O<SUB>2</SUB>およびCO<SUB>2</SUB>の存在下における鉄系触媒上でのメタン分解

Abstract

Methane decomposition was carried out using Fe/Al2O3 catalyst in the absence and presence of O2 and CO2. Even in the presence of O2 and CO2 (CH4/O2/CO2 = 80/10/5 vol ratio), the deactivation of Fe/Al2O3 catalyst at temperatures below 1100 K was caused mainly by accumulation of carbon products as well as oxidation of nonoxide iron species (α-Fe and Fe3C), as confirmed by X-ray diffraction, TG/DTA, and in-situ DRIFT-IR analyses. The stability of Fe/Al2O3 catalyst in the presence of O2 and CO2 was improved by the addition of some metals into the catalyst (M/Fe = 1/1 wt ratio). Methane conversion decreased monotonously from 95 to 79% after 6 h for Fe/Al2O3 catalyst. In contrast, the activity of Fe/Mg/Al2O3 catalyst at 973 K remained unchanged after 6 h (CH4 conversion 95%). This effect could be associated with the formation of MgFe2O4. The effectiveness of other metal additives on the catalyst stability was Ce, Y > Eu, La> Pr, none > V > Nb.

Hydrogen Production from Steam Reforming of Hydrocarbons over Alkaline-Earth Metal-Modified Fe- or Ni-Based Catalysts

“…These absorptions remained intact after reaction, although structural transformation of ZrO 2 between monoclinic and tetragonal could occur after reaction, as shown in Figure (used catalysts). The formations of these mixed oxides could be consistent with the formation of MgFe 2 O 4 in the CH 4 decomposition/reforming with CO 2 /O 2 …”

“…Preliminary Experiments on Steam Reforming of I so octane at 823 K. To investigate a performance of Fe-based catalyst, the steam reforming of isooctane was carried out at 823 K. The Fe/Mg/Al 2 O 3 catalyst, which was active for CO 2 reforming of methane, produced hydrogen, CH 4 , and CO as detectable gaseous products, while C2 hydrocarbons were not formed, as shown in Figure . The addition of Rh to Fe/Al 2 O 3 catalyst resulted in an increase in CH 4 and C2 formations.…”

“…And a mixture of hexane, isooctane, MCH, and benzene was used as model gasoline. We have already reported that Fe/Mg/Al 2 O 3 catalyst was active for methane decomposition in the presence of O 2 /CO 2 to form hydrogen and carbon …”

Catalytic decomposition of biogas to produce H2-rich fuel gas and carbon nanofibers. Parametric study and characterization

“…To avoid carbon formation, noble metals ( Pd, Rh, Ir, Pt or Ru) have been studied since the carbon formation is greatly inhibited [9]. However, their high cost make them unsuitable for large scale applications and therefore, researchers attention is mainly focused on catalyst based on transition metals such as Ni, Co and Fe [10][11][12]. In the case of nickel based catalysts, the minimization of carbon deposits is achieved either by using different supports such as Al 2 O 3 , CaO, La 2 O 3 or SiO 2 [13][14][15], or doping with other elements, such as Mn, K, Sn, Ca [13] or rare earth mixtures [16].…”

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

“…It is well known that noble metal catalysts meet those requirements [3,4]. However, the high cost of these materials prompted the research on less expensive catalysts like Ni [5][6][7][8][9][10], Co [11][12][13][14] or Fe [15], even though they are prone to carbon generation via CH 4 decomposition (CH 4 ↔ 2H 2 + C, ∆Hº= 75 kJ·mol -1 ) or Boudouard reaction (2CO ↔ C + CO 2 , ∆Hº= -171 kJ·mol -1 ) [16].…”