Effect of hydrogen additive on methane decomposition to hydrogen and carbon over activated carbon catalyst.

The effect of H 2 addition on CH 4 decomposition over activated carbon (AC) catalyst was investigated. The results show that the addition of H 2 to CH 4 changes both methane conversion over AC and the properties of carbon deposits produced from methane decomposition. The initial methane conversion declines from 6.6% to 3.3% with the increasing H 2 flowrate from 0 to 25 mL/min, while the methane conversion in steady stage increases first and then decreases with the flowrate of H 2 , and when the H 2 flowrate is 10 mL/min, i.e. quarter flowrate of methane, the methane conversion over AC in steady stage is four times more than that without hydrogen addition. It seems that the activity and stability of catalyst are improved by the introduction of H 2 to CH 4 and the catalyst deactivation is restrained. Filamentous carbon is obtained when H 2 is introduced into CH 4 reaction gas compared with the agglomerate carbon without H 2 addition. The formation of filamentous carbon on the surface of AC and slower decrease rate of surface area and pores volume may cause the stable activity of AC during methane decomposition. [ABSTRACT FROM AUTHOR]