deactivation from oxygen poisoning,\nattributed to its strong oxophilic properties and weak CH<sub>4</sub> activation ability, Ni/CeO<sub>2</sub> shows the poorest activity\nand stability, as it is easily deactivated by coke formation and has\nthe lowest selectivity. The analysis of key steps indicates that there\nare different rate-controlled steps for various metals due to inherent\ndifferences in their properties. We anticipate that our results will\noffer a strategy for designing DRM catalysts by selecting the appropriate\nmetal catalysts.