Reaction-induced Ni-based interstitial carbon atoms for coke-free dry reforming of methane

Abstract

Dry reforming of methane on Ni-based catalyst offers an environmentally and economically viable and pivotal route to produce synthesis gas. The accumulation and polymerization of carbon atoms on the surface of Ni eventually deactivate the catalyst because of coke deposition. Here, we establish a reaction-induced method to isolate carbon atoms into the interstitial position of nickel octahedral sites (O-sites) under reaction condition, which can avoid the C−C bond formation. Al2O3 encapsulated Ni3Zn provides expanded space volume of O-sites in nickel to accommodate carbon atoms, and the further transformation to Ni3ZnC0.7 with superstructure feature was achieved under CH4/CO2 reaction. Ni3ZnC0.7/Al2O3 exhibits excellent activity and stability below 600°C with variable CH4/CO2 ratio (1/4−2/1). These active carbon atoms can be replenished and cycled in Ni3ZnC0.7 interior structure rather than depositing as coke on the surface during the reaction as revealed by in situ experiments.