Formation of filamentous carbons over supported Fe catalysts through methane decomposition

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

“…As reported by Jin et al [28], there may be an induced period required before Fe particles develop to their full capacities, Journal of Nanomaterials and this result was also found in Ni-doped carbon catalysts [29]. From Figure 7, the methane conversion curves for different Fe content catalysts (10Fe/MRM, 20Fe/MRM, 30Fe/ MRM, and 40Fe/MRM) show similar three-step (increasedecrease-increase) variations with the reaction time, and the variation tendency of methane conversion curves was different in contrast with conventional iron-based catalysts [14,49]. The first step was ascribed to the induction period that was mentioned above.…”

“…Iron species were observed as layers parcelled by carbons, varying in size (from 10 to 60 nm) and morphology with a spherical appearance. TEM images of spherical-like carbons have shown that graphite layers of carbons grow with concentric spheres from the central iron species [14], which can be observed in Figure 9(b). The chain-like carbons are seen in Figures 9(c) and 9(d).…”

“…Figure 9 shows TEM images of carbon deposited on fresh catalysts (10Fe/MRM, 20Fe/MRM, and 30Fe/MRM). These carbons were classified into three types based on their shapes and structures: spherical-like carbons, filamentous carbons with a chain-like structure [14], and carbon nanotubes [17,19] with a long-filament-like structure. The outer diameters of the spherical-like carbons in the TEM images ranged from 40 to 100 nm.…”

“…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.…”

Relationship between carbon morphology and catalyst deactivation in the catalytic decomposition of biogas using Ni, Co and Fe based catalysts

“…The position of these two peaks did not correspond with the γ-Fe peaks position (45.8 and 53.4º). However it has been reported [59] that carbon atoms can dissolve on γ-Fe structure, expanding the lattice and shifting the diffraction lines to lower angles. Both, high reaction temperatures (900 ºC) and carbon production can lead to the formation of this γ-Fe phase with carbon atoms dissolved in the Fe FCC structure.…”