Catalytic decomposition of methane over activated carbon
ABSTRACT Methane decomposition over activated carbons was carried out in a fixed bed, quartz-tube flow reactor. The kinetics of methane decomposition and surface properties changes before and after reaction was investigated. As a non-carbon based material, active alumina was also used to compare and understand the catalytic decomposition mechanism of methane over different materials. A reaction order of 0.5 is obtained for methane decomposition over ACs and activation energies in the range from 117 to 185 kJ mol−1. The pore size change in the course of methane decomposition over activated carbons indicates that the catalytic reaction occurs mainly in the micropores. Activated alumina has different pore properties and carbon deposition in mesopores of the alumina is responsible for the catalytic activity.
Article: Methane decomposition over Ni loaded activated carbon for hydrogen production and the formation of filamentous carbon[show abstract] [hide abstract]
ABSTRACT: Methane decomposition over Ni loaded activated carbon (AC) was investigated in a fixed-bed reactor, and the results were compared with those of the individual methane decomposition over AC. XRD results show that there is no NiO observed, and only Ni metal crystallite is found in the catalyst even if it is calcined in Ar, which eliminates the inevitable reduction step with other supports. When Ni is loaded on AC, the Ni/AC catalyst shows higher activity in methane decomposition than the original carbon. Ni crystal size increasing and the new crystallite Ni3C formation during the process lead to the deactivation of the catalysts. Filamentous carbon formation is observed and interlaced with the deactivated catalyst surface at moderate condition with low amount of Ni loaded. Temperature has great effect on the catalytic performance of Ni/AC catalyst and the formation as well as the characterization of the filamentous carbons.International Journal of Hydrogen Energy.