The interparticle oxygen vacancies enrichment in the matrix of fibrous silica ceria supported nickel for CO methanation

Abstract

Aspherical nickel-loaded fibrous silica mesoporous ceria (Ni/FSCe) with a cockscomb-like structure has been synthesized using a microemulsion technique integrated with a crystal-seed crystallization process and unprecedently utilized for CO methanation. Numerous systems were used to characterize the catalysts systematically. The Ni/FSCe showed greatly enhanced catalytic capability with the CO conversion of 95.67 % and the CH4 yield of 91.20 % at 400 °C, which is higher than that of the nickel-ceria loaded onto conventional KCC-1 (Ni-Ce/KCC-1). Furthermore, it demonstrated excellent stability, with no indication of deactivation for 75 h. Numerous factors, including the synergistic effect of high amount of inter-nanoparticle oxygen vacancies which lead towards high basicity and well-dispersed Ni, which act as both carbon monoxide and hydrogen adsorption sites, are considered to be responsible for the significant improvement in CO methanation. The superiority in the activity and stability of Ni/FSCe over Ni-Ce/KCC-1 also could be attributed towards better metal-support interactivity between the Ni nanoparticles and CeO2 support, which helps to inhibit crystallite migration and provides protection against carbon deposition. Core-shell FSCe, with their high catalytic characteristics, imply significant application potential in basic-catalyzed reactions, particularly methane generation.