Synthesis and Characterization of Electrospun Nanofibers of Sr-La-Ce Oxides as Catalysts for the Oxidative Coupling of Methane

Abstract

Catalytic nanofibers composed of LaCe and Sr-LaCe oxides were synthetized by electrospinning method with 5 wt.% of Sr and different La/Ce molar ratios. The materials were obtained by calcining electrospun polymer composite fibers and were studied for the oxidative coupling of methane (OCM). The catalytic performance was compared with analogous Sr-LaCe powder catalysts. SEM micrographs of Sr-LaCe fibers (La/Ce: 0.1, 0.2, 1 and 3) showed nanostructures with homogenous and uniform diameters (170-200 nm). In addition, the XRD patterns revealed the formation of crystalline solid solutions like LaxCeyOz. The strontium enhanced the CH4 conversion and C2 selectivity, since it possibly generated structural defects that promote the formation of superoxide species. The SrLaCe3 nanofibers reached a CH4 conversion of 28.5 % and C2 yield of 21.7 % at 600 ºC. The nanofibers randomly packed improved the heat and mass transfer properties due to a high geometric surface ratio with high bed porosity.

Facile Cr3+-Doping Strategy Dramatically Promoting Ru/CeO2 for Low-Temperature CO2 Methanation: Unraveling the Roles of Surface Oxygen Vacancies and Hydroxyl Groups

“…The peak at low binding energy of ∼528−531 eV can be assigned to lattice oxygen (O latt ). The peak at a high binding energy of ∼531.6 eV can be attributed to a mixture of surface-adsorbed oxygen species (O ads ), including surface OH and carbonate (CO 3 2− ) groups, 42 of which the latter can be further verified by the signal at around 288.5 eV in the C 1s spectra 38 (Figure 5c). The surface O ads /(O ads + O latt ) molar ratios were also calculated in Table 4 through dividing the integrated area of the O ads peak by the sum integrated area of the O ads and O latt peaks.…”

Metal Ions (Li, Mg, Zn, Ce) Doped into La2O3 Nanorod for Boosting Catalytic Oxidative Coupling of Methane

“…A series of high-efficient catalysts for the OCM reaction have been designed and fabricated, such as Na-W-Mn oxides [6,7], Li-MgO [8], ABO 3 perovskite-type oxides [9], rare earth oxides [10] and so on [11][12][13]. Among the catalysts, Na-W-Mn-based catalysts have high catalytic performance during the OCM reaction process, and its yield of ethane and ethylene (C2) products can reach nearly 25% [14].…”

Oxidative coupling of methane—comparisons of MnTiO3–Na2WO4 and MnOx–TiO2–Na2WO4 catalysts on different silica supports

“…The peaks around 530.5–530.9 eV for M–O in NW/CS and NW/SG were relatively small (as NW/CS and NW/SG had no components of Mn–O and Ti–O), while relatively large peaks were observed for MnTiO 3 -NW/CS, MnTiO 3 -NW/SG, and Mn-Ti-NW/SG. The O - , and O 2 - lattice species are essential for CH 4 activation 66 , 67 , whereas the O 2- lattice species leads to complete oxidation of hydrocarbon products to CO x 60 . Based on the activity results in Fig.…”