Formation and reactivity of surface carbonaceous species from ethylene decomposition on Ni-based catalyst treated using dielectric barrier discharge plasma

Abstract

Ni-based catalysts prepared using dielectric barrier discharge (DBD) plasma exhibit significantly enhanced coke resistance, leading to higher stability in catalytic reactions. The structural effect of the catalysts on the produced carbonaceous species required a thorough analysis. Herein, the low-temperature carbon deposition performance of a DBD plasma-treated Ni-based catalyst (named Ni/SiO2-P) was studied through ethylene decomposition. It aimed to detect the surface carbonaceous species and investigate their evolvement mechanism. Extensive characterization demonstrated that more Ni active sites on Ni/SiO2-P improved ethylene decomposition with a higher yield of atomic carbon and highly reactive carbonaceous species, such as dissolved carbon and organic compounds. These species aggregated into onion-like carbon, CNFs, and CNTs, acting as deactivating carbonaceous species. Compared to a thermally calcined Ni catalyst, Ni/SiO2-P exhibited the lower formation of the deactivating carbonaceous species with smaller sizes and lower degrees of graphitization. The long-term tests for CO2 reforming of methane supported that the carbonaceous species on Ni/SiO2-P were more easily gasified with the absence of obvious deactivating carbonaceous species. The more stable Ni structure induced by the stronger Ni-support interaction provided an advantage in terms of hindering the growth of the deactivating carbonaceous species. This work thoroughly examined the enhanced coke resistance and catalytic stability of Ni/SiO2-P. It provides valuable insights into the development of DBD plasma-assisted catalyst synthesis for sustainable and efficient chemical reactions.