Characterization of active sites for methane decomposition on carbon black through acetylene chemisorption

Hydrogen Production by Thermocatalytic Methane Decomposition

“…ACs and CBs showed reasonable activity and stability at around 1123 K. It was found that the disordered forms of carbon (e.g., AC, CB) were in general more catalytically active than ordered ones (graphite and diamond powder). After Muradov's pioneering work in 2001, many other reports were published in which ACs [11,[13][14][15][16], CBs [17][18][19], or both [20,21] were widely studied. However, carbon materials did not perform well since the methane conversions reported were quite low and there was a strong deactivation due to carbon deposition.…”

Preparation of Modified Red Mud-Supported Fe Catalysts for Hydrogen Production by Catalytic Methane Decomposition

“…The first step was ascribed to the induction period that was mentioned above. In the second step, methane conversion showed a slow decrease with the reaction time, which may be due to inactive carbon deposits [22,24] produced during CMD which covered the Fe active sites, although the catalysts were not completely deactivated. In the third step, methane conversion showed a quick increase with the reaction time and stably continued to increase, which indicated that some other factors besides Fe played a role in improving methane conversion during this time.…”

“…Many works have been reported on CMD using metal catalysts, such as Fe [12][13][14][15], Co [16,17], Ni [18][19][20][21], carbon materials [22][23][24][25][26][27], 2 Journal of Nanomaterials three red mud samples for hydrogen production by CMD. The highest methane conversion obtained in their study was 19.8% with a corresponding methane conversion rate of 18.0 × 10 −6 mol CH 4 /g cat /s, which is associated with a sample containing the highest proportion of iron, and two other samples exhibited poorer activity than this sample did.…”

Variation in Catalytic Activity of Carbon Black during Methane Decomposition: Active Site Estimations from Surface Structural Characteristics

“…The use of carbonaceous materials as catalysts in methane decomposition has also been investigated [1,2,[5][6][7][8][9][10][11][12]. Carbon catalysts offer several advantages over metal catalysts, such as resistance to high temperatures, tolerance to sulfur and other potentially harmful impurities in the feedstock [2], and lower cost [8].…”

“…On the basis of this observation, it is reasonable to consider that the variation in the number of active sites is responsible for the activity variation. Although no method has been established to determine the number of active sites of CB directly [6], the surface structural characteristics are expected to correlate with the variation in the number of active sites because the active sites consist of edge sites and defects in nanosized graphitic sheets. In the present study, therefore, we present an approach to consider the variation in the number of active sites during the reaction from a surface structural viewpoint.…”