Oxidative Coupling of Methane over SrO/La2O3 Catalyst in an Oxygen-Permeable Separation Membrane Reactor

A facile mixed complex synthesis method for perovskite oxides toward electrocatalytic oxygen reduction

The perovskite-type La(0.5+x)Sr(0.5-x)FeO3-δ (x = 0.00, 0.10, 0.20) oxides for the electrocatalytic oxygen reduction reaction (ORR) were synthesized by a facile reaction-EDTA/citric acid mixed complex sol-gel method. The cubic single-phase perovskite structure of the as-prepared oxides is demonstrated using powder X-ray diffraction (XRD). Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy/selected area electron diffraction (TEM-SAED), and X-ray photoelectron spectroscopy (XPS) characterizations were also conducted for the perovskite-type La(0.5+x)Sr(0.5-x)FeO3-δ (x = 0.00, 0.10, 0.20) oxides. Furthermore, the electrochemical ORR properties of the as-prepared oxides in alkaline media were studied, with the oxides exhibiting good electrocatalytic ORR performance.

Development of Membrane Reactor Coupling Hydrogen and Syngas Production

Simultaneous syngas and pure hydrogen production through partial oxidation of methane and water splitting, respectively, were demonstrated by using mixed ionic-electronic conductors. Tubular ceramic membranes prepared from La_0.5Sr_0.5FeO₃ perovskite were successfully utilized in a 10 M lab scale reactor by applying a radial arrangement. The supply of methane to the middle area of the reaction zone was shown to provide a uniform distribution of the chemical load along the tubes' length. A steady flow of steam feeding the inner part of the membranes was used as oxidative media. A described configuration was found to be favorable to maintaining oxygen permeability values exceeding 1.1 mL∙cm^-2∙min^-1 and long-term stability of related functional characteristics. Methane's partial oxidation reaction assisted by 10%Ni@Al₂O₃ catalyst proceeded with selectivity values above 90% and conversion of almost 100%. The transition from a laboratory model of a reactor operating on one tubular membrane to a ten-tube one resulted in no losses in the specific performance. The optimized supply of gaseous fuel opens up the possibility of scaling up the reaction zone and creating a promising prototype of a multitubular reaction zone with a simplified sealing procedure.