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

Abstract

Catalytic nanofibers composed of La-Ce and Sr-La-Ce oxides were synthesized by the electrospinning method with 5 wt % 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. The catalytic performance was compared with analogous Sr-La-Ce powder catalysts. SEM micrographs of Sr-La-Ce fibers (La/Ce: 0.1, 0.2, 1, and 3) showed nanostructures with homogeneous 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 °C. The randomly packed nanofibers improved the heat and mass transfer properties due to their high geometric surface ratio with high bed porosity.