In situ X-ray diffraction computed tomography studies examining the thermal and chemical stabilities of working Ba0.5Sr0.5Co0.8Fe0.2O3−δ membranes during oxidative coupling of methane
| Autor: | Andrew M. Beale, Antonis Vamvakeros, Gavin Vaughan, Vesna Middelkoop, Robert J. Cernik, Simon D. M. Jacques, Miren Agote Arán, Dorota Matras |
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| Rok vydání: | 2020 |
| Předmět: |
In situ
Diffraction Materials science General Physics and Astronomy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Catalysis Membrane Chemical engineering Yield (chemistry) Phase (matter) X-ray crystallography Oxidative coupling of methane Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | 'Physical Chemistry Chemical Physics ', vol: 22, pages: 18964-18975 (2020) |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | In this study we present the results from twoin situX-ray diffraction computed tomography experiments of catalytic membrane reactors (CMRs) using Ba0.5Sr0.5Co0.8Fe0.2O3-delta(BSCF) hollow fibre membranes and Na-Mn-W/SiO(2)catalyst during the oxidative coupling of methane (OCM) reaction. The negative impact of CO2, when added to the inlet gas stream, is seen to be mainly related to the C(2+)yield, while no evidence of carbonate phase(s) formation is found during the OCM experiments. The main degradation mechanism of the CMR is suggested to be primarily associated with the solid-state evolution of the BSCF phase rather than the presence of CO2. Specifically,in situXRD-CT and post-mortem SEM/EDX measurements revealed a collapse of the cubic BSCF phase and subsequent formation of secondary phases, which include needle-like structures and hexagonal Ba(6)Co(4)O(12)and formation of a BaWO(4)layer, the latter being a result of chemical interaction between the membrane and catalyst materials at high temperatures. |
| Databáze: | OpenAIRE |
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