Evolution and performances of Ni single atoms trapped by mesoporous ceria in Dry Reforming of Methane

Bulk ceria can stabilize metal single atoms in oxidizing conditions. However, the obtained catalysts undergo sintering at high temperatures, due to the poor stability of the support. In this work, we prepared ordered mesoporous ceria (mp-CeO2) to trap Ni single atoms in dry reforming of CH4 (DRM). We found that the Ni1@mp-CeO2 catalyst presented many oxygen vacancies (OV) and basic sites, helping to activate CO2 and generate reactive oxygen to remove carbon deposits, as compared to a Ni1/CeO2 sample prepared by impregnation. Moreover, the confinement of mesoporous CeO2 prevents the sintering of Ni clusters derived from Ni single atoms and enhances the stability of the catalyst. The Ni1@mp-CeO2 catalyst has a higher CH4 conversion, and less deactivation rate, as compared to the Ni1/CeO2. This work demonstrates Ni single atoms undergo growth to nanoclusters in DRM and the use of Ni single atoms as catalyst precursor can suppress the carbon deposition.